Patent Publication Number: US-2022218344-A1

Title: Surgical instrument comprising a sensor system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 15/798,855, entitled SURGICAL INSTRUMENT COMPRISING A SENSOR SYSTEM, filed Oct. 31, 2017, now U.S. Patent Application Publication No. 2018/0132850, which is a continuation-in-part application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 14/226,142, entitled SURGICAL INSTRUMENT COMPRISING A SENSOR SYSTEM, filed Mar. 26, 2014, which issued on Mar. 13, 2018 as U.S. Pat. No. 9,913,642, the entire disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     The present invention relates to surgical instruments and, in various circumstances, to surgical stapling and cutting instruments and staple cartridges therefor that are designed to staple and cut tissue. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a surgical instrument that has an interchangeable shaft assembly operably coupled thereto; 
         FIG. 2  is an exploded assembly view of the interchangeable shaft assembly and surgical instrument of  FIG. 1 ; 
         FIG. 3  is another exploded assembly view showing portions of the interchangeable shaft assembly and surgical instrument of  FIGS. 1 and 2 ; 
         FIG. 4  is an exploded assembly view of a portion of the surgical instrument of  FIGS. 1-3 ; 
         FIG. 5  is a cross-sectional side view of a portion of the surgical instrument of  FIG. 4  with the firing trigger in a fully actuated position; 
         FIG. 6  is another cross-sectional view of a portion of the surgical instrument of  FIG. 5  with the firing trigger in an unactuated position; 
         FIG. 7  is an exploded assembly view of one form of an interchangeable shaft assembly; 
         FIG. 8  is another exploded assembly view of portions of the interchangeable shaft assembly of  FIG. 7 ; 
         FIG. 9  is another exploded assembly view of portions of the interchangeable shaft assembly of  FIGS. 7 and 8 ; 
         FIG. 10  is a cross-sectional view of a portion of the interchangeable shaft assembly of  FIGS. 7-9 ; 
         FIG. 11  is a perspective view of a portion of the shaft assembly of  FIGS. 7-10  with the switch drum omitted for clarity; 
         FIG. 12  is another perspective view of the portion of the interchangeable shaft assembly of  FIG. 11  with the switch drum mounted thereon; 
         FIG. 13  is a perspective view of a portion of the interchangeable shaft assembly of  FIG. 11  operably coupled to a portion of the surgical instrument of  FIG. 1  illustrated with the closure trigger thereof in an unactuated position; 
         FIG. 14  is a right side elevational view of the interchangeable shaft assembly and surgical instrument of  FIG. 13 ; 
         FIG. 15  is a left side elevational view of the interchangeable shaft assembly and surgical instrument of  FIGS. 13 and 14 ; 
         FIG. 16  is a perspective view of a portion of the interchangeable shaft assembly of  FIG. 11  operably coupled to a portion of the surgical instrument of  FIG. 1  illustrated with the closure trigger thereof in an actuated position and a firing trigger thereof in an unactuated position; 
         FIG. 17  is a right side elevational view of the interchangeable shaft assembly and surgical instrument of  FIG. 16 ; 
         FIG. 18  is a left side elevational view of the interchangeable shaft assembly and surgical instrument of  FIGS. 16 and 17 ; 
         FIG. 18A  is a right side elevational view of the interchangeable shaft assembly of  FIG. 11  operably coupled to a portion of the surgical instrument of  FIG. 1  illustrated with the closure trigger thereof in an actuated position and the firing trigger thereof in an actuated position; 
         FIG. 19  is a perspective view of a portion of an interchangeable shaft assembly showing an electrical coupler arrangement; 
         FIG. 20  is an exploded assembly view of portions of the interchangeable shaft assembly and electrical coupler of  FIG. 19 ; 
         FIG. 21  is a perspective view of circuit trace assembly; 
         FIG. 22  is a plan view of a portion of the circuit trace assembly of  FIG. 21 ; 
         FIG. 23  is a perspective view of a portion of another interchangeable shaft assembly showing another electrical coupler arrangement; 
         FIG. 24  is an exploded assembly view of portions of the interchangeable shaft assembly and electrical coupler of  FIG. 23 ; 
         FIG. 25  is an exploded slip ring assembly of the electrical coupler of  FIGS. 23 and 24 ; 
         FIG. 26  is a perspective view of a portion of another interchangeable shaft assembly showing another electrical coupler arrangement; 
         FIG. 27  is an exploded assembly view of portions of the interchangeable shaft assembly and electrical coupler of  FIG. 26 ; 
         FIG. 28  is a front perspective view of a portion of the slip ring assembly of the electrical coupler of  FIGS. 26 and 27 ; 
         FIG. 29  is an exploded assembly view of the slip ring assembly portion of  FIG. 28 ; 
         FIG. 30  is a rear perspective view of the portion of slip ring assembly of  FIGS. 28 and 29 ; 
         FIG. 31  is a perspective view of a surgical instrument comprising a power assembly, a handle assembly, and an interchangeable shaft assembly; 
         FIG. 32  is perspective view of the surgical instrument of  FIG. 31  with the interchangeable shaft assembly separated from the handle assembly; 
         FIG. 33 , which is divided into  FIGS. 33A and 33B , is a circuit diagram of the surgical instrument of  FIG. 31 ; 
         FIG. 34  is a block diagram of interchangeable shaft assemblies for use with the surgical instrument of  FIG. 31 ; 
         FIG. 35  is a perspective view of the power assembly of the surgical instrument of  FIG. 31  separated from the handle assembly; 
         FIG. 36  is a block diagram the surgical instrument of  FIG. 31  illustrating interfaces between the handle assembly and the power assembly and between the handle assembly and the interchangeable shaft assembly; 
         FIG. 37  is a power management module of the surgical instrument of  FIG. 31 ; 
         FIG. 38  is a perspective view of a surgical instrument comprising a power assembly and an interchangeable working assembly assembled with the power assembly; 
         FIG. 39  is a block diagram of the surgical instrument of  FIG. 38  illustrating an interface between the interchangeable working assembly and the power assembly; 
         FIG. 40  is a block diagram illustrating a module of the surgical instrument of  FIG. 38 ; 
         FIG. 41  is a perspective view of a surgical instrument comprising a power assembly and a interchangeable working assembly assembled with the power assembly; 
         FIG. 42  is a circuit diagram of an exemplary power assembly of the surgical instrument of  FIG. 41 ; 
         FIG. 43  is a circuit diagram of an exemplary power assembly of the surgical instrument of  FIG. 41 ; 
         FIG. 44  is a circuit diagram of an exemplary interchangeable working assembly of the surgical instrument of  FIG. 41 ; 
         FIG. 45  is a circuit diagram of an exemplary interchangeable working assembly of the surgical instrument of  FIG. 41 ; 
         FIG. 46  is a block diagram depicting an exemplary module of the surgical instrument of  FIG. 41 ; 
         FIG. 47A  is a graphical representation of an exemplary communication signal generated by a working assembly controller of the interchangeable working assembly of the surgical instrument of  FIG. 41  as detected by a voltage monitoring mechanism; 
         FIG. 47B  is a graphical representation of an exemplary communication signal generated by a working assembly controller of the interchangeable working assembly of the surgical instrument of  FIG. 41  as detected by a current monitoring mechanism; 
         FIG. 47C  is a graphical representation of effective motor displacement of a motor of the interchangeable working assembly of  FIG. 41  in response to the communication signal generated by the working assembly controller of  FIG. 47A ; 
         FIG. 48  is a perspective view of a surgical instrument comprising a handle assembly and a shaft assembly including an end effector; 
         FIG. 49  is a perspective view of the handle assembly of the surgical instrument of  FIG. 48 ; 
         FIG. 50  is an exploded view of the handle assembly of the surgical instrument of  FIG. 48 ; 
         FIG. 51  is a schematic diagram of a bailout feedback system of the surgical instrument of  FIG. 48 ; 
         FIG. 52  is a block diagram of a module for use with the bailout feedback system of  FIG. 51 ; 
         FIG. 53  is a block diagram of a module for use with the bailout feedback system of  FIG. 51 ; 
         FIG. 54  illustrates one instance of a power assembly comprising a usage cycle circuit configured to generate a usage cycle count of the battery back; 
         FIG. 55  illustrates one instance of a usage cycle circuit comprising a resistor-capacitor timer; 
         FIG. 56  illustrates one instance of a usage cycle circuit comprising a timer and a rechargeable battery; 
         FIG. 57  illustrates one instance of a combination sterilization and charging system configured to sterilize and charge a power assembly simultaneously; 
         FIG. 58  illustrates one instance of a combination sterilization and charging system configured to sterilize and charge a power assembly having a battery charger formed integrally therein; 
         FIG. 59  is a schematic of a system for powering down an electrical connector of a surgical instrument handle when a shaft assembly is not coupled thereto; 
         FIG. 60  is a flowchart depicting a method for adjusting the velocity of a firing element according to various embodiments of the present disclosure; 
         FIG. 61  is a flowchart depicting a method for adjusting the velocity of a firing element according to various embodiments of the present disclosure; 
         FIG. 62  is a partial, perspective view of an end effector and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 63  is partial, perspective view of an end effector and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 64  is a cross-sectional, elevation view of an end effector and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 65  is a cross-sectional, elevation view of an end effector and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 66  is a partial, perspective view of an end effector with portions removed and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 67  is a partial, perspective view of an end effector with portions removed and a fastener cartridge according to various embodiments of the present disclosure; 
         FIG. 68A  is a schematic depicting an integrated circuit according to various embodiments of the present disclosure; 
         FIG. 68B  is a schematic depicting a magnetoresistive circuit according to various embodiments of the present disclosure; 
         FIG. 68C  is a table listing various specifications of a magnetoresistive sensor according to various embodiments of the present disclosure; 
         FIG. 69  is a perspective view of a surgical instrument comprising a power assembly, a handle assembly, and an interchangeable shaft assembly; 
         FIG. 70  is perspective view of the surgical instrument of  FIG. 69  with the interchangeable shaft assembly separated from the handle assembly; 
         FIG. 71 , which is divided into  FIGS. 71A and 71B , is a circuit diagram of the surgical instrument of  FIG. 69 ; 
         FIG. 72 , which is divided into  FIGS. 72A and 72B , illustrates one embodiment of a segmented circuit comprising a plurality of circuit segments configured to control a powered surgical instrument; 
         FIG. 73 , which is divided into  FIGS. 73A and 73B , illustrates a segmented circuit comprising a safety processor configured to implement a watchdog function; 
         FIG. 74  illustrates a block diagram of one embodiment of a segmented circuit comprising a safety processor configured to monitor and compare a first property and a second property of a surgical instrument; 
         FIG. 75  illustrates a block diagram illustrating a safety process configured to be implemented by a safety processor; 
         FIG. 76  illustrates one embodiment of a four by four switch bank comprising four input/output pins; 
         FIG. 77  illustrates one embodiment of a four by four bank circuit comprising one input/output pin; 
         FIG. 78 , which is divided into  FIGS. 78A and 78B , illustrates one embodiment of a segmented circuit comprising a four by four switch bank coupled to a primary processor; 
         FIG. 79  illustrates one embodiment of a process for sequentially energizing a segmented circuit; 
         FIG. 80  illustrates one embodiment of a power segment comprising a plurality of daisy chained power converters; 
         FIG. 81  illustrates one embodiment of a segmented circuit configured to maximize power available for critical and/or power intense functions; 
         FIG. 82  illustrates one embodiment of a power system comprising a plurality of daisy chained power converters configured to be sequentially energized; 
         FIG. 83  illustrates one embodiment of a segmented circuit comprising an isolated control section; 
         FIG. 84  illustrates one embodiment of a segmented circuit comprising an accelerometer; 
         FIG. 85  illustrates one embodiment of a process for sequential start-up of a segmented circuit; 
         FIG. 86  illustrates one embodiment of a method  1950  for controlling a surgical instrument comprising a segmented circuit, such as, for example, the segmented control circuit  1602  illustrated in  FIG. 80 ; 
         FIG. 87  is a perspective view of a surgical instrument comprising a handle assembly and a shaft assembly including an end effector; 
         FIG. 88  is a perspective view of the handle assembly of the surgical instrument of  FIG. 87 ; 
         FIG. 89  is a schematic block diagram of a control system of the surgical instrument of  FIG. 87 ; 
         FIG. 90  is a schematic block diagram of a module for use with the surgical instrument of  FIG. 87 ; 
         FIG. 91  is a schematic block diagram of a module for use with the surgical instrument of  FIG. 87 ; 
         FIG. 92  is a schematic block diagram of a module for use with the surgical instrument of  FIG. 87 ; 
         FIG. 93  is a schematic illustration of an interface of the surgical instrument of  FIG. 87  in an inactive or neutral configuration; 
         FIG. 94  is a schematic illustration of the interface of  FIG. 93  activated to articulate an end effector; 
         FIG. 95  is a schematic illustration of the interface of  FIG. 93  activated to return the end effector to an articulation home state position; 
         FIG. 96  is a schematic illustration of a partial view of a handle assembly of the surgical instrument of  FIG. 87  depicting a display; 
         FIG. 97  depicts a module of the surgical instrument of  FIG. 87 ; 
         FIG. 98A  is a schematic illustration of a screen orientation of the display of  FIG. 96 ; 
         FIG. 98B  is a schematic illustration of a screen orientation of the display of  FIG. 96 ; 
         FIG. 98C  is a schematic illustration of a screen orientation of the display of  FIG. 96 ; 
         FIG. 98D  is a schematic illustration of a screen orientation of the display of  FIG. 96 ; 
         FIG. 99  depicts a module of the surgical instrument of  FIG. 87 ; 
         FIG. 100A  is a side view of the handle assembly of  FIG. 96  in an upright position; 
         FIG. 100B  is a side view of the handle assembly of  FIG. 96  in an upside down position; 
         FIG. 101  is a schematic illustration of the display of  FIG. 96  showing a plurality of icons; 
         FIG. 102  is a schematic illustration of the display of  FIG. 96  showing a navigational menu; 
         FIG. 103  is a schematic block diagram of an indicator system of the surgical instrument of  FIG. 87 ; 
         FIG. 104  is a module of the surgical instrument of  FIG. 87 ; 
         FIG. 105  is a perspective view of the surgical instrument of  FIG. 87  coupled to a remote operating unit; 
         FIG. 106  is a perspective view of the surgical instrument of  FIG. 87  coupled to a remote operating unit; 
         FIG. 107  is a schematic block diagram of the surgical instrument of  FIG. 87  in wireless communication with a remote operating unit; 
         FIG. 108  is a schematic illustration of a first surgical instrument including a remote operating unit for controlling a second surgical instrument; 
         FIG. 109  is a perspective view of a modular surgical instrument according to various embodiments of the present disclosure; 
         FIG. 110  is an exploded, perspective view of the modular surgical instrument of  FIG. 109 ; 
         FIG. 111  is a schematic depicting the control systems of a modular surgical system according to various embodiments of the present disclosure; 
         FIG. 112  is a flowchart depicting a method for updating a component of a modular surgical system according to various embodiments of the present disclosure; 
         FIG. 113  is a flowchart depicting a method for updating a component of a modular surgical system according to various embodiments of the present disclosure; 
         FIGS. 114A and 114B  are schematics depicting a control circuit according to various embodiments of the present disclosure; 
         FIGS. 115A and 115B  are schematics depicting a control circuit according to various embodiments of the present disclosure; 
         FIG. 116  is a flow chart depicting a method for processing data recorded by a surgical instrument according to various embodiments of the present disclosure; 
         FIG. 117  is a flow chart depicting a method for processing data recorded by a surgical instrument according to various embodiments of the present disclosure; 
         FIGS. 118A-118C  are flow charts depicting various methods for processing data recorded by a surgical instrument according to various embodiments of the present disclosure; 
         FIG. 119  is a schematic depicting a surgical system having wireless communication capabilities according to various embodiments of the present disclosure; 
         FIG. 120  is an elevation view of an external screen depicting an end effector at a surgical site according to various embodiments of the present disclosure; 
         FIG. 121  is an elevation view of the external screen of  FIG. 120  depicting a notification according to various embodiments of the present disclosure; 
         FIG. 122  is an elevation view of the external screen of  FIG. 120  depicting a selection menu according to various embodiments of the present disclosure; 
         FIG. 123  is a partial perspective view of an interchangeable shaft assembly, illustrated with some components removed, including a switch drum illustrated in a first position in accordance with at least one embodiment; 
         FIG. 124  is a perspective view of the interchangeable shaft assembly of  FIG. 123  illustrated with the switch drum rotated into a second position and a torsion spring stretched by the rotation of the switch drum; 
         FIG. 125  is a graph displaying a relationship between the inductance of the spring and the rotation of the switch drum; 
         FIG. 126  is a perspective view of an interchangeable shaft assembly, illustrated with some components removed, in accordance with at least one embodiment; 
         FIG. 127  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 126  including a switch drum illustrated in a first position; 
         FIG. 128  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 126  illustrating the switch drum in a second position; 
         FIG. 129  is a longitudinal cross-sectional view of the interchangeable shaft assembly of  FIG. 126  illustrating an electrical pathway; 
         FIG. 130  is a chart depicting a relationship between the status of an electrical circuit and a mechanical state of the interchangeable shaft assembly of  FIG. 126 ; 
         FIG. 131  is an elevational view of an interchangeable shaft assembly, illustrated with some components removed, including a sensing fork in accordance with at least one embodiment; 
         FIG. 132  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 131  taken along axis  132 - 132  in  FIG. 131  illustrated in a first state; 
         FIG. 133  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 131  taken along axis  132 - 132  in  FIG. 131  illustrated in a second state; 
         FIG. 134  is a partial longitudinal cross-sectional view of an interchangeable shaft assembly in accordance with at least one embodiment; 
         FIG. 135  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 134  taken along axis  135 - 135  in  FIG. 134  illustrated in a first state; 
         FIG. 136  is a cross-sectional view of the interchangeable shaft assembly of  FIG. 134  taken along axis  135 - 135  in  FIG. 134  illustrated in a second state; 
         FIG. 137  is a partial exploded view of an interchangeable shaft assembly and a surgical instrument handle in an unassembled condition in accordance with at least one embodiment; 
         FIG. 138  is a partial cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 137  in a partially assembled condition; 
         FIG. 139  is a partial cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 137  in an assembled condition; 
         FIG. 140  is a cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 137  in the condition of  FIG. 138 ; 
         FIG. 141  is a cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 137  in the condition of  FIG. 139 ; 
         FIG. 142  is a partial exploded view of an interchangeable shaft assembly and a surgical instrument handle in an unassembled condition in accordance with at least one embodiment; 
         FIG. 143  is an elevational view of a firing member and a leaf spring of the interchangeable shaft assembly and the longitudinal drive member of the surgical instrument handle of  FIG. 142  illustrated in an unassembled condition; 
         FIG. 144  is an elevational view of the firing member and leaf spring of the interchangeable shaft assembly and the longitudinal drive member of the surgical instrument handle of  FIG. 142  illustrated in an assembled condition; 
         FIG. 145  is an elevational view of the firing member and leaf spring of the interchangeable shaft assembly and the longitudinal drive member of the surgical instrument handle of  FIG. 142 ; 
         FIG. 146  is a partial cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 142  in the condition of  FIG. 143 ; 
         FIG. 147  is a partial cross-sectional view of the interchangeable shaft assembly and the surgical instrument handle of  FIG. 142  in the condition of  FIG. 144 ; and 
         FIG. 148  is a software module performable by an interchangeable shaft assembly and/or surgical instrument handle in accordance with at least one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Applicant of the present application owns the following patent applications that were filed on Mar. 1, 2013 and which are each herein incorporated by reference in their respective entireties: 
     U.S. patent application Ser. No. 13/782,295, entitled ARTICULATABLE SURGICAL INSTRUMENTS WITH CONDUCTIVE PATHWAYS FOR SIGNAL COMMUNICATION, now U.S. Pat. No. 9,700,309; 
     U.S. patent application Ser. No. 13/782,323, entitled ROTARY POWERED ARTICULATION JOINTS FOR SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,782,169; 
     U.S. patent application Ser. No. 13/782,338, entitled THUMBWHEEL SWITCH ARRANGEMENTS FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2014/0249557; 
     U.S. patent application Ser. No. 13/782,499, entitled ELECTROMECHANICAL SURGICAL DEVICE WITH SIGNAL RELAY ARRANGEMENT, now U.S. Pat. No. 9,358,003; 
     U.S. patent application Ser. No. 13/782,460, entitled MULTIPLE PROCESSOR MOTOR CONTROL FOR MODULAR SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,554,794; 
     U.S. patent application Ser. No. 13/782,358, entitled JOYSTICK SWITCH ASSEMBLIES FOR SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,326,767; 
     U.S. patent application Ser. No. 13/782,481, entitled SENSOR STRAIGHTENED END EFFECTOR DURING REMOVAL THROUGH TROCAR, now U.S. Pat. No. 9,468,438; 
     U.S. patent application Ser. No. 13/782,518, entitled CONTROL METHODS FOR SURGICAL INSTRUMENTS WITH REMOVABLE IMPLEMENT PORTIONS, now U.S. Patent Application Publication No. 2014/0246475; 
     U.S. patent application Ser. No. 13/782,375, entitled ROTARY POWERED SURGICAL INSTRUMENTS WITH MULTIPLE DEGREES OF FREEDOM, now U.S. Pat. No. 9,398,911; and 
     U.S. patent application Ser. No. 13/782,536, entitled SURGICAL INSTRUMENT SOFT STOP, now U.S. Pat. No. 9,307,986, are hereby incorporated by reference in their entireties. 
     Applicant of the present application also owns the following patent applications that were filed on Mar. 14, 2013 and which are each herein incorporated by reference in their respective entireties: 
     U.S. patent application Ser. No. 13/803,097, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, now U.S. Pat. No. 9,687,230; 
     U.S. patent application Ser. No. 13/803,193, entitled CONTROL ARRANGEMENTS FOR A DRIVE MEMBER OF A SURGICAL INSTRUMENT, now U.S. Pat. No. 9,332,987; 
     U.S. patent application Ser. No. 13/803,053, entitled INTERCHANGEABLE SHAFT ASSEMBLIES FOR USE WITH A SURGICAL INSTRUMENT, now U.S. Patent Application Publication No. 2014/0263564; 
     U.S. patent application Ser. No. 13/803,086, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING AN ARTICULATION LOCK, now U.S. Patent Application Publication No. 2014/0263541; 
     U.S. patent application Ser. No. 13/803,210, entitled SENSOR ARRANGEMENTS FOR ABSOLUTE POSITIONING SYSTEM FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2014/0263538; 
     U.S. patent application Ser. No. 13/803,148, entitled MULTI-FUNCTION MOTOR FOR A SURGICAL INSTRUMENT, now U.S. Patent Application Publication No. 2014/0263554; 
     U.S. patent application Ser. No. 13/803,066, entitled DRIVE SYSTEM LOCKOUT ARRANGEMENTS FOR MODULAR SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,629,623; 
     U.S. patent application Ser. No. 13/803,117, entitled ARTICULATION CONTROL SYSTEM FOR ARTICULATABLE SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,351,726; 
     U.S. patent application Ser. No. 13/803,130, entitled DRIVE TRAIN CONTROL ARRANGEMENTS FOR MODULAR SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,351,727; and 
     U.S. patent application Ser. No. 13/803,159, entitled METHOD AND SYSTEM FOR OPERATING A SURGICAL INSTRUMENT, now U.S. Patent Application Publication No. 2014/0277017. 
     Applicant of the present application also owns the following patent applications that were filed on Mar. 26, 2014 and are each herein incorporated by reference in their respective entireties: 
     U.S. patent application Ser. No. 14/226,106, entitled POWER MANAGEMENT CONTROL SYSTEMS FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2015/0272582; 
     U.S. patent application Ser. No. 14/226,099, entitled STERILIZATION VERIFICATION CIRCUIT, now U.S. Patent Application Publication No. 2015/0272581; 
     U.S. patent application Ser. No. 14/226,094, entitled VERIFICATION OF NUMBER OF BATTERY EXCHANGES/PROCEDURE COUNT, now U.S. Patent Application Publication No. 2015/0272581; 
     U.S. patent application Ser. No. 14/226,117, entitled POWER MANAGEMENT THROUGH SLEEP OPTIONS OF SEGMENTED CIRCUIT AND WAKE UP CONTROL, now U.S. Patent Application Publication No. 2015/0272574; 
     U.S. patent application Ser. No. 14/226,075, entitled MODULAR POWERED SURGICAL INSTRUMENT WITH DETACHABLE SHAFT ASSEMBLIES, now U.S. Pat. No. 9,743,929; 
     U.S. patent application Ser. No. 14/226,093, entitled FEEDBACK ALGORITHMS FOR MANUAL BAILOUT SYSTEMS FOR SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2015/0272569; 
     U.S. patent application Ser. No. 14/226,116, entitled SURGICAL INSTRUMENT UTILIZING SENSOR ADAPTATION, now U.S. Patent Application Publication No. 2015/0272571; 
     U.S. patent application Ser. No. 14/226,071, entitled SURGICAL INSTRUMENT CONTROL CIRCUIT HAVING A SAFETY PROCESSOR, now U.S. Pat. No. 9,690,362; 
     U.S. patent application Ser. No. 14/226,097, entitled SURGICAL INSTRUMENT COMPRISING INTERACTIVE SYSTEMS, now U.S. Patent Application Publication No. 2015/0272570; 
     U.S. patent application Ser. No. 14/226,126, entitled INTERFACE SYSTEMS FOR USE WITH SURGICAL INSTRUMENTS, now U.S. Patent Application Publication No. 2015/0272572; 
     U.S. patent application Ser. No. 14/226,133, entitled MODULAR SURGICAL INSTRUMENT SYSTEM, now U.S. Patent Application Publication No. 2015/0272557; 
     U.S. patent application Ser. No. 14/226,081, entitled SYSTEMS AND METHODS FOR CONTROLLING A SEGMENTED CIRCUIT, now U.S. Patent Application Publication No. 2015/0277471; 
     U.S. patent application Ser. No. 14/226,076, entitled POWER MANAGEMENT THROUGH SEGMENTED CIRCUIT AND VARIABLE VOLTAGE PROTECTION, now U.S. Pat. No. 9,733,663; 
     U.S. patent application Ser. No. 14/226,111, entitled SURGICAL STAPLING INSTRUMENT SYSTEM, now U.S. Pat. No. 9,750,499; and 
     U.S. patent application Ser. No. 14/226,125, entitled SURGICAL INSTRUMENT COMPRISING A ROTATABLE SHAFT, now U.S. Patent Application Publication No. 2015/0280384. 
     Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention. 
     Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment”, or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment”, or “in an embodiment”, or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation. Such modifications and variations are intended to be included within the scope of the present invention. 
     The terms “proximal” and “distal” are used herein with reference to a clinician manipulating the handle portion of the surgical instrument. The term “proximal” referring to the portion closest to the clinician and the term “distal” referring to the portion located away from the clinician. It will be further appreciated that, for convenience and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and/or absolute. 
     Various exemplary devices and methods are provided for performing laparoscopic and minimally invasive surgical procedures. However, the person of ordinary skill in the art will readily appreciate that the various methods and devices disclosed herein can be used in numerous surgical procedures and applications including, for example, in connection with open surgical procedures. As the present Detailed Description proceeds, those of ordinary skill in the art will further appreciate that the various instruments disclosed herein can be inserted into a body in any way, such as through a natural orifice, through an incision or puncture hole formed in tissue, etc. The working portions or end effector portions of the instruments can be inserted directly into a patient&#39;s body or can be inserted through an access device that has a working channel through which the end effector and elongated shaft of a surgical instrument can be advanced. 
       FIGS. 1-6  depict a motor-driven surgical cutting and fastening instrument  10  that may or may not be reused. In the illustrated embodiment, the instrument  10  includes a housing  12  that comprises a handle  14  that is configured to be grasped, manipulated and actuated by the clinician. The housing  12  is configured for operable attachment to an interchangeable shaft assembly  200  that has a surgical end effector  300  operably coupled thereto that is configured to perform one or more surgical tasks or procedures. As the present Detailed Description proceeds, it will be understood that the various unique and novel arrangements of the various forms of interchangeable shaft assemblies disclosed herein may also be effectively employed in connection with robotically-controlled surgical systems. Thus, the term “housing” may also encompass a housing or similar portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the interchangeable shaft assemblies disclosed herein and their respective equivalents. The term “frame” may refer to a portion of a handheld surgical instrument. The term “frame” may also represent a portion of a robotically controlled surgical instrument and/or a portion of the robotic system that may be used to operably control a surgical instrument. For example, the interchangeable shaft assemblies disclosed herein may be employed with various robotic systems, instruments, components and methods disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535. U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, is incorporated by reference herein in its entirety. 
     The housing  12  depicted in  FIGS. 1-3  is shown in connection with an interchangeable shaft assembly  200  that includes an end effector  300  that comprises a surgical cutting and fastening device that is configured to operably support a surgical staple cartridge  304  therein. The housing  12  may be configured for use in connection with interchangeable shaft assemblies that include end effectors that are adapted to support different sizes and types of staple cartridges, have different shaft lengths, sizes, and types, etc. In addition, the housing  12  may also be effectively employed with a variety of other interchangeable shaft assemblies including those assemblies that are configured to apply other motions and forms of energy such as, for example, radio frequency (RF) energy, ultrasonic energy and/or motion to end effector arrangements adapted for use in connection with various surgical applications and procedures. Furthermore, the end effectors, shaft assemblies, handles, surgical instruments, and/or surgical instrument systems can utilize any suitable fastener, or fasteners, to fasten tissue. For instance, a fastener cartridge comprising a plurality of fasteners removably stored therein can be removably inserted into and/or attached to the end effector of a shaft assembly. 
       FIG. 1  illustrates the surgical instrument  10  with an interchangeable shaft assembly  200  operably coupled thereto.  FIGS. 2 and 3  illustrate attachment of the interchangeable shaft assembly  200  to the housing  12  or handle  14 . As can be seen in  FIG. 4 , the handle  14  may comprise a pair of interconnectable handle housing segments  16  and  18  that may be interconnected by screws, snap features, adhesive, etc. In the illustrated arrangement, the handle housing segments  16 ,  18  cooperate to form a pistol grip portion  19  that can be gripped and manipulated by the clinician. As will be discussed in further detail below, the handle  14  operably supports a plurality of drive systems therein that are configured to generate and apply various control motions to corresponding portions of the interchangeable shaft assembly that is operably attached thereto. 
     Referring now to  FIG. 4 , the handle  14  may further include a frame  20  that operably supports a plurality of drive systems. For example, the frame  20  can operably support a “first” or closure drive system, generally designated as  30 , which may be employed to apply closing and opening motions to the interchangeable shaft assembly  200  that is operably attached or coupled thereto. In at least one form, the closure drive system  30  may include an actuator in the form of a closure trigger  32  that is pivotally supported by the frame  20 . More specifically, as illustrated in  FIG. 4 , the closure trigger  32  is pivotally coupled to the housing  14  by a pin  33 . Such arrangement enables the closure trigger  32  to be manipulated by a clinician such that when the clinician grips the pistol grip portion  19  of the handle  14 , the closure trigger  32  may be easily pivoted from a starting or “unactuated” position to an “actuated” position and more particularly to a fully compressed or fully actuated position. The closure trigger  32  may be biased into the unactuated position by spring or other biasing arrangement (not shown). In various forms, the closure drive system  30  further includes a closure linkage assembly  34  that is pivotally coupled to the closure trigger  32 . As can be seen in  FIG. 4 , the closure linkage assembly  34  may include a first closure link  36  and a second closure link  38  that are pivotally coupled to the closure trigger  32  by a pin  35 . The second closure link  38  may also be referred to herein as an “attachment member” and include a transverse attachment pin  37 . 
     Still referring to  FIG. 4 , it can be observed that the first closure link  36  may have a locking wall or end  39  thereon that is configured to cooperate with a closure release assembly  60  that is pivotally coupled to the frame  20 . In at least one form, the closure release assembly  60  may comprise a release button assembly  62  that has a distally protruding locking pawl  64  formed thereon. The release button assembly  62  may be pivoted in a counterclockwise direction by a release spring (not shown). As the clinician depresses the closure trigger  32  from its unactuated position towards the pistol grip portion  19  of the handle  14 , the first closure link  36  pivots upward to a point wherein the locking pawl  64  drops into retaining engagement with the locking wall  39  on the first closure link  36  thereby preventing the closure trigger  32  from returning to the unactuated position. See  FIG. 18 . Thus, the closure release assembly  60  serves to lock the closure trigger  32  in the fully actuated position. When the clinician desires to unlock the closure trigger  32  to permit it to be biased to the unactuated position, the clinician simply pivots the closure release button assembly  62  such that the locking pawl  64  is moved out of engagement with the locking wall  39  on the first closure link  36 . When the locking pawl  64  has been moved out of engagement with the first closure link  36 , the closure trigger  32  may pivot back to the unactuated position. Other closure trigger locking and release arrangements may also be employed. 
     Further to the above,  FIGS. 13-15  illustrate the closure trigger  32  in its unactuated position which is associated with an open, or unclamped, configuration of the shaft assembly  200  in which tissue can be positioned between the jaws of the shaft assembly  200 .  FIGS. 16-18  illustrate the closure trigger  32  in its actuated position which is associated with a closed, or clamped, configuration of the shaft assembly  200  in which tissue is clamped between the jaws of the shaft assembly  200 . Upon comparing  FIGS. 14 and 17 , the reader will appreciate that, when the closure trigger  32  is moved from its unactuated position ( FIG. 14 ) to its actuated position ( FIG. 17 ), the closure release button  62  is pivoted between a first position ( FIG. 14 ) and a second position ( FIG. 17 ). The rotation of the closure release button  62  can be referred to as being an upward rotation; however, at least a portion of the closure release button  62  is being rotated toward the circuit board  100 . Referring to  FIG. 4 , the closure release button  62  can include an arm  61  extending therefrom and a magnetic element  63 , such as a permanent magnet, for example, mounted to the arm  61 . When the closure release button  62  is rotated from its first position to its second position, the magnetic element  63  can move toward the circuit board  100 . The circuit board  100  can include at least one sensor configured to detect the movement of the magnetic element  63 . In at least one embodiment, a Hall effect sensor  65 , for example, can be mounted to the bottom surface of the circuit board  100 . The Hall effect sensor  65  can be configured to detect changes in a magnetic field surrounding the Hall effect sensor  65  caused by the movement of the magnetic element  63 . The Hall effect sensor  65  can be in signal communication with a microcontroller  7004  ( FIG. 59 ), for example, which can determine whether the closure release button  62  is in its first position, which is associated with the unactuated position of the closure trigger  32  and the open configuration of the end effector, its second position, which is associated with the actuated position of the closure trigger  32  and the closed configuration of the end effector, and/or any position between the first position and the second position. 
     In at least one form, the handle  14  and the frame  20  may operably support another drive system referred to herein as a firing drive system  80  that is configured to apply firing motions to corresponding portions of the interchangeable shaft assembly attached thereto. The firing drive system may  80  also be referred to herein as a “second drive system”. The firing drive system  80  may employ an electric motor  82 , located in the pistol grip portion  19  of the handle  14 . In various forms, the motor  82  may be a DC brushed driving motor having a maximum rotation of, approximately, 25,000 RPM, for example. In other arrangements, the motor may include a brushless motor, a cordless motor, a synchronous motor, a stepper motor, or any other suitable electric motor. The motor  82  may be powered by a power source  90  that in one form may comprise a removable power pack  92 . As can be seen in  FIG. 4 , for example, the power pack  92  may comprise a proximal housing portion  94  that is configured for attachment to a distal housing portion  96 . The proximal housing portion  94  and the distal housing portion  96  are configured to operably support a plurality of batteries  98  therein. Batteries  98  may each comprise, for example, a Lithium Ion (“LI”) or other suitable battery. The distal housing portion  96  is configured for removable operable attachment to a control circuit board assembly  100  which is also operably coupled to the motor  82 . A number of batteries  98  may be connected in series may be used as the power source for the surgical instrument  10 . In addition, the power source  90  may be replaceable and/or rechargeable. 
     As outlined above with respect to other various forms, the electric motor  82  can include a rotatable shaft (not shown) that operably interfaces with a gear reducer assembly  84  that is mounted in meshing engagement with a with a set, or rack, of drive teeth  122  on a longitudinally-movable drive member  120 . In use, a voltage polarity provided by the power source  90  can operate the electric motor  82  in a clockwise direction wherein the voltage polarity applied to the electric motor by the battery can be reversed in order to operate the electric motor  82  in a counter-clockwise direction. When the electric motor  82  is rotated in one direction, the drive member  120  will be axially driven in the distal direction “DD”. When the motor  82  is driven in the opposite rotary direction, the drive member  120  will be axially driven in a proximal direction “PD”. The handle  14  can include a switch which can be configured to reverse the polarity applied to the electric motor  82  by the power source  90 . As with the other forms described herein, the handle  14  can also include a sensor that is configured to detect the position of the drive member  120  and/or the direction in which the drive member  120  is being moved. 
     Actuation of the motor  82  can be controlled by a firing trigger  130  that is pivotally supported on the handle  14 . The firing trigger  130  may be pivoted between an unactuated position and an actuated position. The firing trigger  130  may be biased into the unactuated position by a spring  132  or other biasing arrangement such that when the clinician releases the firing trigger  130 , it may be pivoted or otherwise returned to the unactuated position by the spring  132  or biasing arrangement. In at least one form, the firing trigger  130  can be positioned “outboard” of the closure trigger  32  as was discussed above. In at least one form, a firing trigger safety button  134  may be pivotally mounted to the closure trigger  32  by pin  35 . The safety button  134  may be positioned between the firing trigger  130  and the closure trigger  32  and have a pivot arm  136  protruding therefrom. See  FIG. 4 . When the closure trigger  32  is in the unactuated position, the safety button  134  is contained in the handle  14  where the clinician cannot readily access it and move it between a safety position preventing actuation of the firing trigger  130  and a firing position wherein the firing trigger  130  may be fired. As the clinician depresses the closure trigger  32 , the safety button  134  and the firing trigger  130  pivot down wherein they can then be manipulated by the clinician. 
     As discussed above, the handle  14  can include a closure trigger  32  and a firing trigger  130 . Referring to  FIGS. 14-18A , the firing trigger  130  can be pivotably mounted to the closure trigger  32 . The closure trigger  32  can include an arm  31  extending therefrom and the firing trigger  130  can be pivotably mounted to the arm  31  about a pivot pin  33 . When the closure trigger  32  is moved from its unactuated position ( FIG. 14 ) to its actuated position ( FIG. 17 ), the firing trigger  130  can descend downwardly, as outlined above. After the safety button  134  has been moved to its firing position, referring primarily to  FIG. 18A , the firing trigger  130  can be depressed to operate the motor of the surgical instrument firing system. In various instances, the handle  14  can include a tracking system, such as system  800 , for example, configured to determine the position of the closure trigger  32  and/or the position of the firing trigger  130 . With primary reference to  FIGS. 14, 17, and 18A , the tracking system  800  can include a magnetic element, such as permanent magnet  802 , for example, which is mounted to an arm  801  extending from the firing trigger  130 . The tracking system  800  can comprise one or more sensors, such as a first Hall effect sensor  803  and a second Hall effect sensor  804 , for example, which can be configured to track the position of the magnet  802 . Upon comparing  FIGS. 14 and 17 , the reader will appreciate that, when the closure trigger  32  is moved from its unactuated position to its actuated position, the magnet  802  can move between a first position adjacent the first Hall effect sensor  803  and a second position adjacent the second Hall effect sensor  804 . Upon comparing  FIGS. 17 and 18A , the reader will further appreciate that, when the firing trigger  130  is moved from an unfired position ( FIG. 17 ) to a fired position ( FIG. 18A ), the magnet  802  can move relative to the second Hall effect sensor  804 . The sensors  803  and  804  can track the movement of the magnet  802  and can be in signal communication with a microcontroller on the circuit board  100 . With data from the first sensor  803  and/or the second sensor  804 , the microcontroller can determine the position of the magnet  802  along a predefined path and, based on that position, the microcontroller can determine whether the closure trigger  32  is in its unactuated position, its actuated position, or a position therebetween. Similarly, with data from the first sensor  803  and/or the second sensor  804 , the microcontroller can determine the position of the magnet  802  along a predefined path and, based on that position, the microcontroller can determine whether the firing trigger  130  is in its unfired position, its fully fired position, or a position therebetween. 
     As indicated above, in at least one form, the longitudinally movable drive member  120  has a rack of teeth  122  formed thereon for meshing engagement with a corresponding drive gear  86  of the gear reducer assembly  84 . At least one form also includes a manually-actuatable “bailout” assembly  140  that is configured to enable the clinician to manually retract the longitudinally movable drive member  120  should the motor  82  become disabled. The bailout assembly  140  may include a lever or bailout handle assembly  142  that is configured to be manually pivoted into ratcheting engagement with teeth  124  also provided in the drive member  120 . Thus, the clinician can manually retract the drive member  120  by using the bailout handle assembly  142  to ratchet the drive member  120  in the proximal direction “PD”. U.S. Patent Application Publication No. 2010/0089970, now U.S. Pat. No. 8,608,045, discloses bailout arrangements and other components, arrangements and systems that may also be employed with the various instruments disclosed herein. U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICAL CUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM, now U.S. Pat. No. 8,608,045, is hereby incorporated by reference in its entirety. 
     Turning now to  FIGS. 1 and 7 , the interchangeable shaft assembly  200  includes a surgical end effector  300  that comprises an elongated channel  302  that is configured to operably support a staple cartridge  304  therein. The end effector  300  may further include an anvil  306  that is pivotally supported relative to the elongated channel  302 . The interchangeable shaft assembly  200  may further include an articulation joint  270  and an articulation lock  350  ( FIG. 8 ) which can be configured to releasably hold the end effector  300  in a desired position relative to a shaft axis SA-SA. Details regarding the construction and operation of the end effector  300 , the articulation joint  270  and the articulation lock  350  are set forth in U.S. patent application Ser. No. 13/803,086, filed Mar. 14, 2013, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING AN ARTICULATION LOCK, now U.S. Patent Application Publication No. 2014/0263541. The entire disclosure of U.S. patent application Ser. No. 13/803,086, filed Mar. 14, 2013, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING AN ARTICULATION LOCK, now U.S. Patent Application Publication No. 2014/0263541, is hereby incorporated by reference herein. As can be seen in  FIGS. 7 and 8 , the interchangeable shaft assembly  200  can further include a proximal housing or nozzle  201  comprised of nozzle portions  202  and  203 . The interchangeable shaft assembly  200  can further include a closure tube  260  which can be utilized to close and/or open the anvil  306  of the end effector  300 . Primarily referring now to  FIGS. 8 and 9 , the shaft assembly  200  can include a spine  210  which can be configured to fixably support a shaft frame portion  212  of the articulation lock  350 . See  FIG. 8 . The spine  210  can be configured to, one, slidably support a firing member  220  therein and, two, slidably support the closure tube  260  which extends around the spine  210 . The spine  210  can also be configured to slidably support a proximal articulation driver  230 . The articulation driver  230  has a distal end  231  that is configured to operably engage the articulation lock  350 . The articulation lock  350  interfaces with an articulation frame  352  that is adapted to operably engage a drive pin (not shown) on the end effector frame (not shown). As indicated above, further details regarding the operation of the articulation lock  350  and the articulation frame may be found in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541. In various circumstances, the spine  210  can comprise a proximal end  211  which is rotatably supported in a chassis  240 . In one arrangement, for example, the proximal end  211  of the spine  210  has a thread  214  formed thereon for threaded attachment to a spine bearing  216  configured to be supported within the chassis  240 . See  FIG. 7 . Such an arrangement facilitates rotatable attachment of the spine  210  to the chassis  240  such that the spine  210  may be selectively rotated about a shaft axis SA-SA relative to the chassis  240 . 
     Referring primarily to  FIG. 7 , the interchangeable shaft assembly  200  includes a closure shuttle  250  that is slidably supported within the chassis  240  such that it may be axially moved relative thereto. As can be seen in  FIGS. 3 and 7 , the closure shuttle  250  includes a pair of proximally-protruding hooks  252  that are configured for attachment to the attachment pin  37  that is attached to the second closure link  38  as will be discussed in further detail below. A proximal end  261  of the closure tube  260  is coupled to the closure shuttle  250  for relative rotation thereto. For example, a U shaped connector  263  is inserted into an annular slot  262  in the proximal end  261  of the closure tube  260  and is retained within vertical slots  253  in the closure shuttle  250 . See  FIG. 7 . Such an arrangement serves to attach the closure tube  260  to the closure shuttle  250  for axial travel therewith while enabling the closure tube  260  to rotate relative to the closure shuttle  250  about the shaft axis SA-SA. A closure spring  268  is journaled on the closure tube  260  and serves to bias the closure tube  260  in the proximal direction “PD” which can serve to pivot the closure trigger into the unactuated position when the shaft assembly is operably coupled to the handle  14 . 
     In at least one form, the interchangeable shaft assembly  200  may further include an articulation joint  270 . Other interchangeable shaft assemblies, however, may not be capable of articulation. As can be seen in  FIG. 7 , for example, the articulation joint  270  includes a double pivot closure sleeve assembly  271 . According to various forms, the double pivot closure sleeve assembly  271  includes an end effector closure sleeve assembly  272  having upper and lower distally projecting tangs  273 ,  274 . An end effector closure sleeve assembly  272  includes a horseshoe aperture  275  and a tab  276  for engaging an opening tab on the anvil  306  in the various manners described in U.S. patent application Ser. No. 13/803,086, filed Mar. 14, 2013, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING AN ARTICULATION LOCK, now U.S. Patent Application Publication No. 2014/0263541, which has been incorporated by reference herein. As described in further detail therein, the horseshoe aperture  275  and tab  276  engage a tab on the anvil when the anvil  306  is opened. An upper double pivot link  277  includes upwardly projecting distal and proximal pivot pins that engage respectively an upper distal pin hole in the upper proximally projecting tang  273  and an upper proximal pin hole in an upper distally projecting tang  264  on the closure tube  260 . A lower double pivot link  278  includes upwardly projecting distal and proximal pivot pins that engage respectively a lower distal pin hole in the lower proximally projecting tang  274  and a lower proximal pin hole in the lower distally projecting tang  265 . See also  FIG. 8 . 
     In use, the closure tube  260  is translated distally (direction “DD”) to close the anvil  306 , for example, in response to the actuation of the closure trigger  32 . The anvil  306  is closed by distally translating the closure tube  260  and thus the shaft closure sleeve assembly  272 , causing it to strike a proximal surface on the anvil  360  in the manner described in the aforementioned reference U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541. As was also described in detail in that reference, the anvil  306  is opened by proximally translating the closure tube  260  and the shaft closure sleeve assembly  272 , causing tab  276  and the horseshoe aperture  275  to contact and push against the anvil tab to lift the anvil  306 . In the anvil-open position, the shaft closure tube  260  is moved to its proximal position. 
     As indicated above, the surgical instrument  10  may further include an articulation lock  350  of the types and construction described in further detail in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541, which can be configured and operated to selectively lock the end effector  300  in position. Such arrangement enables the end effector  300  to be rotated, or articulated, relative to the shaft closure tube  260  when the articulation lock  350  is in its unlocked state. In such an unlocked state, the end effector  300  can be positioned and pushed against soft tissue and/or bone, for example, surrounding the surgical site within the patient in order to cause the end effector  300  to articulate relative to the closure tube  260 . The end effector  300  may also be articulated relative to the closure tube  260  by an articulation driver  230 . 
     As was also indicated above, the interchangeable shaft assembly  200  further includes a firing member  220  that is supported for axial travel within the shaft spine  210 . The firing member  220  includes an intermediate firing shaft portion  222  that is configured for attachment to a distal cutting portion or knife bar  280 . The firing member  220  may also be referred to herein as a “second shaft” and/or a “second shaft assembly”. As can be seen in  FIGS. 8 and 9 , the intermediate firing shaft portion  222  may include a longitudinal slot  223  in the distal end thereof which can be configured to receive a tab  284  on the proximal end  282  of the distal knife bar  280 . The longitudinal slot  223  and the proximal end  282  can be sized and configured to permit relative movement therebetween and can comprise a slip joint  286 . The slip joint  286  can permit the intermediate firing shaft portion  222  of the firing drive  220  to be moved to articulate the end effector  300  without moving, or at least substantially moving, the knife bar  280 . Once the end effector  300  has been suitably oriented, the intermediate firing shaft portion  222  can be advanced distally until a proximal sidewall of the longitudinal slot  223  comes into contact with the tab  284  in order to advance the knife bar  280  and fire the staple cartridge positioned within the channel  302  As can be further seen in  FIGS. 8 and 9 , the shaft spine  210  has an elongate opening or window  213  therein to facilitate assembly and insertion of the intermediate firing shaft portion  222  into the shaft frame  210 . Once the intermediate firing shaft portion  222  has been inserted therein, a top frame segment  215  may be engaged with the shaft frame  212  to enclose the intermediate firing shaft portion  222  and knife bar  280  therein. Further description of the operation of the firing member  220  may be found in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541. 
     Further to the above, the shaft assembly  200  can include a clutch assembly  400  which can be configured to selectively and releasably couple the articulation driver  230  to the firing member  220 . In one form, the clutch assembly  400  includes a lock collar, or sleeve  402 , positioned around the firing member  220  wherein the lock sleeve  402  can be rotated between an engaged position in which the lock sleeve  402  couples the articulation driver  360  to the firing member  220  and a disengaged position in which the articulation driver  360  is not operably coupled to the firing member  200 . When lock sleeve  402  is in its engaged position, distal movement of the firing member  220  can move the articulation driver  360  distally and, correspondingly, proximal movement of the firing member  220  can move the articulation driver  230  proximally. When lock sleeve  402  is in its disengaged position, movement of the firing member  220  is not transmitted to the articulation driver  230  and, as a result, the firing member  220  can move independently of the articulation driver  230 . In various circumstances, the articulation driver  230  can be held in position by the articulation lock  350  when the articulation driver  230  is not being moved in the proximal or distal directions by the firing member  220 . 
     Referring primarily to  FIG. 9 , the lock sleeve  402  can comprise a cylindrical, or an at least substantially cylindrical, body including a longitudinal aperture  403  defined therein configured to receive the firing member  220 . The lock sleeve  402  can comprise diametrically-opposed, inwardly-facing lock protrusions  404  and an outwardly-facing lock member  406 . The lock protrusions  404  can be configured to be selectively engaged with the firing member  220 . More particularly, when the lock sleeve  402  is in its engaged position, the lock protrusions  404  are positioned within a drive notch  224  defined in the firing member  220  such that a distal pushing force and/or a proximal pulling force can be transmitted from the firing member  220  to the lock sleeve  402 . When the lock sleeve  402  is in its engaged position, the second lock member  406  is received within a drive notch  232  defined in the articulation driver  230  such that the distal pushing force and/or the proximal pulling force applied to the lock sleeve  402  can be transmitted to the articulation driver  230 . In effect, the firing member  220 , the lock sleeve  402 , and the articulation driver  230  will move together when the lock sleeve  402  is in its engaged position. On the other hand, when the lock sleeve  402  is in its disengaged position, the lock protrusions  404  may not be positioned within the drive notch  224  of the firing member  220  and, as a result, a distal pushing force and/or a proximal pulling force may not be transmitted from the firing member  220  to the lock sleeve  402 . Correspondingly, the distal pushing force and/or the proximal pulling force may not be transmitted to the articulation driver  230 . In such circumstances, the firing member  220  can be slid proximally and/or distally relative to the lock sleeve  402  and the proximal articulation driver  230 . 
     As can be seen in  FIGS. 8-12 , the shaft assembly  200  further includes a switch drum  500  that is rotatably received on the closure tube  260 . The switch drum  500  comprises a hollow shaft segment  502  that has a shaft boss  504  formed thereon for receive an outwardly protruding actuation pin  410  therein. In various circumstances, the actuation pin  410  extends through a slot  267  into a longitudinal slot  408  provided in the lock sleeve  402  to facilitate axial movement of the lock sleeve  402  when it is engaged with the articulation driver  230 . A rotary torsion spring  420  is configured to engage the boss  504  on the switch drum  500  and a portion of the nozzle housing  203  as shown in  FIG. 10  to apply a biasing force to the switch drum  500 . The switch drum  500  can further comprise at least partially circumferential openings  506  defined therein which, referring to  FIGS. 5 and 6 , can be configured to receive circumferential mounts  204 ,  205  extending from the nozzle halves  202 ,  203  and permit relative rotation, but not translation, between the switch drum  500  and the proximal nozzle  201 . As can be seen in those Figures, the mounts  204  and  205  also extend through openings  266  in the closure tube  260  to be seated in recesses  211  in the shaft spine  210 . However, rotation of the nozzle  201  to a point where the mounts  204 ,  205  reach the end of their respective slots  506  in the switch drum  500  will result in rotation of the switch drum  500  about the shaft axis SA-SA. Rotation of the switch drum  500  will ultimately result in the rotation of eth actuation pin  410  and the lock sleeve  402  between its engaged and disengaged positions. Thus, in essence, the nozzle  201  may be employed to operably engage and disengage the articulation drive system with the firing drive system in the various manners described in further detail in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541. 
     As also illustrated in  FIGS. 8-12 , the shaft assembly  200  can comprise a slip ring assembly  600  which can be configured to conduct electrical power to and/or from the end effector  300  and/or communicate signals to and/or from the end effector  300 , for example. The slip ring assembly  600  can comprise a proximal connector flange  604  mounted to a chassis flange  242  extending from the chassis  240  and a distal connector flange  601  positioned within a slot defined in the shaft housings  202 ,  203 . The proximal connector flange  604  can comprise a first face and the distal connector flange  601  can comprise a second face which is positioned adjacent to and movable relative to the first face. The distal connector flange  601  can rotate relative to the proximal connector flange  604  about the shaft axis SA-SA. The proximal connector flange  604  can comprise a plurality of concentric, or at least substantially concentric, conductors  602  defined in the first face thereof. A connector  607  can be mounted on the proximal side of the connector flange  601  and may have a plurality of contacts (not shown) wherein each contact corresponds to and is in electrical contact with one of the conductors  602 . Such an arrangement permits relative rotation between the proximal connector flange  604  and the distal connector flange  601  while maintaining electrical contact therebetween. The proximal connector flange  604  can include an electrical connector  606  which can place the conductors  602  in signal communication with a shaft circuit board  610  mounted to the shaft chassis  240 , for example. In at least one instance, a wiring harness comprising a plurality of conductors can extend between the electrical connector  606  and the shaft circuit board  610 . The electrical connector  606  may extend proximally through a connector opening  243  defined in the chassis mounting flange  242 . See  FIG. 7 . U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Patent Application Publication No. 2014/0263552, is incorporated by reference in its entirety. U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat. No. 9,345,481, is incorporated by reference in its entirety. Further details regarding slip ring assembly  600  may be found in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541. 
     As discussed above, the shaft assembly  200  can include a proximal portion which is fixably mounted to the handle  14  and a distal portion which is rotatable about a longitudinal axis. The rotatable distal shaft portion can be rotated relative to the proximal portion about the slip ring assembly  600 , as discussed above. The distal connector flange  601  of the slip ring assembly  600  can be positioned within the rotatable distal shaft portion. Moreover, further to the above, the switch drum  500  can also be positioned within the rotatable distal shaft portion. When the rotatable distal shaft portion is rotated, the distal connector flange  601  and the switch drum  500  can be rotated synchronously with one another. In addition, the switch drum  500  can be rotated between a first position and a second position relative to the distal connector flange  601 . When the switch drum  500  is in its first position, the articulation drive system may be operably disengaged from the firing drive system and, thus, the operation of the firing drive system may not articulate the end effector  300  of the shaft assembly  200 . When the switch drum  500  is in its second position, the articulation drive system may be operably engaged with the firing drive system and, thus, the operation of the firing drive system may articulate the end effector  300  of the shaft assembly  200 . When the switch drum  500  is moved between its first position and its second position, the switch drum  500  is moved relative to distal connector flange  601 . In various instances, the shaft assembly  200  can comprise at least one sensor configured to detect the position of the switch drum  500 . Turning now to  FIGS. 11 and 12 , the distal connector flange  601  can comprise a Hall effect sensor  605 , for example, and the switch drum  500  can comprise a magnetic element, such as permanent magnet  505 , for example. The Hall effect sensor  605  can be configured to detect the position of the permanent magnet  505 . When the switch drum  500  is rotated between its first position and its second position, the permanent magnet  505  can move relative to the Hall effect sensor  605 . In various instances, Hall effect sensor  605  can detect changes in a magnetic field created when the permanent magnet  505  is moved. The Hall effect sensor  605  can be in signal communication with the shaft circuit board  610  and/or the handle circuit board  100 , for example. Based on the signal from the Hall effect sensor  605 , a microcontroller on the shaft circuit board  610  and/or the handle circuit board  100  can determine whether the articulation drive system is engaged with or disengaged from the firing drive system. 
     Referring again to  FIGS. 3 and 7 , the chassis  240  includes at least one, and preferably two, tapered attachment portions  244  formed thereon that are adapted to be received within corresponding dovetail slots  702  formed within a distal attachment flange portion  700  of the frame  20 . Each dovetail slot  702  may be tapered or, stated another way, be somewhat V-shaped to seatingly receive the attachment portions  244  therein. As can be further seen in  FIGS. 3 and 7 , a shaft attachment lug  226  is formed on the proximal end of the intermediate firing shaft  222 . As will be discussed in further detail below, when the interchangeable shaft assembly  200  is coupled to the handle  14 , the shaft attachment lug  226  is received in a firing shaft attachment cradle  126  formed in the distal end  125  of the longitudinal drive member  120 . See  FIGS. 3 and 6 . 
     Various shaft assembly embodiments employ a latch system  710  for removably coupling the shaft assembly  200  to the housing  12  and more specifically to the frame  20 . As can be seen in  FIG. 7 , for example, in at least one form, the latch system  710  includes a lock member or lock yoke  712  that is movably coupled to the chassis  240 . In the illustrated embodiment, for example, the lock yoke  712  has a U-shape with two spaced downwardly extending legs  714 . The legs  714  each have a pivot lug  716  formed thereon that are adapted to be received in corresponding holes  245  formed in the chassis  240 . Such arrangement facilitates pivotal attachment of the lock yoke  712  to the chassis  240 . The lock yoke  712  may include two proximally protruding lock lugs  714  that are configured for releasable engagement with corresponding lock detents or grooves  704  in the distal attachment flange  700  of the frame  20 . See  FIG. 3 . In various forms, the lock yoke  712  is biased in the proximal direction by spring or biasing member (not shown). Actuation of the lock yoke  712  may be accomplished by a latch button  722  that is slidably mounted on a latch actuator assembly  720  that is mounted to the chassis  240 . The latch button  722  may be biased in a proximal direction relative to the lock yoke  712 . As will be discussed in further detail below, the lock yoke  712  may be moved to an unlocked position by biasing the latch button the in distal direction which also causes the lock yoke  712  to pivot out of retaining engagement with the distal attachment flange  700  of the frame  20 . When the lock yoke  712  is in “retaining engagement” with the distal attachment flange  700  of the frame  20 , the lock lugs  716  are retainingly seated within the corresponding lock detents or grooves  704  in the distal attachment flange  700 . 
     When employing an interchangeable shaft assembly that includes an end effector of the type described herein that is adapted to cut and fasten tissue, as well as other types of end effectors, it may be desirable to prevent inadvertent detachment of the interchangeable shaft assembly from the housing during actuation of the end effector. For example, in use the clinician may actuate the closure trigger  32  to grasp and manipulate the target tissue into a desired position. Once the target tissue is positioned within the end effector  300  in a desired orientation, the clinician may then fully actuate the closure trigger  32  to close the anvil  306  and clamp the target tissue in position for cutting and stapling. In that instance, the first drive system  30  has been fully actuated. After the target tissue has been clamped in the end effector  300 , it may be desirable to prevent the inadvertent detachment of the shaft assembly  200  from the housing  12 . One form of the latch system  710  is configured to prevent such inadvertent detachment. 
     As can be most particularly seen in  FIG. 7 , the lock yoke  712  includes at least one and preferably two lock hooks  718  that are adapted to contact corresponding lock lug portions  256  that are formed on the closure shuttle  250 . Referring to  FIGS. 13-15 , when the closure shuttle  250  is in an unactuated position (i.e., the first drive system  30  is unactuated and the anvil  306  is open), the lock yoke  712  may be pivoted in a distal direction to unlock the interchangeable shaft assembly  200  from the housing  12 . When in that position, the lock hooks  718  do not contact the lock lug portions  256  on the closure shuttle  250 . However, when the closure shuttle  250  is moved to an actuated position (i.e., the first drive system  30  is actuated and the anvil  306  is in the closed position), the lock yoke  712  is prevented from being pivoted to an unlocked position. See  FIGS. 16-18 . Stated another way, if the clinician were to attempt to pivot the lock yoke  712  to an unlocked position or, for example, the lock yoke  712  was in advertently bumped or contacted in a manner that might otherwise cause it to pivot distally, the lock hooks  718  on the lock yoke  712  will contact the lock lugs  256  on the closure shuttle  250  and prevent movement of the lock yoke  712  to an unlocked position. 
     Attachment of the interchangeable shaft assembly  200  to the handle  14  will now be described with reference to  FIG. 3 . To commence the coupling process, the clinician may position the chassis  240  of the interchangeable shaft assembly  200  above or adjacent to the distal attachment flange  700  of the frame  20  such that the tapered attachment portions  244  formed on the chassis  240  are aligned with the dovetail slots  702  in the frame  20 . The clinician may then move the shaft assembly  200  along an installation axis IA that is perpendicular to the shaft axis SA-SA to seat the attachment portions  244  in “operable engagement” with the corresponding dovetail receiving slots  702 . In doing so, the shaft attachment lug  226  on the intermediate firing shaft  222  will also be seated in the cradle  126  in the longitudinally movable drive member  120  and the portions of pin  37  on the second closure link  38  will be seated in the corresponding hooks  252  in the closure yoke  250 . As used herein, the term “operable engagement” in the context of two components means that the two components are sufficiently engaged with each other so that upon application of an actuation motion thereto, the components may carry out their intended action, function and/or procedure. 
     As discussed above, at least five systems of the interchangeable shaft assembly  200  can be operably coupled with at least five corresponding systems of the handle  14 . A first system can comprise a frame system which couples and/or aligns the frame or spine of the shaft assembly  200  with the frame  20  of the handle  14 . Another system can comprise a closure drive system  30  which can operably connect the closure trigger  32  of the handle  14  and the closure tube  260  and the anvil  306  of the shaft assembly  200 . As outlined above, the closure tube attachment yoke  250  of the shaft assembly  200  can be engaged with the pin  37  on the second closure link  38 . Another system can comprise the firing drive system  80  which can operably connect the firing trigger  130  of the handle  14  with the intermediate firing shaft  222  of the shaft assembly  200 . As outlined above, the shaft attachment lug  226  can be operably connected with the cradle  126  of the longitudinal drive member  120 . Another system can comprise an electrical system which can signal to a controller in the handle  14 , such as microcontroller, for example, that a shaft assembly, such as shaft assembly  200 , for example, has been operably engaged with the handle  14  and/or, two, conduct power and/or communication signals between the shaft assembly  200  and the handle  14 . For instance, the shaft assembly  200  can include an electrical connector  4010  that is operably mounted to the shaft circuit board  610 . The electrical connector  4010  is configured for mating engagement with a corresponding electrical connector  4000  on the handle control board  100 . Further details regaining the circuitry and control systems may be found in U.S. patent application Ser. No. 13/803,086, now U.S. Patent Application Publication No. 2014/0263541, the entire disclosure of which was previously incorporated by reference herein. The fifth system may consist of the latching system for releasably locking the shaft assembly  200  to the handle  14 . 
     Referring again to  FIGS. 2 and 3 , the handle  14  can include an electrical connector  4000  comprising a plurality of electrical contacts. Turning now to  FIG. 59 , the electrical connector  4000  can comprise a first contact  4001   a , a second contact  4001   b , a third contact  4001   c , a fourth contact  4001   d , a fifth contact  4001   e , and a sixth contact  4001   f , for example. While the illustrated embodiment utilizes six contacts, other embodiments are envisioned which may utilize more than six contacts or less than six contacts. As illustrated in  FIG. 59 , the first contact  4001   a  can be in electrical communication with a transistor  4008 , contacts  4001   b - 4001   e  can be in electrical communication with a microcontroller  7004 , and the sixth contact  4001   f  can be in electrical communication with a ground. In certain circumstances, one or more of the electrical contacts  4001   b - 4001   e  may be in electrical communication with one or more output channels of the microcontroller  7004  and can be energized, or have a voltage potential applied thereto, when the handle  1042  is in a powered state. In some circumstances, one or more of the electrical contacts  4001   b - 4001   e  may be in electrical communication with one or more input channels of the microcontroller  7004  and, when the handle  14  is in a powered state, the microcontroller  7004  can be configured to detect when a voltage potential is applied to such electrical contacts. When a shaft assembly, such as shaft assembly  200 , for example, is assembled to the handle  14 , the electrical contacts  4001   a - 4001   f  may not communicate with each other. When a shaft assembly is not assembled to the handle  14 , however, the electrical contacts  4001   a - 4001   f  of the electrical connector  4000  may be exposed and, in some circumstances, one or more of the contacts  4001   a - 4001   f  may be accidentally placed in electrical communication with each other. Such circumstances can arise when one or more of the contacts  4001   a - 4001   f  come into contact with an electrically conductive material, for example. When this occurs, the microcontroller  7004  can receive an erroneous input and/or the shaft assembly  200  can receive an erroneous output, for example. To address this issue, in various circumstances, the handle  14  may be unpowered when a shaft assembly, such as shaft assembly  200 , for example, is not attached to the handle  14 . In other circumstances, the handle  1042  can be powered when a shaft assembly, such as shaft assembly  200 , for example, is not attached thereto. In such circumstances, the microcontroller  7004  can be configured to ignore inputs, or voltage potentials, applied to the contacts in electrical communication with the microcontroller  7004 , i.e., contacts  4001   b - 4001   e , for example, until a shaft assembly is attached to the handle  14 . Even though the microcontroller  7004  may be supplied with power to operate other functionalities of the handle  14  in such circumstances, the handle  14  may be in a powered-down state. In a way, the electrical connector  4000  may be in a powered-down state as voltage potentials applied to the electrical contacts  4001   b - 4001   e  may not affect the operation of the handle  14 . The reader will appreciate that, even though contacts  4001   b - 4001   e  may be in a powered-down state, the electrical contacts  4001   a  and  4001   f , which are not in electrical communication with the microcontroller  7004 , may or may not be in a powered-down state. For instance, sixth contact  4001   f  may remain in electrical communication with a ground regardless of whether the handle  14  is in a powered-up or a powered-down state. Furthermore, the transistor  4008 , and/or any other suitable arrangement of transistors, such as transistor  4010 , for example, and/or switches may be configured to control the supply of power from a power source  4004 , such as a battery  90  within the handle  14 , for example, to the first electrical contact  4001   a  regardless of whether the handle  14  is in a powered-up or a powered-down state. In various circumstances, the shaft assembly  200 , for example, can be configured to change the state of the transistor  4008  when the shaft assembly  200  is engaged with the handle  14 . In certain circumstances, further to the below, a Hall effect sensor  4002  can be configured to switch the state of transistor  4010  which, as a result, can switch the state of transistor  4008  and ultimately supply power from power source  4004  to first contact  4001   a . In this way, both the power circuits and the signal circuits to the connector  4000  can be powered down when a shaft assembly is not installed to the handle  14  and powered up when a shaft assembly is installed to the handle  14 . 
     In various circumstances, referring again to  FIG. 59 , the handle  14  can include the Hall effect sensor  4002 , for example, which can be configured to detect a detectable element, such as a magnetic element  4007  ( FIG. 3 ), for example, on a shaft assembly, such as shaft assembly  200 , for example, when the shaft assembly is coupled to the handle  14 . The Hall effect sensor  4002  can be powered by a power source  4006 , such as a battery, for example, which can, in effect, amplify the detection signal of the Hall effect sensor  4002  and communicate with an input channel of the microcontroller  7004  via the circuit illustrated in  FIG. 59 . Once the microcontroller  7004  has a received an input indicating that a shaft assembly has been at least partially coupled to the handle  14 , and that, as a result, the electrical contacts  4001   a - 4001   f  are no longer exposed, the microcontroller  7004  can enter into its normal, or powered-up, operating state. In such an operating state, the microcontroller  7004  will evaluate the signals transmitted to one or more of the contacts  4001   b - 4001   e  from the shaft assembly and/or transmit signals to the shaft assembly through one or more of the contacts  4001   b - 4001   e  in normal use thereof. In various circumstances, the shaft assembly  1200  may have to be fully seated before the Hall effect sensor  4002  can detect the magnetic element  4007 . While a Hall effect sensor  4002  can be utilized to detect the presence of the shaft assembly  200 , any suitable system of sensors and/or switches can be utilized to detect whether a shaft assembly has been assembled to the handle  14 , for example. In this way, further to the above, both the power circuits and the signal circuits to the connector  4000  can be powered down when a shaft assembly is not installed to the handle  14  and powered up when a shaft assembly is installed to the handle  14 . 
     In various embodiments, any number of magnetic sensing elements may be employed to detect whether a shaft assembly has been assembled to the handle  14 , for example. For example, the technologies used for magnetic field sensing include search coil, fluxgate, optically pumped, nuclear precession, SQUID, Hall-effect, anisotropic magnetoresistance, giant magnetoresistance, magnetic tunnel junctions, giant magnetoimpedance, magnetostrictive/piezoelectric composites, magnetodiode, magnetotransistor, fiber optic, magnetooptic, and microelectromechanical systems-based magnetic sensors, among others. 
     Referring to  FIG. 59 , the microcontroller  7004  may generally comprise a microprocessor (“processor”) and one or more memory units operationally coupled to the processor. By executing instruction code stored in the memory, the processor may control various components of the surgical instrument, such as the motor, various drive systems, and/or a user display, for example. The microcontroller  7004  may be implemented using integrated and/or discrete hardware elements, software elements, and/or a combination of both. Examples of integrated hardware elements may include processors, microprocessors, microcontrollers, integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate arrays (FPGA), logic gates, registers, semiconductor devices, chips, microchips, chip sets, microcontrollers, system-on-chip (SoC), and/or system-in-package (SIP). Examples of discrete hardware elements may include circuits and/or circuit elements such as logic gates, field effect transistors, bipolar transistors, resistors, capacitors, inductors, and/or relays. In certain instances, the microcontroller  7004  may include a hybrid circuit comprising discrete and integrated circuit elements or components on one or more substrates, for example. 
     Referring to  FIG. 59 , the microcontroller  7004  may be an LM 4F230H5QR, available from Texas Instruments, for example. In certain instances, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available. Other microcontrollers may be readily substituted for use with the present disclosure. Accordingly, the present disclosure should not be limited in this context. 
     As discussed above, the handle  14  and/or the shaft assembly  200  can include systems and configurations configured to prevent, or at least reduce the possibility of, the contacts of the handle electrical connector  4000  and/or the contacts of the shaft electrical connector  4010  from becoming shorted out when the shaft assembly  200  is not assembled, or completely assembled, to the handle  14 . Referring to  FIG. 3 , the handle electrical connector  4000  can be at least partially recessed within a cavity  4009  defined in the handle frame  20 . The six contacts  4001   a - 4001   f  of the electrical connector  4000  can be completely recessed within the cavity  4009 . Such arrangements can reduce the possibility of an object accidentally contacting one or more of the contacts  4001   a - 4001   f . Similarly, the shaft electrical connector  4010  can be positioned within a recess defined in the shaft chassis  240  which can reduce the possibility of an object accidentally contacting one or more of the contacts  4011   a - 4011   f  of the shaft electrical connector  4010 . With regard to the particular embodiment depicted in  FIG. 3 , the shaft contacts  4011   a - 4011   f  can comprise male contacts. In at least one embodiment, each shaft contact  4011   a - 4011   f  can comprise a flexible projection extending therefrom which can be configured to engage a corresponding handle contact  4001   a - 4001   f , for example. The handle contacts  4001   a - 4001   f  can comprise female contacts. In at least one embodiment, each handle contact  4001   a - 4001   f  can comprise a flat surface, for example, against which the male shaft contacts  4001   a - 4001   f  can wipe, or slide, against and maintain an electrically conductive interface therebetween. In various instances, the direction in which the shaft assembly  200  is assembled to the handle  14  can be parallel to, or at least substantially parallel to, the handle contacts  4001   a - 4001   f  such that the shaft contacts  4011   a - 4011   f  slide against the handle contacts  4001   a - 4001   f  when the shaft assembly  200  is assembled to the handle  14 . In various alternative embodiments, the handle contacts  4001   a - 4001   f  can comprise male contacts and the shaft contacts  4011   a - 4011   f  can comprise female contacts. In certain alternative embodiments, the handle contacts  4001   a - 4001   f  and the shaft contacts  4011   a - 4011   f  can comprise any suitable arrangement of contacts. 
     In various instances, the handle  14  can comprise a connector guard configured to at least partially cover the handle electrical connector  4000  and/or a connector guard configured to at least partially cover the shaft electrical connector  4010 . A connector guard can prevent, or at least reduce the possibility of, an object accidentally touching the contacts of an electrical connector when the shaft assembly is not assembled to, or only partially assembled to, the handle. A connector guard can be movable. For instance, the connector guard can be moved between a guarded position in which it at least partially guards a connector and an unguarded position in which it does not guard, or at least guards less of, the connector. In at least one embodiment, a connector guard can be displaced as the shaft assembly is being assembled to the handle. For instance, if the handle comprises a handle connector guard, the shaft assembly can contact and displace the handle connector guard as the shaft assembly is being assembled to the handle. Similarly, if the shaft assembly comprises a shaft connector guard, the handle can contact and displace the shaft connector guard as the shaft assembly is being assembled to the handle. In various instances, a connector guard can comprise a door, for example. In at least one instance, the door can comprise a beveled surface which, when contacted by the handle or shaft, can facilitate the displacement of the door in a certain direction. In various instances, the connector guard can be translated and/or rotated, for example. In certain instances, a connector guard can comprise at least one film which covers the contacts of an electrical connector. When the shaft assembly is assembled to the handle, the film can become ruptured. In at least one instance, the male contacts of a connector can penetrate the film before engaging the corresponding contacts positioned underneath the film. 
     As described above, the surgical instrument can include a system which can selectively power-up, or activate, the contacts of an electrical connector, such as the electrical connector  4000 , for example. In various instances, the contacts can be transitioned between an unactivated condition and an activated condition. In certain instances, the contacts can be transitioned between a monitored condition, a deactivated condition, and an activated condition. For instance, the microcontroller  7004 , for example, can monitor the contacts  4001   a - 4001   f  when a shaft assembly has not been assembled to the handle  14  to determine whether one or more of the contacts  4001   a - 4001   f  may have been shorted. The microcontroller  7004  can be configured to apply a low voltage potential to each of the contacts  4001   a - 4001   f  and assess whether only a minimal resistance is present at each of the contacts. Such an operating state can comprise the monitored condition. In the event that the resistance detected at a contact is high, or above a threshold resistance, the microcontroller  7004  can deactivate that contact, more than one contact, or, alternatively, all of the contacts. Such an operating state can comprise the deactivated condition. If a shaft assembly is assembled to the handle  14  and it is detected by the microcontroller  7004 , as discussed above, the microcontroller  7004  can increase the voltage potential to the contacts  4001   a - 4001   f  Such an operating state can comprise the activated condition. 
     The various shaft assemblies disclosed herein may employ sensors and various other components that require electrical communication with the controller in the housing. These shaft assemblies generally are configured to be able to rotate relative to the housing necessitating a connection that facilitates such electrical communication between two or more components that may rotate relative to each other. When employing end effectors of the types disclosed herein, the connector arrangements must be relatively robust in nature while also being somewhat compact to fit into the shaft assembly connector portion. 
       FIGS. 19-22  depict one form of electric coupler or slip ring connector  1600  that may be employed with, for example an interchangeable shaft assembly  1200  or a variety of other applications that require electrical connections between components that rotate relative to each other. The shaft assembly  1200  may be similar to shaft assembly  200  described herein and include a closure tube or outer shaft  1260  and a proximal nozzle  1201  (the upper half of nozzle  1201  is omitted for clarity). In the illustrated example, the outer shaft  1260  is mounted on a shaft spine  1210  such that the outer tube  1260  may be selectively axially movable thereon. The proximal ends of the shaft spine  1210  and the outer tube  1260  may be rotatably coupled to a chassis  1240  for rotation relative thereto about a shaft axis SA-SA. As was discussed above, the proximal nozzle  1201  may include mounts or mounting lugs  1204  ( FIG. 20 ) that protrude inwardly from the nozzle portions and extend through corresponding openings  1266  in the outer tube  1260  to be seated in corresponding recesses  1211  in the shaft spine  1210 . Thus, to rotate the outer shaft  1260  and spine shaft  1210  and presumably an end effector (not shown) coupled thereto about the shaft axis SA-SA relative to the chassis  1240 , the clinician simply rotates the nozzle  1201  as represented by arrows “R” in  FIG. 19 . 
     When sensors are employed at the end effector or at locations within or on the shaft assembly for example, conductors such as wires and/or traces (not shown) may be received or mounted within the outer tube  1260  or could even be routed along the outer tube  1260  from the sensors to a distal electrical component  1800  mounted within the nozzle  1201 . Thus, the distal electrical component  1800  is rotatable with the nozzle  1201  about the shaft axis SA-SA. In the embodiment illustrated in  FIG. 20 , the electrical component  1800  comprises a connector, battery, etc. that includes contacts  1802 ,  1804 ,  1806 , and  1808  that are laterally displaced from each other. 
     The slip ring connector  1600  further includes a mounting member  1610  that includes a cylindrical body portion  1612  that defines an annular mounting surface  1613 . A distal flange  1614  may be formed on at least one end of the cylindrical body portion  1612 . The body portion  1612  of the mounting member  1610  is sized to be non-rotatably mounted on a mounting hub  1241  on the chassis  1240 . In the illustrated embodiment, one distal flange  1614  is provided on one end of the body portion  1612 . A second flange  1243  is formed on the chassis  1240  such that when the body portion  1612  is fixedly (non-rotatably) mounted thereon, the second flange  1243  abuts the proximal end of the body portion  1612 . 
     The slip ring connector  1600  also employs a unique and novel annular circuit trace assembly  1620  that is wrapped around the annular mounting surface  1613  of the body portion  1612  such that it is received between the first and second flanges  1614  and  1243 . Referring now to  FIGS. 21 and 22 , the circuit trace assembly  1620  may comprise an adhesive-backed flexible substrate  1622  that may be wrapped around the circumference of the body portion  1612  (i.e., the annular mounting surface  1613 ). Prior to being wrapped around the body portion  1612 , the flexible substrate  1622  may have a “T-shape” with a first annular portion  1624  and a lead portion  1626 . As can also be seen in  FIGS. 19-21 , the circuit trace assembly  1620  may further include circuit traces  1630 ,  1640 ,  1650 ,  1660  that may comprise, for example, electrically-conductive gold-plated traces. However, other electrically-conductive materials may also be used. Each electrically-conductive circuit trace includes an “annular portion” that will form an annular part of the trace when the substrate is wrapped around the body portion  1612  as well as another “lead portion” that extends transversely from or perpendicular from the annular portion. More specifically, referring to  FIG. 22 , first electrically-conductive circuit trace  1630  has a first annular portion  1632  and first lead portion  1634 . The second electrically-conductive circuit trace  1640  has a second annular portion  1642  and a second lead portion  1644  extending transversely or perpendicularly therefrom. The third electrically conductive circuit trace  1650  has a third annular portion  1652  and a third lead portion  1654  extending transversely or perpendicularly therefrom. The fourth electrically-conductive circuit trace has a fourth annular portion  1662  and a fourth lead portion  1664  extending transversely or perpendicularly therefrom. The electrically-conductive circuit traces  1630 ,  1640 ,  1650 ,  1660  may be applied to the flexible substrate  1622  while the substrate is in a planar orientation (i.e., prior to being wrapped onto the annular body portion  1612  of the mounting member  1610 ) using conventional manufacturing techniques. As can be seen in  FIG. 22 , the annular portions  1632 ,  1642 ,  1652 ,  1662  are laterally displaced from each other. Likewise, the lead portions  1634 ,  1644 ,  1654 ,  1664  are laterally displaced from each other. 
     When the circuit trace assembly  1620  is wrapped around the annular mounting surface  1613  and attached thereto by adhesive, double-stick tape, etc., the ends of the portion of the substrate that contains the annular portions  1632 ,  1642 ,  1652 ,  1664  are butted together such that the annular portions  1632 ,  1642 ,  1652 ,  1664  form discrete continuous annular electrically-conductive paths  1636 ,  1646 ,  1656 ,  1666 , respectively that extend around the shaft axis SA-SA. Thus, the electrically-conductive paths  1636 ,  1646 ,  1656 , and  1666  are laterally or axially displaced from each other along the shaft axis SA-SA. The lead portion  1626  may extend through a slot  1245  in the flange  1243  and be electrically coupled to a circuit board (see e.g.,  FIG. 7 —circuit board  610 ) or other suitable electrical component(s). 
     In the depicted embodiment for example, the electrical component  1800  is mounted within the nozzle  1261  for rotation about the mounting member  1610  such that: contact  1802  is in constant electrical contact with the first annular electrically-conductive path  1636 ; contact  1804  is in constant electrical contact with the second annular electrically-conductive path  1646 ; contact  1806  is in constant electrical contact with the third annular electrically-conductive path  1656 ; and contact  1808  is in constant electrical contact with the fourth electrically-conductive path  1666 . It will be understood however, that the various advantages of the slip ring connector  1600  may also be obtained in applications wherein the mounting member  1610  is supported for rotation about the shaft axis SA-SA and the electrical component  1800  is fixedly mounted relative thereto. It will be further appreciated that the slip ring connector  1600  may be effectively employed in connection with a variety of different components and applications outside the field of surgery wherein it is desirable to provide electrical connections between components that rotate relative to each other. 
     The slip ring connector  1600  comprises a radial slip ring that provides a conductive contact means of passing signal(s) and power to and from any radial position and after shaft rotation. In applications wherein the electrical component comprises a battery contact, the battery contact position can be situated relative to the mounting member to minimize any tolerance stack up between those components. The coupler arrangement may represent a low cost coupling arrangement that can be assembled with minimal manufacturing costs. The gold plated traces may also minimize the likelihood of corrosion. The unique and novel contact arrangement facilitates complete clockwise and counterclockwise rotation about the shaft axis SA-SA while remaining in electrical contact with the corresponding annular electrically-conductive paths. 
       FIGS. 23-25  depict one form of electric coupler or slip ring connector  1600 ′ that may be employed with, for example an interchangeable shaft assembly  1200 ′ or a variety of other applications that require electrical connections between components that rotate relative to each other. The shaft assembly  1200 ′ may be similar to shaft assembly  1200  described herein and include a closure tube or outer shaft  1260  and a proximal nozzle  1201  (the upper half of nozzle  1201  is omitted for clarity). In the illustrated example, the outer shaft  1260  is mounted on a shaft spine  1210  such that the outer tube  1260  may be selectively axially movable thereon. The proximal ends of the shaft spine  1210  and the outer tube  1260  may be rotatably coupled to a chassis  1240 ′ for rotation relative thereto about a shaft axis SA-SA. As was discussed above, the proximal nozzle  1201  may include mounts or mounting lugs that protrude inwardly from the nozzle portions and extend through corresponding openings  1266  in the outer tube  1260  to be seated in corresponding recesses  1211  in the shaft spine  1210 . Thus, to rotate the outer shaft  1260  and spine shaft  1210  and presumably an end effector (not shown) coupled thereto about the shaft axis SA-SA relative to the chassis  1240 ′, the clinician simply rotates the nozzle  1201  as represented by arrows “R” in  FIG. 23 . 
     When sensors are employed at the end effector or at locations within or on the shaft assembly for example, conductors such as wires and/or traces (not shown) may be received or mounted within the outer tube  1260  or could even be routed along the outer tube  1260  from the sensors to a distal electrical component  1800 ′ mounted within the nozzle  1201 . Thus, the distal electrical component  1800 ′ is rotatable with the nozzle  1201  and the wires/traces attached thereto. In the embodiment illustrated in  FIG. 23 , the electrical component  1800  comprises a connector, battery, etc. that includes contacts  1802 ′,  1804 ′,  1806 ′,  1808 ′ that are laterally displaced from each other. 
     The slip ring connector  1600 ′ further includes a laminated slip ring assembly  1610 ′ that is fabricated from a plurality of conductive rings that are laminated together. More specifically and with reference to  FIG. 25 , one form of slip ring assembly  1610 ′ may comprise a first non-electrically conductive flange  1670  that forms a distal end of the slip ring assembly  1610 ′. The flange  1670  may be fabricated from a high-heat resistant material, for example. A first electrically conductive ring  1680  is positioned immediately adjacent the first flange  1670 . The first electrically conductive ring  1680  may comprise a first copper ring  1681  that has a first gold plating  1682  thereon. A second non-electrically conductive ring  1672  is adjacent to the first electrically-conductive ring  1680 . A second electrically-conductive ring  1684  is adjacent to the second non-electrically-conductive ring  1672 . The second electrically-conductive ring  1684  may comprise a second copper ring  1685  that has a second gold plating  1686  thereon. A third non-electrically-conductive ring  1674  is adjacent to the second electrically-conductive ring  1684 . A third electrically conductive ring  1688  is adjacent to the third non-electrically conductive ring  1674 . The third electrically conductive ring  1688  may comprise a third copper ring  1689  that has a third gold plating  1690  thereon. A fourth non-electrically conductive ring  1676  is adjacent to the third electrically-conductive ring  1688 . A fourth electrically conductive ring  1692  is adjacent to the fourth non-electrically-conductive ring  1676 . The fourth electrically-conductive ring  1692  is adjacent to the fourth non-electrically conductive ring  1676 . A fifth non-electrically conductive ring  1678  is adjacent to the fourth electrically-conductive ring  1692  and forms the proximal end of the mounting member  1610 ′. The non-electrically conductive rings  1670 ,  1672 ,  1674 ,  1676 , and  1678  may be fabricated from the same material. The first electrically-conductive ring  1680  forms a first annular electrically-conductive pathway  1700 . The second electrically-conductive ring  1682  forms a second annular electrically-conductive pathway  1702  that is laterally or axially spaced from the first annular electrically-conductive pathway  1700 . The third electrically-conductive ring  1688  forms a third annular electrically conductive pathway  1704  that is laterally or axially spaced from the second annular electrically-conductive pathway  1702 . The fourth electrically-conductive ring  1692  forms a fourth annular electrically-conductive pathway  1706  that is laterally or axially spaced from the third annular electrically-conductive pathway  1704 . The slip ring assembly  1610 ′ comprises a one piece molded high temperature resistant, non-conductive material with molded in channels for electromagnetic forming (EMF—Magneformed) copper rings. 
     As can be seen in  FIG. 24 , the slip ring connector  1600 ′ further includes a non-conductive transverse mounting member  1720  that is adapted to be inserted into axially-aligned notches  1710  in each of the rings  1670 ,  1680 ,  1672 ,  1684 ,  1674 ,  1688 ,  1676 ,  1692 , and  1678 . The transverse mounting member  1720  has a first circuit trace  1722  thereon that is adapted for electrical contact with the first annular electrically-conductive pathway  1700  when the transverse mounting member  1672  is mounted within the notches  1710 . Likewise, a second circuit trace  1724  is printed on the transverse mounting member  1720  and is configured for electrical contact with the second annular electrically conductive pathway  1702 . A third circuit trace  1726  is printed on the transverse mounting member  1720  and is configured for electrical contact with the third annular electrically-conductive pathway  1704 . A fourth circuit trace  1728  is printed on the transverse mounting member  1720  and is configured for electrical contact with the fourth annular electrically-conductive pathway  1706 . 
     In the arrangement depicted in  FIGS. 23-25 , the slip ring assembly  1610 ′ is configured to be fixedly (non-rotatably) received on a mounting hub  1241 ′ on the chassis  1240 ′. The transverse mounting member  1720  is received within groove  1243 ′ formed in the mounting hub  1241 ′ which acts as a keyway for the transverse mounting member  1720  and which serves to prevent the slip ring assembly  1610 ′ from rotating relative to the mounting hub  1241 ′. 
     In the depicted embodiment for example, the electrical component  1800 ′ is mounted within the nozzle  1201  for rotation about the slip ring assembly  1610 ′ such that: contact  1802 ′ is in constant electrical contact with the first annular electrically-conductive path  1700 ; contact  1804 ′ is in constant electrical contact with the second annular electrically-conductive path  1702 ; contact  1806 ′ is in constant electrical contact with the third annular electrically-conductive path  1704 ; and contact  1808 ′ is in constant electrical contact with the fourth electrically-conductive path  1706 . It will be understood however, that the various advantages of the slip ring connector  1600 ′ may also be obtained in applications wherein the slip ring assembly  1610 ′ is supported for rotation about the shaft axis SA-SA and the electrical component  1800 ′ is fixedly mounted relative thereto. It will be further appreciated that the slip ring connector  1600 ′ may be effectively employed in connection with a variety of different components and applications outside the field of surgery wherein it is desirable to provide electrical connections between components that rotate relative to each other. 
     The slip ring connector  1600 ′ comprises a radial slip ring that provides a conductive contact means of passing signal(s) and power to and from any radial position and after shaft rotation. In applications wherein the electrical component comprises a battery contact, the battery contact position can be situated relative to the mounting member to minimize any tolerance stack-up between those components. The slip ring connector  1600 ′ represents a low cost coupling arrangement that can be assembled with minimal manufacturing costs. The gold plated traces may also minimize the likelihood of corrosion. The unique and novel contact arrangement facilitates complete clockwise and counterclockwise rotation about the shaft axis while remaining in electrical contact with the corresponding annular electrically-conductive paths. 
       FIGS. 26-30  depict another form of electric coupler or slip ring connector  1600 ″ that may be employed with, for example an interchangeable shaft assembly  1200 ″ or a variety of other applications that require electrical connections between components that rotate relative to each other. The shaft assembly  1200 ″ may be similar to shaft assemblies  1200  and/or  1200 ′ described herein except for the differences noted below. The shaft assembly  1200 ″ may include a closure tube or outer shaft  1260  and a proximal nozzle  1201  (the upper half of nozzle  1201  is omitted for clarity). In the illustrated example, the outer shaft  1260  is mounted on a shaft spine  1210  such that the outer tube  1260  may be selectively axially movable thereon. The proximal ends of the shaft spine  1210  and the outer tube  1260  may be rotatably coupled to a chassis  1240 ″ for rotation relative thereto about a shaft axis SA-SA. As was discussed above, the proximal nozzle  1201  may include mounts or mounting lugs that protrude inwardly from the nozzle portions and extend through corresponding openings  1266  in the outer tube  1260  to be seated in corresponding recesses  1211  in the shaft spine  1210 . Thus, to rotate the outer shaft  1260  and spine shaft  1210  and presumably an end effector (not shown) coupled thereto about the shaft axis SA-SA relative to the chassis  1240 ″, the clinician simply rotates the nozzle  1201 . 
     When sensors are employed at the end effector or at locations within or on the shaft assembly for example, conductors such as wires and/or traces (not shown) may be received or mounted within the outer tube  1260  or could even be routed along the outer tube  1260  from the sensors to a distal electrical component  1800 ′″ mounted within the nozzle  1201 . In the illustrated embodiment, for example, the electrical component  1800 ″ is mounted in the nozzle  1201  such that it is substantially aligned with the shaft axis SA-SA. The distal electrical component  1800 ″ is rotatable about the shaft axis SA-SA with the nozzle  1201  and the wires/traces attached thereto. The electrical component  1800 ″ may comprise a connector, a battery, etc. that includes four contacts  1802 ″,  1804 ″,  1806 ″,  1808 ″ that are laterally displaced from each other. 
     The slip ring connector  1600 ″ further includes a slip ring assembly  1610 ″ that includes a base ring  1900  that is fabricated from a non-electrically conductive material and has a central mounting bore  1902  therethrough. The mounting bore  1902  has a flat surface  1904  and is configured for non-rotational attachment to a mounting flange assembly  1930  that is supported at a distal end of the chassis  1240 ″. A distal side  1905  of the base ring  1900  has a series of concentric electrical-conductive rings  1906 ,  1908 ,  1910 , and  1912  attached or laminated thereto. The rings  1906 ,  1908 ,  1910 , and  1912  may be attached to the base ring  1900  by any suitable method. 
     The base ring  1900  may further include a circuit trace extending therethrough that is coupled to each of the electrically-conductive rings  1906 ,  1908 ,  1910 , and  1912 . Referring now to  FIGS. 28-30 , a first circuit trace  1922  extends through a first hole  1920  in the base ring  1900  and is coupled to the first electrically conductive ring  1906 . The first circuit trace  1922  terminates in a first proximal contact portion  1924  on the proximal side  1907  of the base ring  1900 . See  FIG. 30 . Similarly, a second circuit trace  1928  extends through a second hole  1926  in the base ring  1900  and is coupled to the second electrically-conductive ring  1908 . The second circuit trace  1928  terminates in a second proximal contact  1930  on the proximal side  1907  of the base ring  1900 . A third circuit trace  1934  extends through a third hole  1932  in the base ring and is attached to the third electrically-conductive ring  1910 . The third circuit trace  1934  terminates in a third proximal contact  1936  on the proximal side  1907  of the base ring. A fourth circuit trace  1940  extends through a fourth hole  1938  in the base ring  1900  to be attached to the fourth electrically-conductive ring  1912 . The fourth circuit trace  1940  terminates in a fourth proximal contact  1942  on the proximal side  1907  of the base ring  1900 . 
     Referring now to  FIG. 27 , the base ring  1900  is configured to be non-rotatably supported within the nozzle  1201  by a mounting flange  1950  that is non-rotatably coupled to the mounting hub portion  1241 ″ of the chassis  1240 ″. The mounting hub portion  1241 ″ may be formed with a flat surface  1243 ″ for supporting a transverse mounting member of the type, for example, described above that includes a plurality (preferably four) leads that may be coupled to, for example, a circuit board or other corresponding electrical components supported on the chassis in the various manners and arrangements described herein as well as in U.S. patent application Ser. No. 13/803,086. The transverse support member has been omitted for clarity in  FIGS. 26 and 27 . However, as can be seen in  FIGS. 26 and 27 , the mounting flange  1950  has a notch  1952  therein that is adapted to engage a portion of the flat surface  1243 ″ on the mounting hub portion  1241 ″. As can be seen in  FIG. 27 , the mounting flange  1950  may further include a flange hub portion  1954  that comprises a series of spring tabs  1956  that serve to fixedly attach the base ring  1900  to the mounting flange  1950 . It will be understood that the closure tube  1260  and spine  1210  extend through the flange hub  1954  and are rotatable relative thereto with the nozzle  1201 . 
     In the depicted embodiment for example, the electrical component  1800 ″ is mounted within the nozzle  1201  for rotation about the slip ring assembly  1610 ″ such that, for example, contact  1802 ″ in the component  1800 ″ is in constant electrical contact with rings  1906 ; contact  1804 ″ is in contact with ring  1908 ; contact  1806 ″ is in contact with ring  1910 ; and contact  1808 ″ is in contact with ring  1912  even when the nozzle  1201  is rotated relative to the chassis  1240 ″. It will be understood however, that the various advantages of the slip ring connector  1600 ″ may also be obtained in applications wherein the slip ring assembly  1610 ″ is supported for rotation about the shaft axis SA-SA and the electrical component  1800 ″ is fixedly mounted relative thereto. It will be further appreciated that the slip ring connector  1600 ″ may be effectively employed in connection with a variety of different components and applications outside the field of surgery wherein it is desirable to provide electrical connections between components that rotate relative to each other. 
     The slip ring connector  1600 ″ comprises a radial slip ring that provides a conductive contact means of passing signal(s) and power to and from any radial position and after shaft rotation. In applications wherein the electrical component comprises a battery contact, the battery contact position can be situated relative to the mounting member to minimize any tolerance stack-up between those components. The slip ring connector  1600 ″ represents a low cost and compact coupling arrangement that can be assembled with minimal manufacturing costs. The unique and novel contact arrangement facilitates complete clockwise and counterclockwise rotation about the shaft axis while remaining in electrical contact with the corresponding annular electrically-conductive rings. 
       FIGS. 31-36  generally depict a motor-driven surgical fastening and cutting instrument  2000 . As illustrated in  FIGS. 31 and 32 , the surgical instrument  2000  may include a handle assembly  2002 , a shaft assembly  2004 , and a power assembly  2006  (or “power source” or “power pack”). The shaft assembly  2004  may include an end effector  2008  which, in certain circumstances, can be configured to act as an endocutter for clamping, severing, and/or stapling tissue, although, in other instances, different types of end effectors may be used, such as end effectors for other types of surgical devices, graspers, cutters, staplers, clip appliers, access devices, drug/gene therapy devices, ultrasound devices, RF device, and/or laser devices, for example. Several RF devices may be found in U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008. The entire disclosures of U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008, are incorporated herein by reference in their entirety. 
     Referring primarily to  FIGS. 32 and 33 , the handle assembly  2002  can be employed with a plurality of interchangeable shaft assemblies such as, for example, the shaft assembly  2004 . Such interchangeable shaft assemblies may comprise surgical end effectors such as, for example, the end effector  2008  that can be configured to perform one or more surgical tasks or procedures. Examples of suitable interchangeable shaft assemblies are disclosed in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, filed Mar. 14, 2013. The entire disclosure of U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, filed Mar. 14, 2013, is hereby incorporated by reference herein in its entirety. 
     Referring primarily to  FIG. 32 , the handle assembly  2002  may comprise a housing  2010  that consists of a handle  2012  that may be configured to be grasped, manipulated and actuated by a clinician. However, it will be understood that the various unique and novel arrangements of the various forms of interchangeable shaft assemblies disclosed herein also may be effectively employed in connection with robotically-controlled surgical systems. Thus, the term “housing” also may encompass a housing or similar portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the interchangeable shaft assemblies disclosed herein and their respective equivalents. For example, the interchangeable shaft assemblies disclosed herein may be employed with various robotic systems, instruments, components and methods disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535. U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, is incorporated by reference herein in its entirety. 
     Referring again to  FIG. 32 , the handle assembly  2002  may operably support a plurality of drive systems therein that can be configured to generate and apply various control motions to corresponding portions of the interchangeable shaft assembly that is operably attached thereto. For example, the handle assembly  2002  can operably support a first or closure drive system, which may be employed to apply closing and opening motions to the shaft assembly  2004  while operably attached or coupled to the handle assembly  2002 . In at least one form, the handle assembly  2002  may operably support a firing drive system that can be configured to apply firing motions to corresponding portions of the interchangeable shaft assembly attached thereto. 
     Referring primarily to  FIGS. 33A and 33B , the handle assembly  2002  may include a motor  2014  which can be controlled by a motor driver  2015  and can be employed by the firing system of the surgical instrument  2000 . In various forms, the motor  2014  may be a DC brushed driving motor having a maximum rotation of, approximately, 25,000 RPM, for example. In other arrangements, the motor  2014  may include a brushless motor, a cordless motor, a synchronous motor, a stepper motor, or any other suitable electric motor. In certain circumstances, the motor driver  2015  may comprise an H-Bridge FETs  2019 , as illustrated in  FIGS. 33A and 33B , for example. The motor  2014  can be powered by the power assembly  2006  ( FIG. 35 ), which can be releasably mounted to the handle assembly  2002 , power assembly  2006  being configured to supply control power to the surgical instrument  2000 . The power assembly  2006  may comprise a battery  2007  ( FIG. 36 ) which may include a number of battery cells connected in series that can be used as the power source to power the surgical instrument  2000 . In such configuration, the power assembly  2006  may be referred to as a battery pack. In certain circumstances, the battery cells of the power assembly  2006  may be replaceable and/or rechargeable. In at least one example, the battery cells can be Lithium-Ion batteries which can be separably couplable to the power assembly  2006 . 
     Examples of drive systems and closure systems that are suitable for use with the surgical instrument  2000  are disclosed in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is incorporated by reference herein in its entirety. For example, the electric motor  2014  can include a rotatable shaft (not shown) that may operably interface with a gear reducer assembly that can be mounted in meshing engagement with a set, or rack, of drive teeth on a longitudinally-movable drive member. In use, a voltage polarity provided by the battery  2007  ( FIG. 36 ) can operate the electric motor  2014  to drive the longitudinally-movable drive member to effectuate the end effector  2008 . For example, the motor  2014  can be configured to drive the longitudinally-movable drive member to advance a firing mechanism to fire staples into tissue captured by the end effector  2008  from a staple cartridge assembled with the end effector  2008  and/or advance a cutting member  2011  ( FIG. 34 ) to cut tissue captured by the end effector  2008 , for example. 
     In certain circumstances, the surgical instrument  2000  may comprise a lockout mechanism to prevent a user from coupling incompatible handle assemblies and power assemblies. For example, as illustrated in  FIG. 35 , the power assembly  2006  may include a mating element  2011 . In certain circumstances, the mating element  2011  can be a tab extending from the power assembly  2006 . In certain instances, the handle assembly  2002  may comprise a corresponding mating element (not shown) for mating engagement with the mating element  2011 . Such an arrangement can be useful in preventing a user from coupling incompatible handle assemblies and power assemblies. 
     The reader will appreciate that different interchangeable shaft assemblies may possess different power requirements. The power required to advance a cutting member through an end effector and/or to fire staples may depend, for example, on the distance traveled by the cutting member, the staple cartridge being used, and/or the type of tissue being treated. That said, the power assembly  2006  can be configured to meet the power requirements of various interchangeable shaft assemblies. For example, as illustrated in  FIG. 34 , the cutting member  2011  of the shaft assembly  2004  can be configured to travel a distance D 1  along the end effector  2008 . On the other hand, another interchangeable shaft assembly  2004 ′ may include a cutting member  2011 ′ which can be configured to travel a distance D 2 , different from the distance D 1 , along an end effector  2008 ′ of the interchangeable shaft assembly  2004 ′. The power assembly  2006  can be configured to provide a first power output sufficient to power the motor  2014  to advance the cutting member  2011  the distance D 1  while the interchangeable shaft assembly  2004  is coupled to the handle assembly  2002  and can be configured to provide a second power output, different from the first power output, which is sufficient to power the motor  2014  to advance the cutting member  2011 ′ the distance D 2  while the interchangeable shaft assembly  2004 ′ is coupled to the handle assembly  2002 , for example. As illustrated in  FIGS. 33A and 33B  and as described below in greater detail, the power assembly  2006  may include a power management controller  2016  ( FIG. 36 ) which can be configured to modulate the power output of the power assembly  2006  to deliver a first power output to power the motor  2014  to advance the cutting member  2011  the distance D 1  while the interchangeable shaft assembly  2004  is coupled to the handle assembly  2002  and to deliver a second power output to power the motor  2014  to advance the cutting member  2011 ′ the distance D 2  while the interchangeable shaft assembly  2004 ′ is coupled to the handle assembly  2002 , for example. Such modulation can be beneficial in avoiding transmission of excessive power to the motor  2014  beyond the requirements of an interchangeable shaft assembly that is coupled to the handle assembly  2002 . 
     Referring again to  FIGS. 32-36 , the handle assembly  2002  can be releasably coupled or attached to an interchangeable shaft assembly such as, for example, the shaft assembly  2004 . In certain instances, the handle assembly  2002  can be releasably coupled or attached to the power assembly  2006 . Various coupling means can be utilized to releasably couple the handle assembly  2002  to the shaft assembly  2004  and/or to the power assembly  2006 . Exemplary coupling mechanisms are described in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013. For example, the shaft assembly  2004  may include a shaft attachment module  2018  ( FIG. 32 ) which may further include a latch actuator assembly that may be configured to cooperate with a lock yoke that is pivotally coupled to the shaft attachment module  2018  for selective pivotal travel relative thereto, wherein the lock yoke may include proximally protruding lock lugs that are configured for releasable engagement with corresponding lock detents or grooves formed in a hand assembly attachment module  2020  of the handle assembly  2002 . 
     Referring now primarily to  FIGS. 33A-36 , the shaft assembly  2004  may include a shaft assembly controller  2022  which can communicate with the power management controller  2016  through an interface  2024  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . For example, the interface  2024  may comprise a first interface portion  2025  which may include one or more electric connectors  2026  for coupling engagement with corresponding shaft assembly electric connectors  2028  and a second interface portion  2027  which may include one or more electric connectors  2030  for coupling engagement with corresponding power assembly electric connectors  2032  to permit electrical communication between the shaft assembly controller  2022  and the power management controller  2016  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . One or more communication signals can be transmitted through the interface  2024  to communicate one or more of the power requirements of the attached interchangeable shaft assembly  2004  to the power management controller  2016 . In response, the power management controller may modulate the power output of the battery  2007  of the power assembly  2006 , as described below in greater detail, in accordance with the power requirements of the attached shaft assembly  2004 . In certain circumstances, one or more of the electric connectors  2026 ,  2028 ,  2030 , and/or  2032  may comprise switches which can be activated after mechanical coupling engagement of the handle assembly  2002  to the shaft assembly  2004  and/or to the power assembly  2006  to allow electrical communication between the shaft assembly controller  2022  and the power management controller  2016 . 
     In certain circumstances, the interface  2024  can facilitate transmission of the one or more communication signals between the power management controller  2016  and the shaft assembly controller  2022  by routing such communication signals through a main controller  2017  ( FIGS. 33A and 33B ) residing in the handle assembly  2002 , for example. In other circumstances, the interface  2024  can facilitate a direct line of communication between the power management controller  2016  and the shaft assembly controller  2022  through the handle assembly  2002  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . 
     In one instance, the main microcontroller  2017  may be any single core or multicore processor such as those known under the trade name ARM Cortex by Texas Instruments. In one instance, the surgical instrument  2000  may comprise a power management controller  2016  such as, for example, a safety microcontroller platform comprising two microcontroller-based families such as TMS570 and RM4x known under the trade name Hercules ARM Cortex R4, also by Texas Instruments. Nevertheless, other suitable substitutes for microcontrollers and safety processor may be employed, without limitation. In one instance, the safety processor  1004  may be configured specifically for IEC 61508 and ISO 26262 safety critical applications, among others, to provide advanced integrated safety features while delivering scalable performance, connectivity, and memory options. 
     In certain instances, the microcontroller  2017  may be an LM 4F230H5QR, available from Texas Instruments, for example. In at least one example, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available for the product datasheet. The present disclosure should not be limited in this context. 
     Referring now primarily to  FIGS. 36 and 37 , the power assembly  2006  may include a power management circuit  2034  which may comprise the power management controller  2016 , a power modulator  2038 , and a current sense circuit  2036 . The power management circuit  2034  can be configured to modulate power output of the battery  2007  based on the power requirements of the shaft assembly  2004  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . For example, the power management controller  2016  can be programmed to control the power modulator  2038  of the power output of the power assembly  2006  and the current sense circuit  2036  can be employed to monitor power output of the power assembly  2006  to provide feedback to the power management controller  2016  about the power output of the battery  2007  so that the power management controller  2016  may adjust the power output of the power assembly  2006  to maintain a desired output, as illustrated in  FIG. 37 . 
     It is noteworthy that the power management controller  2016  and/or the shaft assembly controller  2022  each may comprise one or more processors and/or memory units which may store a number of software modules. Although certain modules and/or blocks of the surgical instrument  2000  may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used. Further, although various instances may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, Digital Signal Processors (DSPs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components. 
     In certain instances, the surgical instrument  2000  may comprise an output device  2042  which may include one or more devices for providing a sensory feedback to a user. Such devices may comprise, for example, visual feedback devices (e.g., an LCD display screen, LED indicators), audio feedback devices (e.g., a speaker, a buzzer) or tactile feedback devices (e.g., haptic actuators). In certain circumstances, the output device  2042  may comprise a display  2043  which may be included in the handle assembly  2002 , as illustrated in  FIG. 36 . The shaft assembly controller  2022  and/or the power management controller  2016  can provide feedback to a user of the surgical instrument  2000  through the output device  2042 . The interface  2024  can be configured to connect the shaft assembly controller  2022  and/or the power management controller  2016  to the output device  2042 . The reader will appreciate that the output device  2042  can instead be integrated with the power assembly  2006 . In such circumstances, communication between the output device  2042  and the shaft assembly controller  2022  may be accomplished through the interface  2024  while the shaft assembly  2004  is coupled to the handle assembly  2002 . 
     Referring to  FIGS. 38 and 39 , a surgical instrument  2050  is illustrated. The surgical instrument  2050  is similar in many respects to the surgical fastening and cutting instrument  2000  ( FIG. 31 ). For example, the surgical instrument  2050  may include an end effector  2052  which is similar in many respects to the end effector  2008 . For example, the end effector  2052  can be configured to act as an endocutter for clamping, severing, and/or stapling tissue. 
     Further to the above, the surgical instrument  2050  may include an interchangeable working assembly  2054  which may include a handle assembly  2053  and a shaft  2055  extending between the handle assembly  2053  and the end effector  2052 , as illustrated in  FIG. 38 . In certain instances, the surgical instrument  2050  may include a power assembly  2056  which can be employed with a plurality of interchangeable working assemblies such as, for example, the interchangeable working assembly  2054 . Such interchangeable working assemblies may include surgical end effectors such as, for example, the end effector  2052  that can be configured to perform one or more surgical tasks or procedures. In certain circumstances, the handle assembly  2053  and the shaft  2055  may be integrated into a single unit. In other circumstances, the handle assembly  2053  and the shaft  2055  may be separably couplable to each other. 
     Similar to the surgical instrument  2000 , the surgical instrument  2050  may operably support a plurality of drive systems which can be powered by the power assembly  2056  while the power assembly  2056  is coupled to the interchangeable working assembly  2054 . For example, the interchangeable working assembly  2054  can operably support a closure drive system, which may be employed to apply closing and opening motions to the end effector  2052 . In at least one form, the interchangeable working assembly  2054  may operably support a firing drive system that can be configured to apply firing motions to the end effector  2052 . Examples of drive systems suitable for use with the surgical instrument  2050  are described in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is incorporated by reference herein in its entirety. 
     Referring to  FIG. 39 , the power assembly  2056  of the surgical instrument  2050  can be separably coupled to an interchangeable working assembly such as, for example, the interchangeable working assembly  2054 . Various coupling means can be utilized to releasably couple the power assembly  2056  to the interchangeable working assembly  2054 . Exemplary coupling mechanisms are described herein and are described in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is incorporated by reference herein in its entirety. 
     Still referring to  FIG. 39 , the power assembly  2056  may include a power source  2058  such as, for example, a battery which can be configured to power the interchangeable working assembly  2054  while coupled to the power assembly  2056 . In certain instances, the power assembly  2056  may include a memory  2060  which can be configured to receive and store information about the battery  2058  and/or the interchangeable working assembly  2054  such as, for example, the state of charge of the battery  2058 , the number of treatment cycles performed using the battery  2058 , and/or identification information for the interchangeable working assemblies coupled to the power assembly  2056  during the life cycle of the battery  2058 . Further to the above, the interchangeable working assembly  2054  may include a controller  2062  which can be configured to provide the memory  2060  with such information about the battery  2058  and/or the interchangeable working assembly  2054 . 
     Still referring to  FIG. 39 , the power assembly  2056  may include an interface  2064  which can be configured to facilitate electrical communication between the memory  2060  of the power assembly  2056  and a controller of an interchangeable working assembly that is coupled to the power assembly  2056  such as, for example, the controller  2062  of the interchangeable working assembly  2054 . For example, the interface  2064  may comprise one or more connectors  2066  for coupling engagement with corresponding working assembly connectors  2068  to permit electrical communication between the controller  2062  and the memory  2060  while the interchangeable working assembly  2054  is coupled to the power assembly  2056 . In certain circumstances, one or more of the electric connectors  2066  and/or  2068  may comprise switches which can be activated after coupling engagement of the interchangeable working assembly  2054  and the power assembly  2056  to allow electric communication between the controller  2062  and the memory  2060 . 
     Still referring to  FIG. 39 , the power assembly  2056  may include a state of charge monitoring circuit  2070 . In certain circumstances, the state of charge monitoring circuit  2070  may comprise a coulomb counter. The controller  2062  can be in communication with the state of charge monitoring circuit  2070  while the interchangeable working assembly  2054  is coupled to the power assembly  2056 . The state of charge monitoring circuit  2070  can be operable to provide for accurate monitoring of charge states of the battery  2058 . 
       FIG. 40  depicts an exemplary module  2072  for use with a controller of an interchangeable working assembly such as, for example, the controller  2062  of the interchangeable working assembly  2054  while coupled to the power assembly  2056 . For example, the controller  2062  may comprise one or more processors and/or memory units which may store a number of software modules such as, for example, the module  2072 . Although certain modules and/or blocks of the surgical instrument  2050  may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used. Further, although various instances may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, DSPs, PLDs, ASICs, circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components. 
     In any event, upon coupling the interchangeable working assembly  2054  to the power assembly  2056 , the interface  2064  may facilitate communication between the controller  2062  and the memory  2060  and/or the state of charge monitoring circuit  2070  to execute the module  2072 , as illustrated in  FIG. 40 . For example, the controller  2062  of the interchangeable working assembly  2054  may utilize the state of charge monitoring circuit  2070  to measure the state of charge of the battery  2058 . The controller  2062  may then access the memory  2060  and determine whether a previous value for the state of charge of the battery  2058  is stored in the memory  2060 . When a previous value is detected, the controller  2060  may compare the measured value to the previously stored value. When the measured value is different from the previously stored value, the controller  2060  may update the previously stored value. When no value is previously recorded, the controller  2060  may store the measured value into the memory  2060 . In certain circumstances, the controller  2060  may provide visual feedback to a user of the surgical instrument  2050  as to the measured state of charge of the battery  2058 . For example, the controller  2060  may display the measured value of the state of charge of the battery  2058  on an LCD display screen which, in some circumstances, can be integrated with the interchangeable working assembly  2054 . 
     Further to the above, the module  2072  also can be executed by other controllers upon coupling the interchangeable working assemblies of such other controllers to the power assembly  2056 . For example, a user may disconnect the interchangeable working assembly  2054  from the power assembly  2056 . The user may then connect another interchangeable working assembly comprising another controller to the power assembly  2056 . Such controller may in turn utilize the coulomb counting circuit  2070  to measure the state of charge of the battery  2058  and may then access the memory  2060  and determine whether a previous value for the state of charge of the battery  2058  is stored in the memory  2060  such as, for example, a value entered by the controller  2060  while the interchangeable working assembly  2054  was coupled to the power assembly  2056 . When a previous value is detected, the controller may compare the measured value to the previously stored value. When the measured value is different from the previously stored value, the controller may update the previously stored value. 
       FIG. 41  depicts a surgical instrument  2090  which is similar in many respects to the surgical instrument  2000  ( FIG. 31 ) and/or the surgical instrument  2050  ( FIG. 38 ). For example, the surgical instrument  2090  may include an end effector  2092  which is similar in many respects to the end effector  2008  and/or the end effector  2052 . For example, the end effector  2092  can be configured to act as an endocutter for clamping, severing, and/or stapling tissue. 
     Further to the above, the surgical instrument  2090  may include an interchangeable working assembly  2094  which may include a handle assembly  2093  and a shaft  2095  which may extend between the handle assembly  2093  and the end effector  2092 . In certain instances, the surgical instrument  2090  may include a power assembly  2096  which can be employed with a plurality of interchangeable working assemblies such as, for example, the interchangeable working assembly  2094 . Such interchangeable working assemblies may comprise surgical end effectors such as, for example, the end effector  2092  that can be configured to perform one or more surgical tasks or procedures. In certain circumstances, the handle assembly  2093  and the shaft  2095  may be integrated into a single unit. In other circumstances, the handle assembly  2093  and the shaft  2095  can be separably couplable to each other. 
     Furthermore, the power assembly  2096  of the surgical instrument  2090  can be separably couplable to an interchangeable working assembly such as, for example, the interchangeable working assembly  2094 . Various coupling means can be utilized to releasably couple the power assembly  2096  to the interchangeable working assembly  2094 . Similar to the surgical instrument  2050  and/or the surgical instrument  2000 , the surgical instrument  2090  may operably support one or more drive systems which can be powered by the power assembly  2096  while the power assembly  2096  is coupled to the interchangeable working assembly  2094 . For example, the interchangeable working assembly  2094  may operably support a closure drive system, which may be employed to apply closing and/or opening motions to the end effector  2092 . In at least one form, the interchangeable working assembly  2094  may operably support a firing drive system that can be configured to apply firing motions to the end effector  2092 . Exemplary drive systems and coupling mechanisms for use with the surgical instrument  2090  are described in greater detail U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is incorporated by reference herein in its entirety. 
     Referring to  FIGS. 41-45 , the interchangeable working assembly  2094  may include a motor such as, for example, the motor  2014  ( FIG. 44 ) and a motor driver such as, for example, the motor driver  2015  ( FIG. 44 ) which can be employed to motivate the closure drive system and/or the firing drive system of the interchangeable working assembly  2094 , for example. The motor  2014  can be powered by a battery  2098  ( FIG. 42 ) which may reside in the power assembly  2096 . As illustrated in  FIGS. 42 and 43 , the battery  2098  may include a number of battery cells connected in series that can be used as a power source to power the motor  2014 . In certain instances, the battery cells of the power assembly  2096  may be replaceable and/or rechargeable. The battery cells can be Lithium-Ion batteries which can be separably couplable to the power assembly  2096 , for example. In use, a voltage polarity provided by the power assembly  2096  can operate the motor  2014  to drive a longitudinally-movable drive member to effectuate the end effector  2092 . For example, the motor  2014  can be configured to drive the longitudinally-movable drive member to advance a cutting member to cut tissue captured by the end effector  2092  and/or a firing mechanism to fire staples from a staple cartridge assembled with the end effector  2092 , for example. The staples can be fired into tissue captured by the end effector  2092 , for example. 
     Referring now to  FIGS. 41-45 , the interchangeable working assembly  2094  may include a working assembly controller  2102  ( FIGS. 44 and 45 ) and the power assembly  2096  may include a power assembly controller  2100  ( FIGS. 42 and 43 ). The working assembly controller  2102  can be configured to generate one or more signals to communicate with the power assembly controller  2100 . In certain instances, the working assembly controller  2102  may generate the one or more signals to communicate with the power assembly controller  2100  by modulating power transmission from the power assembly  2096  to the interchangeable working assembly  2094  while the power assembly  2096  is coupled to the interchangeable working assembly  2094 . 
     Furthermore, the power assembly controller  2100  can be configured to perform one or more functions in response to receiving the one or more signals generated by the working assembly controller  2102 . For example, the interchangeable working assembly  2094  may comprise a power requirement and the working assembly controller  2102  may be configured to generate a signal to instruct the power assembly controller  2100  to select a power output of the battery  2098  in accordance with the power requirement of the interchangeable working assembly  2094 ; the signal can be generated, as described above, by modulating power transmission from the power assembly  2096  to the interchangeable working assembly  2094  while the power assembly  2096  is coupled to the interchangeable working assembly  2094 . In response to receiving the signal, the power assembly controller  2100  may set the power output of the battery  2098  to accommodate the power requirement of the interchangeable working assembly  2094 . The reader will appreciate that various interchangeable working assemblies may be utilized with the power assembly  2096 . The various interchangeable working assemblies may comprise various power requirements and may generate signals unique to their power requirements during their coupling engagement with the power assembly  2096  to alert the power assembly controller  2100  to set the power output of the battery  2098  in accordance with their power requirements. 
     Referring now primarily to  FIGS. 42 and 43 , the power assembly  2096  may include a power modulator control  2106  which may comprise, for example, one or more field-effect transistors (FETs), a Darlington array, an adjustable amplifier, and/or any other power modulator. The power assembly controller  2100  may actuate the power modulator control  2106  to set the power output of the battery  2098  to the power requirement of the interchangeable working assembly  2094  in response to the signal generated by working assembly controller  2102  while the interchangeable working assembly  2094  is coupled to the power assembly  2096 . 
     Still referring primarily to  FIGS. 42 and 43 , the power assembly controller  2100  can be configured to monitor power transmission from the power assembly  2096  to the interchangeable working assembly  2094  for the one or more signals generated by the working assembly controller  2102  of the interchangeable working assembly  2094  while the interchangeable working assembly  2094  is coupled to the power assembly  2096 . As illustrated in  FIG. 42 , the power assembly controller  2100  may utilize a voltage monitoring mechanism for monitoring the voltage across the battery  2098  to detect the one or more signals generated by the working assembly controller  2102 , for example. In certain instances, a voltage conditioner can be utilized to scale the voltage of the battery  2098  to be readable by an Analog to Digital Converter (ADC) of the power assembly controller  2100 . As illustrated in  FIG. 42 , the voltage conditioner may comprise a voltage divider  2108  which can create a reference voltage or a low voltage signal proportional to the voltage of the battery  2098  which can be measured and reported to the power assembly controller  2100  through the ADC, for example. 
     In other circumstances, as illustrated in  FIG. 43 , the power assembly  2096  may comprise a current monitoring mechanism for monitoring current transmitted to the interchangeable working assembly  2094  to detect the one or more signals generated by the working assembly controller  2102 , for example. In certain instances, the power assembly  2096  may comprise a current sensor  2110  which can be utilized to monitor current transmitted to the interchangeable working assembly  2094 . The monitored current can be reported to the power assembly controller  2100  through an ADC, for example. In other circumstances, the power assembly controller  2100  may be configured to simultaneously monitor both of the current transmitted to the interchangeable working assembly  2094  and the corresponding voltage across the battery  2098  to detect the one or more signals generated by the working assembly controller  2102 . The reader will appreciate that various other mechanisms for monitoring current and/or voltage can be utilized by the power assembly controller  2100  to detect the one or more signals generated by the working assembly controller  2102 ; all such mechanisms are contemplated by the present disclosure. 
     As illustrated in  FIG. 44 , the working assembly controller  2102  can be configured to generate the one or more signals for communication with the power assembly controller  2100  by effectuating the motor driver  2015  to modulate the power transmitted to the motor  2014  from the battery  2098 . In result, the voltage across the battery  2098  and/or the current drawn from the battery  2098  to power the motor  2014  may form discrete patterns or waveforms that represent the one or more signals. As described above, the power assembly controller  2100  can be configured to monitor the voltage across the battery  2098  and/or the current drawn from the battery  2098  for the one or more signals generated by the working assembly controller  2102 . 
     Upon detecting a signal, the power assembly controller  2100  can be configured to perform one or more functions that correspond to the detected signal. In at least one example, upon detecting a first signal, the power assembly controller  2100  can be configured to actuate the power modulator control  2106  to set the power output of the battery  2098  to a first duty cycle. In at least one example, upon detecting a second signal, the power assembly controller  2100  can be configured to actuate the power modulator control  2106  to set the power output of the battery  2098  to a second duty cycle different from the first duty cycle. 
     In certain circumstances, as illustrated in  FIG. 45 , the interchangeable working assembly  2094  may include a power modulation circuit  2012  which may comprise one or more field-effect transistors (FETs) which can be controlled by the working assembly controller  2102  to generate a signal or a waveform recognizable by the power assembly controller  2100 . For example, in certain circumstances, the working assembly controller  2102  may operate the power modulation circuit  2012  to amplify the voltage higher than the voltage of the battery  2098  to trigger a new power mode of the power assembly  2096 , for example. 
     Referring now primarily to  FIGS. 42 and 43 , the power assembly  2096  may comprise a switch  2104  which can be switchable between an open position and a closed position. The switch  2104  can be transitioned from the open position to the closed positioned when the power assembly  2096  is coupled with the interchangeable working assembly  2094 , for example. In certain instances, the switch  2104  can be manually transitioned from the open position to the closed position after the power assembly  2096  is coupled with the interchangeable working assembly  2094 , for example. While the switch  2104  is in the open position, components of the power assembly  2096  may draw sufficiently low or no power to retain capacity of the battery  2098  for clinical use. The switch  2104  can be a mechanical, reed, hall, or any other suitable switching mechanism. Furthermore, in certain circumstances, the power assembly  2096  may include an optional power supply  2105  which may be configured to provide sufficient power to various components of the power assembly  2096  during use of the battery  2098 . Similarly, the interchangeable working assembly  2094  also may include an optional power supply  2107  which can be configured to provide sufficient power to various components of the interchangeable working assembly  2094 . 
     In use, as illustrated in  FIG. 46 , the power assembly  2096  can be coupled to the interchangeable working assembly  2094 . In certain instances, as described above, the switch  2104  can be transitioned to the closed configuration to electrically connect the interchangeable working assembly  2094  to the power assembly  2096 . In response, the interchangeable working assembly  2094  may power up and may, at least initially, draw relatively low current from the battery  2098 . For example, the interchangeable working assembly  2094  may draw less than or equal to 1 ampere to power various components of the interchangeable working assembly  2094 . In certain instances, the power assembly  2096  also may power up as the switch  2014  is transitioned to the closed position. In response, the power assembly controller  2100  may begin to monitor current draw from the interchangeable working assembly  2094 , as described in greater detail above, by monitoring voltage across the battery  2098  and/or current transmission from the battery  2098  to the interchangeable working assembly  2094 , for example. 
     To generate and transmit a communication signal to the power assembly controller  2100  via power modulation, the working assembly controller  2102  may employ the motor drive  2015  to pulse power to the motor  2014  in patterns or waveforms of power spikes, for example. In certain circumstances, the working assembly controller  2102  can be configured to communicate with the motor driver  2015  to rapidly switch the direction of motion of the motor  2014  by rapidly switching the voltage polarity across the windings of the motor  2014  to limit the effective current transmission to the motor  2014  resulting from the power spikes. In result, as illustrated in  FIG. 47C , the effective motor displacement resulting from the power spikes can be reduced to minimize effective displacement of a drive system of the surgical instrument  2090  that is coupled to the motor  2014  in response to the power spikes. 
     Further to the above, the working assembly controller  2102  may communicate with the power assembly controller  2100  by employing the motor driver  2015  to draw power from the battery  2098  in spikes arranged in predetermined packets or groups which can be repeated over predetermined time periods to form patterns detectable by the power assembly controller  2100 . For example, as illustrated in  FIGS. 47A and 47B , the power assembly controller  2100  can be configured to monitor voltage across the battery  2100  for predetermined voltage patterns such as, for example, the voltage pattern  2103  ( FIG. 47A ) and/or predetermined current patterns such as, for example, the current pattern  2109  ( FIG. 47B ) using voltage and/or current monitoring mechanisms as described in greater detail above. Furthermore, the power assembly controller  2100  can be configured to perform one or more functions upon detecting of a pattern. The reader will appreciate that the communication between the power assembly controller  2100  and the working assembly controller  2102  via power transmission modulation may reduce the number of connection lines needed between the interchangeable working assembly  2094  and the power assembly  2096 . 
     In certain circumstances, the power assembly  2096  can be employed with various interchangeable working assemblies of multiple generations which may comprise different power requirements. Some of the various interchangeable workings assemblies may comprise communication systems, as described above, while others may lack such communication systems. For example, the power assembly  2096  can be utilized with a first generation interchangeable working assembly which lacks the communication system described above. Alternatively, the power assembly  2096  can be utilized with a second generation interchangeable working assembly such as, for example, the interchangeable working assembly  2094  which comprises a communication system, as described above. 
     Further to the above, the first generation interchangeable working assembly may comprise a first power requirement and the second generation interchangeable working assembly may comprise a second power requirement which can be different from the first power requirement. For example, the first power requirement may be less than the second power requirement. To accommodate the first power requirement of the first generation interchangeable working assembly and the second power requirement of the second generation interchangeable working assembly, the power assembly  2096  may comprise a first power mode for use with the first generation interchangeable working assembly and a second power mode for use with the second generation interchangeable working assembly. In certain instances, the power assembly  2096  can be configured to operate at a default first power mode corresponding to the power requirement of the first generation interchangeable working assembly. As such, when a first generation interchangeable working assembly is connected to the power assembly  2096 , the default first power mode of the power assembly  2096  may accommodate the first power requirement of the first generation interchangeable working assembly. However, when a second generation interchangeable working assembly such as, for example, the interchangeable working assembly  2094  is connected to the power assembly  2096 , the working assembly controller  2102  of the interchangeable working assembly  2094  may communicate, as described above, with the power assembly controller  2100  of the power assembly  2096  to switch the power assembly  2096  to the second power mode to accommodate the second power requirement of the interchangeable working assembly  2094 . The reader will appreciate that since the first generation interchangeable working assembly lacks the ability to generate a communication signal, the power assembly  2096  will remain in the default first power mode while connected to the first generation interchangeable working assembly. 
     As described above, the battery  2098  can be rechargeable. In certain circumstances, it may be desirable to drain the battery  2098  prior to shipping the power assembly  2096 . A dedicated drainage circuit can be activated to drain the battery  2098  in preparation for shipping of the power assembly  2096 . Upon reaching its final destination, the battery  2098  can be recharged for use during a surgical procedure. However, the drainage circuit may continue to consume energy from the battery  2098  during clinical use. In certain circumstances, the interchangeable working assembly controller  2102  can be configured to transmit a drainage circuit deactivation signal to the power assembly controller  2100  by modulating power transmission from the battery  2098  to the motor  2014 , as described in greater detail above. The power assembly controller  2100  can be programmed to deactivate the drainage circuit to prevent drainage of the battery  2098  by the drainage circuit in response to the drainage circuit deactivation signal, for example. The reader will appreciate that various communication signals can be generated by the working assembly controller  2102  to instruct the power assembly controller  2100  to perform various functions while the power assembly  2096  is coupled to the interchangeable working assembly  2094 . 
     Referring again to  FIGS. 42-45 , the power assembly controller  2100  and/or the working assembly controller  2102  may comprise one or more processors and/or memory units which may store a number of software modules. Although certain modules and/or blocks of the surgical instrument  2050  may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used. Further, although various instances may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, DSPs, PLDs, ASICs, circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components. 
       FIG. 48  generally depicts a motor-driven surgical instrument  2200 . In certain circumstances, the surgical instrument  2200  may include a handle assembly  2202 , a shaft assembly  2204 , and a power assembly  2206  (or “power source” or “power pack”). The shaft assembly  2204  may include an end effector  2208  which, in certain circumstances, can be configured to act as an endocutter for clamping, severing, and/or stapling tissue, although, in other circumstances, different types of end effectors may be used, such as end effectors for other types of surgical devices, graspers, cutters, staplers, clip appliers, access devices, drug/gene therapy devices, ultrasound, RF and/or laser devices, etc. Several RF devices may be found in U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008, the entire disclosures of which are incorporated herein by reference in their entirety. 
     In certain circumstances, the handle assembly  2202  can be separably couplable to the shaft assembly  2204 , for example. In such circumstances, the handle assembly  2202  can be employed with a plurality of interchangeable shaft assemblies which may comprise surgical end effectors such as, for example, the end effector  2208  that can be configured to perform one or more surgical tasks or procedures. For example, one or more of the interchangeable shaft assemblies may employ end effectors that are adapted to support different sizes and types of staple cartridges, have different shaft lengths, sizes, and types, etc. Examples of suitable interchangeable shaft assemblies are disclosed in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is hereby incorporated by reference herein in its entirety. 
     Referring still to  FIG. 48 , the handle assembly  2202  may comprise a housing  2210  that consists of a handle  2212  that may be configured to be grasped, manipulated, and/or actuated by a clinician. However, it will be understood that the various unique and novel arrangements of the housing  2210  also may be effectively employed in connection with robotically-controlled surgical systems. Thus, the term “housing” also may encompass a housing or similar portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the shaft assembly  2204  disclosed herein and its respective equivalents. For example, the housing  2210  disclosed herein may be employed with various robotic systems, instruments, components and methods disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, which is incorporated by reference herein in its entirety. 
     In at least one form, the surgical instrument  2200  may be a surgical fastening and cutting instrument. Furthermore, the housing  2210  may operably support one or more drive systems. For example, as illustrated in  FIG. 50 , the housing  2210  may support a drive system referred to herein as firing drive system  2214  that is configured to apply firing motions to the end effector  2208 . The firing drive system  2214  may employ an electric motor  2216 , which can be located in the handle  2212 , for example. In various forms, the motor  2216  may be a DC brushed driving motor having a maximum rotation of, approximately, 25,000 RPM, for example. In other arrangements, the motor may include a brushless motor, a cordless motor, a synchronous motor, a stepper motor, or any other suitable electric motor. A battery  2218  (or “power source” or “power pack”), such as a Li ion battery, for example, may be coupled to the handle  2212  to supply power to a control circuit board assembly  2220  and ultimately to the motor  2216 . 
     In certain circumstances, referring still to  FIG. 50 , the electric motor  2216  can include a rotatable shaft (not shown) that may operably interface with a gear reducer assembly  2222  that may be mounted in meshing engagement with a with a set, or rack, of drive teeth  2224  on a longitudinally-movable drive member  2226 . In use, a voltage polarity provided by the battery  2218  can operate the electric motor  2216  in a clockwise direction wherein the voltage polarity applied to the electric motor by the battery  2218  can be reversed in order to operate the electric motor  2216  in a counter-clockwise direction. When the electric motor  2216  is rotated in one direction, the drive member  2226  will be axially driven in a distal direction “D”, for example, and when the motor  2216  is driven in the opposite rotary direction, the drive member  2226  will be axially driven in a proximal direction “P”, for example, as illustrated in  FIG. 50 . The handle  2212  can include a switch which can be configured to reverse the polarity applied to the electric motor  2216  by the battery  2218 . As with the other forms described herein, the handle  2212  also can include a sensor that is configured to detect the position of the drive member  2226  and/or the direction in which the drive member  2226  is being moved. 
     As indicated above, in at least one form, the longitudinally movable drive member  2226  may include a rack of drive teeth  2224  formed thereon for meshing engagement with the gear reducer assembly  2222 . In certain circumstances, as illustrated in  FIG. 50 , the surgical instrument  2200  may include a manually-actuatable “bailout” assembly  2228  that can be configured to enable a clinician to manually retract the longitudinally movable drive member  2226  when a bailout error is detected such as, for example, when the motor  2216  malfunctions during operation of the surgical instrument  2200  which may cause tissue captured by the end effector  2208  to be trapped. 
     Further to the above, as illustrated in  FIG. 50 , the bailout assembly  2228  may include a lever or bailout handle  2230  configured to be manually moved or pivoted into ratcheting engagement with the teeth  2224  in the drive member  2226 . In such circumstances, the clinician can manually retract the drive member  2226  by using the bailout handle  2230  to ratchet the drive member  2226  in the proximal direction “P”, for example, to release the trapped tissue from the end effector  2208 , for example. Exemplary bailout arrangements and other components, arrangements and systems that may be employed with the various instruments disclosed herein are disclosed in U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICAL CUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM, now U.S. Pat. No. 8,608,045, which is hereby incorporated by reference herein in its entirety. 
     Further to the above, referring now primarily to  FIGS. 48 and 50 , the bailout handle  2230  of the bailout assembly  2228  may reside within the housing  2210  of the handle assembly  2202 . In certain circumstances, access to the bailout handle  2230  can be controlled by a bailout door  2232 . The bailout door  2232  can be releasably locked to the housing  2210  to control access to the bailout handle  2230 . As illustrated in  FIG. 48 , the bailout door  2232  may include a locking mechanism such as, for example, a snap-type locking mechanism  2234  for locking engagement with the housing  2210 . Other locking mechanisms for locking the bailout door  2232  to the housing  2210  are contemplated by the present disclosure. In use, a clinician may obtain access to the bailout handle  2230  by unlocking the locking mechanism  2234  and opening the bailout door  2232 . In at least one example, the bailout door  2232  can be separably coupled to the housing  2232  and can be detached from the housing  2210  to provide access to the bailout handle  2230 , for example. In another example, the bailout door  2232  can be pivotally coupled to the housing  2210  via hinges (not shown) and can be pivoted relative to the housing  2210  to provide access to the bailout handle  2230 , for example. In yet another example, the bailout door  2232  can be a sliding door which can be slidably movable relative to the housing  2210  to provide access to the bailout handle  2230 . 
     Referring now to  FIG. 51 , the surgical instrument  2200  may include a bailout feedback system  2236  which can be configured to guide and/or provide feedback to a clinician through the various steps of utilizing the bailout assembly  2228 , as described below in greater detail. In certain instances, the bailout feedback system  2236  may include a microcontroller  2238  and/or one or more bailout feedback elements. The electrical and electronic circuit elements associated with the bailout feedback system  2236  and/or the bailout feedback elements may be supported by the control circuit board assembly  2220 , for example. The microcontroller  2238  may generally comprise a memory  2240  and a microprocessor  2242  (“processor”) operationally coupled to the memory  2240 . The processor  2242  may control a motor driver  2244  circuit generally utilized to control the position and velocity of the motor  2216 . In certain instances, the processor  2242  can signal the motor driver  2244  to stop and/or disable the motor  2216 , as described in greater detail below. In certain instances, the processor  2242  may control a separate motor override circuit which may comprise a motor override switch that can stop and/or disable the motor  2216  during operation of the surgical instrument  2200  in response to an override signal from the processor  2242 . It should be understood that the term processor as used herein includes any suitable microprocessor, microcontroller, or other basic computing device that incorporates the functions of a computer&#39;s central processing unit (CPU) on an integrated circuit or at most a few integrated circuits. The processor is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Processors operate on numbers and symbols represented in the binary numeral system. 
     In one instance, the processor  2242  may be any single core or multicore processor such as those known under the trade name ARM Cortex by Texas Instruments. In one instance, the surgical instrument  2200  may comprise a safety processor such as, for example, a safety microcontroller platform comprising two microcontroller-based families such as TMS570 and RM4x known under the trade name Hercules ARM Cortex R4, also by Texas Instruments. Nevertheless, other suitable substitutes for microcontrollers and safety processor may be employed, without limitation. In one instance, the safety processor  1004  may be configured specifically for IEC 61508 and ISO 26262 safety critical applications, among others, to provide advanced integrated safety features while delivering scalable performance, connectivity, and memory options. 
     In certain instances, the microcontroller  2238  may be an LM 4F230H5QR, available from Texas Instruments, for example. In at least one example, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory  2240  of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available for the product datasheet. Other microcontrollers may be readily substituted for use in the bailout feedback system  2236 . Accordingly, the present disclosure should not be limited in this context. 
     Referring again to  FIG. 51 , the bailout feedback system  2236  may include a bailout door feedback element  2246 , for example. In certain instances, the bailout door feedback element  2246  can be configured to alert the processor  2242  that the locking mechanism  2234  is unlocked. In at least one example, the bailout door feedback element  2246  may comprise a switch circuit (not shown) operably coupled to the processor  2242 ; the switch circuit can be configured to be transitioned to an open configuration when the locking mechanism  2234  is unlocked by a clinician and/or transitioned to a closed configuration when the locking mechanism  2234  is locked by the clinician, for example. In at least one example, the bailout door feedback element  2246  may comprise at least one sensor (not shown) operably coupled to the processor  2242 ; the sensor can be configured to be triggered when the locking mechanism  2234  is transitioned to unlocked and/or locked configurations by the clinician, for example. The reader will appreciate that the bailout door feedback element  2246  may include other means for detecting the locking and/or unlocking of the locking mechanism  2234  by the clinician. 
     In certain instances, the bailout door feedback element  2246  may comprise a switch circuit (not shown) operably coupled to the processor  2242 ; the switch circuit can be configured to be transitioned to an open configuration when the bailout door  2232  is removed or opened, for example, and/or transitioned to a closed configuration when the bailout door  2232  is installed or closed, for example. In at least one example, the bailout door feedback element  2246  may comprise at least one sensor (not shown) operably coupled to the processor  2242 ; the sensor can be configured to be triggered when the bailout door  2232  is removed or opened, for example, and/or when the bailout door  2232  is closed or installed, for example. The reader will appreciate that the bailout door feedback element  2246  may include other means for detecting the locking and/or unlocking of the locking mechanism  2234  and/or the opening and/or closing of the bailout door  2232  by the clinician. 
     In certain instances, as illustrated in  FIG. 51 , the bailout feedback system  2236  may comprise one or more additional feedback elements  2248  which may comprise additional switch circuits and/or sensors in operable communication with the processor  2242 ; the additional switch circuits and/or sensors may be employed by the processor  2242  to measure other parameters associated with the bailout feedback system  2236 . In certain instances, the bailout feedback system  2236  may comprise one or more interfaces which may include one or more devices for providing a sensory feedback to a user. Such devices may comprise, for example, visual feedback devices such as display screens and/or LED indicators, for example. In certain instances, such devices may comprise audio feedback devices such as speakers and/or buzzers, for example. In certain instances, such devices may comprise tactile feedback devices such as haptic actuators, for example. In certain instances, such devices may comprise combinations of visual feedback devices, audio feedback devices, and/or tactile feedback devices. In certain circumstances, as illustrated in  FIG. 48 , the one or more interfaces may comprise a display  2250  which may be included in the handle assembly  2202 , for example. In certain instances, the processor  2242  may employ the display  2250  to alert, guide, and/or provide feedback to a user of the surgical instrument  2200  with regard to performing a manual bailout of the surgical instrument  2200  using the bailout assembly  2228 . 
     In certain instances, the bailout feedback system  2236  may comprise one or more embedded applications implemented as firmware, software, hardware, or any combination thereof. In certain instances, the bailout feedback system  2236  may comprise various executable modules such as software, programs, data, drivers, and/or application program interfaces (APIs), for example.  FIG. 52  depicts an exemplary module  2252  that can be stored in the memory  2240 , for example. The module  2252  can be executed by the processor  2242 , for example, to alert, guide, and/or provide feedback to a user of the surgical instrument  2200  with regard to performing a manual bailout of the surgical instrument  2200  using the bailout assembly  2228 . 
     As illustrated in  FIG. 52 , the module  2252  may be executed by the processor  2242  to provide the user with instructions as to how to access and/or use the bailout assembly  2228  to perform the manual bailout of the surgical instrument  2200 , for example. In various instances, the module  2252  may comprise one or more decision-making steps such as, for example, a decision-making step  2254  with regard to the detection of one or more errors requiring the manual bailout of the surgical instrument  2200 . 
     In various instances, the processor  2242  may be configured to detect a bailout error in response to the occurrence of one or more intervening events during the normal operation of the surgical instrument  2200 , for example. In certain instances, the processor  2242  may be configured to detect a bailout error when one or more bailout error signals are received by the processor  2242 ; the bailout error signals can be communicated to the processor  2242  by other processors and/or sensors of the surgical instrument  2200 , for example. In certain instances, a bailout error can be detected by the processor  2242  when a temperature of the surgical instrument  2200 , as detected by a sensor (not shown), exceeds a threshold, for example. In certain instances, the surgical instrument  2200  may comprise a positioning system (not shown) for sensing and recording the position of the longitudinally-movable drive member  2226  during a firing stroke of the firing drive system  2214 . In at least one example, the processor  2242  can be configured to detect a bailout error when one or more of the recorded positions of the longitudinally-movable drive member  2226  is not are accordance with a predetermined threshold, for example. 
     In any event, referring again to  FIG. 52 , when the processor  2242  detects a bailout error in the decision-making step  2254 , the processor  2242  may respond by stopping and/or disabling the motor  2216 , for example. In addition, in certain instances, the processor  2242  also may store a bailed out state in the memory  2240  after detecting the bailout error, as illustrated in  FIG. 52 . In other words, the processor  2242  may store in the memory  2240  a status indicating that a bailout error has been detected. As described above, the memory  2240  can be a non-volatile memory which may preserve the stored status that a bailout error has been detected when the surgical instrument  2200  is reset by the user, for example. 
     In various instances, the motor  2216  can be stopped and/or disabled by disconnecting the battery  2218  from the motor  2216 , for example. In various instances, the processor  2242  may employ the driver  2244  to stop and/or disable the motor  2216 . In certain instances, when the motor override circuit is utilized, the processor  2242  may employ the motor override circuit to stop and/or disable the motor  2216 . In certain instances, stopping and/or disabling the motor  2216  may prevent a user of the surgical instrument  2200  from using the motor  2216  at least until the manual bailout is performed, for example. The reader will appreciate that stopping and/or disabling the motor  2216  in response to the detection of a bailout error can be advantageous in protecting tissue captured by the surgical instrument  2200 . 
     Further to the above, referring still to  FIG. 52 , the module  2252  may include a decision-making step  2256  for detecting whether the bailout door  2232  is removed. As described above, the processor  2242  can be operationally coupled to the bailout door feedback element  2246  which can be configured to alert the processor  2242  as to whether the bailout door  2232  is removed. In certain instances, the processor  2242  can be programmed to detect that the bailout door  2232  is removed when the bailout door feedback element  2246  reports that the locking mechanism  2234  is unlocked, for example. In certain instances, the processor  2242  can be programmed to detect that the bailout door  2232  is removed when the bailout door feedback element  2246  reports that the bailout door  2232  is opened, for example. In certain instances, the processor  2242  can be programmed to detect that the bailout door  2232  is removed when the bailout door feedback element  2246  reports that the locking mechanism  2234  is unlocked and that the bailout door  2232  is opened, for example. 
     In various instances, referring still to  FIG. 52 , when the processor  2242  does not detect a bailout error in the decision-making step  2254  and does not detect that the bailout door  2232  is removed in the decision-making step  2256 , the processor  2242  may not interrupt the normal operation of the surgical instrument  2200  and may proceed with various clinical algorithms. In certain instances, when the processor  2242  does not detect a bailout error in the decision-making step  2254  but detects that the bailout door  2232  is removed in the decision-making step  2256 , the processor  2242  may respond by stopping and/or disabling the motor  2216 , as described above. In addition, in certain instances, the processor  2242  also may provide the user with instructions to reinstall the bailout door  2232 , as described in greater detail below. In certain instances, when the processor  2242  detects that the bailout door  2232  is reinstalled, while no bailout error is detected, the processor  2242  can be configured to reconnect the power to the motor  2216  and allow the user to continue with clinical algorithms, as illustrated in  FIG. 52 . 
     In certain instances, when the user does not reinstall the bailout door  2232 , the processor  2242  may not reconnect power to the motor  2216  and may continue providing the user with the instructions to reinstall the bailout door  2232 . In certain instances, when the user does not reinstall the bailout door  2232 , the processor  2242  may provide the user with a warning that the bailout door  2232  needs to be reinstalled in order to continue with the normal operation of the surgical instrument  2200 . In certain instances, the surgical instrument  2200  can be equipped with an override mechanism (not shown) to permit the user to reconnect power to the motor  2216  even when the bailout door  2216  is not installed. 
     In various instances, the processor  2242  can be configured to provide the user with a sensory feedback when the processor  2242  detects that the bailout door  2232  is removed. In various instances, the processor  2242  can be configured to provide the user with a sensory feedback when the processor  2242  detects that the bailout door  2232  is reinstalled. Various devices can be employed by the processor  2242  to provide the sensory feedback to the user. Such devices may comprise, for example, visual feedback devices such as display screens and/or LED indicators, for example. In certain instances, such devices may comprise audio feedback devices such as speakers and/or buzzers, for example. In certain instances, such devices may comprise tactile feedback devices such as haptic actuators, for example. In certain instances, such devices may comprise combinations of visual feedback devices, audio feedback devices, and/or tactile feedback devices. In certain instances, the processor  2242  may employ the display  2250  to instruct the user to reinstall the bailout door  2232 . For example, the processor  2242  may present an alert symbol next to an image of the bailout door  2232  to the user through the display  2250 , for example. In certain instances, the processor  2242  may present an animated image of the bailout door  2232  being installed, for example. Other images, symbols, and/or words can be displayed through the display  2250  to alert the user of the surgical instrument  2200  to reinstall the bailout door  2232 . 
     Referring again to  FIG. 52 , when a bailout error is detected, the processor  2242  may signal the user of the surgical instrument  2200  to perform the manual bailout using the bailout handle  2230 . In various instances, the processor  2242  can signal the user to perform the manual bailout by providing the user with a visual, audio, and/or tactile feedback, for example. In certain instances, as illustrated in  FIG. 52 , the processor  2242  can signal the user of the surgical instrument  2200  to perform the manual bailout by flashing a backlight of the display  2250 . In any event, the processor  2242  may then provide the user with instructions to perform the manual bailout. In various instances, as illustrated in  FIG. 52 , the instructions may depend on whether the bailout door  2232  is installed; a decision making step  2258  may determine the type of instructions provided to the user. In certain instances, when the processor  2242  detects that the bailout door  2232  is installed, the processor  2242  may provide the user with instructions to remove the bailout door  2232  and instructions to operate the bailout handle  2230 , for example. However, when the processor  2242  detects that the bailout door  2232  is removed, the processor  2242  may provide the user with the instructions to operate the bailout handle  2230  but not the instructions to remove the bailout door  2232 , for example. 
     Referring again to  FIG. 52 , in various instances, the instructions provided by the processor  2242  to the user to remove the bailout door  2232  and/or to operate the bailout handle  2230  may comprise one or more steps; the steps may be presented to the user in a chronological order. In certain instances, the steps may comprise actions to be performed by the user. In such instances, the user may proceed through the steps of the manual bailout by performing the actions presented in each of the steps. In certain instances, the actions required in one or more of the steps can be presented to the user in the form of animated images displayed on the display  2250 , for example. In certain instances, one or more of the steps can be presented to the user as messages which may include words, symbols, and/or images that guide the user through the manual bailout. In certain instances, one or more of the steps of performing the manual bailout can be combined in one or more messages, for example. In certain instances, each message may comprise a separate step, for example. 
     In certain instances, the steps and/or the messages providing the instructions for the manual bailout can be presented to the user in predetermined time intervals to allow the user sufficient time to comply with the presented steps and/or messages, for example. In certain instances, the processor  2242  can be programed to continue presenting a step and/or a message until feedback is received by the processor  2242  that the step has been performed. In certain instances, the feedback can be provided to the processor  2242  by the bailout door feedback element  2246 , for example. Other mechanisms and/or sensors can be employed by the processor  2242  to obtain feedback that a step has been completed. In at least one example, the user can be instructed to alert that processor  2242  when a step is completed by pressing an alert button, for example. In certain instances, the display  2250  may comprise a capacitive screen which may provide the user with an interface to alert the processor  2242  when a step is completed. For example, the user may press the capacitive screen to move to the next step of the manual bailout instructions after a current step is completed. 
     In certain instances, as illustrated in  FIG. 52 , after detecting that the bailout door  2232  is installed, the processor  2242  can be configured to employ the display  2250  to present an animated image  2260  depicting a hand moving toward the bailout door  2232 . The processor  2242  may continue to display the animated image  2260  for a time interval sufficient for the user to engage the bailout door  2232 , for example. In certain instances, the processor  2242  may then replace the animated image  2260  with an animated image  2262  depicting a finger engaging the bailout door locking mechanism  2234 , for example. The processor  2242  may continue to display the animated image  2262  for a time interval sufficient for the user to unlock the locking mechanism  2234 , for example. In certain instances, the processor  2242  may continue to display the animated image  2262  until the bailout door feedback element  2246  reports that the locking mechanism  2234  is unlocked, for example. In certain instances, the processor  2242  may continue to display the animated image  2262  until the user alerts the processor  2242  that the step of unlocking the locking mechanism  2234  is completed. 
     In any event, the processor  2242  may then replace the animated image  2262  with an animated image  2264  depicting a finger removing the bailout door  2232 , for example. The processor  2242  may continue to display the animated image  2264  for a time interval sufficient for the user to remove the bailout door  2232 , for example. In certain instances, the processor  2242  may continue to display the animated image  2264  until the bailout door feedback element  2246  reports that the bailout door  2232  is removed, for example. In certain instances, the processor  2242  may continue to display the animated image  2264  until the user alerts the processor  2242  that the step of removing the bailout door  2232  has been removed, for example. In certain instances, the processor  2242  can be configured to continue to repeat displaying the animated images  2260 ,  2262 , and  2246  in their respective order when the processor  2242  continues to detect that the bailout door is installed at the decision making step  2258 , for example. 
     Further to the above, after detecting that the bailout door  2232  is removed, the processor  2242  may proceed to guide the user through the steps of operating the bailout handle  2230 . In certain instances, the processor  2242  may replace the animated image  2264  with an animated image  2266  depicting a finger lifting the bailout handle  2230 , for example, into ratcheting engagement with the teeth  2224  in the drive member  2226 , as described above. The processor  2242  may continue to display the animated image  2266  for a time interval sufficient for the user to lift the bailout handle  2230 , for example. In certain instances, the processor  2242  may continue to display the animated image  2266  until the processor receives feedback that the bailout handle  2230  has been lifted. For example, the processor  2242  may continue to display the animated image  2266  until the user alerts the processor  2242  that the step of lifting the bailout handle  2230  has been removed. 
     In certain instances, as described above, the user can manually retract the drive member  2226  by using the bailout handle  2230  to ratchet the drive member  2226  in the proximal direction “P,” for example, to release tissue trapped by the end effector  2208 , for example. In such instances, the processor  2242  may replace the animated image  2266  with an animated image  2268  depicting a finger repeatedly pulling then pushing the bailout handle  2230 , for example, to simulate the ratcheting of the bailout handle  2230 . The processor  2242  may continue to display the animated image  2268  for a time interval sufficient for the user to ratchet the drive member  2226  to default position, for example. In certain instances, the processor  2242  may continue to display the animated image  2268  until the processor  2242  receives feedback that the drive member  2226  has been retracted. 
       FIG. 53  depicts a module  2270  which is similar in many respects to the module  2258 . For example, the module  2252  also can be stored in the memory  2240  and/or executed by the processor  2242 , for example, to alert, guide, and/or provide feedback to a user of the surgical instrument  2200  with regard to performing a manual bailout of the surgical instrument  2200 . In certain instances, the surgical instrument  2200  may not comprise a bailout door. In such circumstances, the module  2270  can be employed by the processor  2242  to provide the user with instructions as to how to operate the bailout handle  2230 , for example. 
     Referring again to the module  2270  depicted in  FIG. 53 , when the processor  2242  does not detect a bailout error in the decision-making step  2254  of the module  2270 , the processor  2242  may not interrupt the normal operation of the surgical instrument  2200  and may proceed with various clinical algorithms. However, when the processor  2242  detects a bailout error in the decision-making step  2254  of the module  2270 , the processor  2242  may respond by stopping and/or disabling the motor  2216 , for example. In addition, in certain instances, the processor  2242  also may store a bailed out state in the memory  2240  after detecting the bailout error, as illustrated in  FIG. 53 . In the absence of a bailout door, the processor  2242  may signal the user of the surgical instrument  2200  to perform the manual bailout, for example, by flashing the backlight of the display  2250 ; the processor  2242  may then proceed directly to providing the user with the instructions to operate the bailout handle  2230 , as described above. 
     The reader will appreciate that the steps depicted in  FIGS. 52 and/or 53  are illustrative examples of the instructions that can be provided to the user of the surgical instrument  2200  to perform a manual bailout. The modules  2252  and/or  2270  can be configured to provide more or less steps than those illustrated in  FIGS. 52 and 53 . The reader will also appreciate that the modules  2252  and/or  2270  are exemplary modules; various other modules can be executed by the processor  2242  to provide the user of the surgical instrument  2200  with instructions to perform the manual bailout. 
     In various instances, as described above, the processor  2242  can be configured to present to the user of the surgical instrument  2200  the steps and/or messages for performing a manual bailout in predetermined time intervals. Such time intervals may be the same or may vary depending on the complexity of the task to be performed by the user, for example. In certain instances, such time intervals can be any time interval in the range of about 1 second, for example, to about 10 minutes, for example. In certain instances, such time intervals can be any time interval in the range of about 1 second, for example, to about 1 minute, for example. Other time intervals are contemplated by the present disclosure. 
     In some instances, a power assembly, such as, for example the power assembly  2006  illustrated in  FIGS. 31-33B , is configured to monitor the number of uses of the power assembly  2006  and/or a surgical instrument  2000  coupled to the power assembly  2006 . The power assembly  2006  maintains a usage cycle count corresponding to the number of uses. The power assembly  2006  and/or the surgical instrument  2000  performs one or more actions based on the usage cycle count. For example, in some instances, when the usage cycle count exceeds a predetermined usage limit, the power assembly  2006  and/or a surgical instrument  2000  may disable the power assembly  2006 , disable the surgical instrument  2000 , indicate that a reconditioning or service cycle is required, provide a usage cycle count to an operator and/or a remote system, and/or perform any other suitable action. The usage cycle count is determined by any suitable system, such as, for example, a mechanical limiter, a usage cycle circuit, and/or any other suitable system coupled to the battery  2006  and/or the surgical instrument  2000 . 
       FIG. 54  illustrates one example of a power assembly  2400  comprising a usage cycle circuit  2402  configured to monitor a usage cycle count of the power assembly  2400 . The power assembly  2400  may be coupled to a surgical instrument  2410 . The usage cycle circuit  2402  comprises a processor  2404  and a use indicator  2406 . The use indicator  2406  is configured to provide a signal to the processor  2404  to indicate a use of the battery back  2400  and/or a surgical instrument  2410  coupled to the power assembly  2400 . A “use” may comprise any suitable action, condition, and/or parameter such as, for example, changing a modular component of a surgical instrument  2410 , deploying or firing a disposable component coupled to the surgical instrument  2410 , delivering electrosurgical energy from the surgical instrument  2410 , reconditioning the surgical instrument  2410  and/or the power assembly  2400 , exchanging the power assembly  2400 , recharging the power assembly  2400 , and/or exceeding a safety limitation of the surgical instrument  2410  and/or the battery back  2400 . 
     In some instances, a usage cycle, or use, is defined by one or more power assembly  2400  parameters. For example, in one instance, a usage cycle comprises using more than 5% of the total energy available from the power assembly  2400  when the power assembly  2400  is at a full charge level. In another instance, a usage cycle comprises a continuous energy drain from the power assembly  2400  exceeding a predetermined time limit. For example, a usage cycle may correspond to five minutes of continuous and/or total energy draw from the power assembly  2400 . In some instances, the power assembly  2400  comprises a usage cycle circuit  2402  having a continuous power draw to maintain one or more components of the usage cycle circuit  2402 , such as, for example, the use indicator  2406  and/or a counter  2408 , in an active state. 
     The processor  2404  maintains a usage cycle count. The usage cycle count indicates the number of uses detected by the use indicator  2406  for the power assembly  2400  and/or the surgical instrument  2410 . The processor  2404  may increment and/or decrement the usage cycle count based on input from the use indicator  2406 . The usage cycle count is used to control one or more operations of the power assembly  2400  and/or the surgical instrument  2410 . For example, in some instances, a power assembly  2400  is disabled when the usage cycle count exceeds a predetermined usage limit. Although the instances discussed herein are discussed with respect to incrementing the usage cycle count above a predetermined usage limit, those skilled in the art will recognize that the usage cycle count may start at a predetermined amount and may be decremented by the processor  2404 . In this instance, the processor  2404  initiates and/or prevents one or more operations of the power assembly  2400  when the usage cycle count falls below a predetermined usage limit. 
     The usage cycle count is maintained by a counter  2408 . The counter  2408  comprises any suitable circuit, such as, for example, a memory module, an analog counter, and/or any circuit configured to maintain a usage cycle count. In some instances, the counter  2408  is formed integrally with the processor  2404 . In other instances, the counter  2408  comprises a separate component, such as, for example, a solid state memory module. In some instances, the usage cycle count is provided to a remote system, such as, for example, a central database. The usage cycle count is transmitted by a communications module  2412  to the remote system. The communications module  2412  is configured to use any suitable communications medium, such as, for example, wired and/or wireless communication. In some instances, the communications module  2412  is configured to receive one or more instructions from the remote system, such as, for example, a control signal when the usage cycle count exceeds the predetermined usage limit. 
     In some instances, the use indicator  2406  is configured to monitor the number of modular components used with a surgical instrument  2410  coupled to the power assembly  2400 . A modular component may comprise, for example, a modular shaft, a modular end effector, and/or any other modular component. In some instances, the use indicator  2406  monitors the use of one or more disposable components, such as, for example, insertion and/or deployment of a staple cartridge within an end effector coupled to the surgical instrument  2410 . The use indicator  2406  comprises one or more sensors for detecting the exchange of one or more modular and/or disposable components of the surgical instrument  2410 . 
     In some instances, the use indicator  2406  is configured to monitor single patient surgical procedures performed while the power assembly  2400  is installed. For example, the use indicator  2406  may be configured to monitor firings of the surgical instrument  2410  while the power assembly  2400  is coupled to the surgical instrument  2410 . A firing may correspond to deployment of a staple cartridge, application of electrosurgical energy, and/or any other suitable surgical event. The use indicator  2406  may comprise one or more circuits for measuring the number of firings while the power assembly  2400  is installed. The use indicator  2406  provides a signal to the processor  2404  when a single patient procedure is performed and the processor  2404  increments the usage cycle count. 
     In some instances, the use indicator  2406  comprises a circuit configured to monitor one or more parameters of the power source  2414 , such as, for example, a current draw from the power source  2414 . The one or more parameters of the power source  2414  correspond to one or more operations performable by the surgical instrument  2410 , such as, for example, a cutting and sealing operation. The use indicator  2406  provides the one or more parameters to the processor  2404 , which increments the usage cycle count when the one or more parameters indicate that a procedure has been performed. 
     In some instances, the use indicator  2406  comprises a timing circuit configured to increment a usage cycle count after a predetermined time period. The predetermined time period corresponds to a single patient procedure time, which is the time required for an operator to perform a procedure, such as, for example, a cutting and sealing procedure. When the power assembly  2400  is coupled to the surgical instrument  2410 , the processor  2404  polls the use indicator  2406  to determine when the single patient procedure time has expired. When the predetermined time period has elapsed, the processor  2404  increments the usage cycle count. After incrementing the usage cycle count, the processor  2404  resets the timing circuit of the use indicator  2406 . 
     In some instances, the use indicator  2406  comprises a time constant that approximates the single patient procedure time.  FIG. 55  illustrates one instance of power assembly  2500  comprising a usage cycle circuit  2502  having a resistor-capacitor (RC) timing circuit  2506 . The RC timing circuit  2506  comprises a time constant defined by a resistor-capacitor pair. The time constant is defined by the values of the resistor  2518  and the capacitor  2516 . When the power assembly  2500  is installed in a surgical instrument, a processor  2504  polls the RC timing circuit  2506 . When one or more parameters of the RC timing circuit  2506  are below a predetermined threshold, the processor  2504  increments the usage cycle count. For example, the processor  2504  may poll the voltage of the capacitor  2518  of the resistor-capacitor pair  2506 . When the voltage of the capacitor  2518  is below a predetermined threshold, the processor  2504  increment the usage cycle count. The processor  2504  may be coupled to the RC timing circuit  2506  by, for example, and ADC  2520 . After incrementing the usage cycle count, the processor  2504  turns on a transistor  2522  to connect the RC timing circuit  2506  to a power source  2514  to charge the capacitor  2518  of the RC timing circuit  2506 . Once the capacitor  2518  is fully charged, the transistor  2522  is opened and the RC timing circuit  2506  is allowed to discharge, as governed by the time constant, to indicate a subsequent single patient procedure. 
       FIG. 56  illustrates one instance of a power assembly  2550  comprising a usage cycle circuit  2552  having a rechargeable battery  2564  and a clock  2560 . When the power assembly  2550  is installed in a surgical instrument, the rechargeable battery  2564  is charged by the power source  2558 . The rechargeable battery  2564  comprises enough power to run the clock  2560  for at least the single patient procedure time. The clock  2560  may comprise a real time clock, a processor configured to implement a time function, or any other suitable timing circuit. The processor  2554  receives a signal from the clock  2560  and increments the usage cycle count when the clock  2560  indicates that the single patient procedure time has been exceeded. The processor  2554  resets the clock  2560  after incrementing the usage cycle count. For example, in one instance, the processor  2554  closes a transistor  2562  to recharge the rechargeable battery  2564 . Once the rechargeable battery  2564  is fully charged, the processor  2554  opens the transistor  2562 , and allows the clock  2560  to run while the rechargeable battery  2564  discharges. 
     Referring back to  FIG. 54 , in some instances, the use indicator  2406  comprises a sensor configured to monitor one or more environmental conditions experienced by the power assembly  2400 . For example, the use indicator  2406  may comprise an accelerometer. The accelerometer is configured to monitor acceleration of the power assembly  2400 . The power assembly  2400  comprises a maximum acceleration tolerance. Acceleration above a predetermined threshold indicates, for example, that the power assembly  2400  has been dropped. When the use indicator  2406  detects acceleration above the maximum acceleration tolerance, the processor  2404  increments a usage cycle count. In some instances, the use indicator  2406  comprises a moisture sensor. The moisture sensor is configured to indicate when the power assembly  2400  has been exposed to moisture. The moisture sensor may comprise, for example, an immersion sensor configured to indicate when the power assembly  2400  has been fully immersed in a cleaning fluid, a moisture sensor configured to indicate when moisture is in contact with the power assembly  2400  during use, and/or any other suitable moisture sensor. 
     In some instances, the use indicator  2406  comprises a chemical exposure sensor. The chemical exposure sensor is configured to indicate when the power assembly  2400  has come into contact with harmful and/or dangerous chemicals. For example, during a sterilization procedure, an inappropriate chemical may be used that leads to degradation of the power assembly  2400 . The processor  2404  increments the usage cycle count when the use indicator  2406  detects an inappropriate chemical. 
     In some instances, the usage cycle circuit  2402  is configured to monitor the number of reconditioning cycles experienced by the power assembly  2400 . A reconditioning cycle may comprise, for example, a cleaning cycle, a sterilization cycle, a charging cycle, routine and/or preventative maintenance, and/or any other suitable reconditioning cycle. The use indicator  2406  is configured to detect a reconditioning cycle. For example, the use indicator  2406  may comprise a moisture sensor to detect a cleaning and/or sterilization cycle. In some instances, the usage cycle circuit  2402  monitors the number of reconditioning cycles experienced by the power assembly  2400  and disables the power assembly  2400  after the number of reconditioning cycles exceeds a predetermined threshold. 
     The usage cycle circuit  2402  may be configured to monitor the number of power assembly  2400  exchanges. The usage cycle circuit  2402  increments the usage cycle count each time the power assembly  2400  is exchanged. When the maximum number of exchanges is exceeded, the usage cycle circuit  2402  locks out the power assembly  2400  and/or the surgical instrument  2410 . In some instances, when the power assembly  2400  is coupled the surgical instrument  2410 , the usage cycle circuit  2402  identifies the serial number of the power assembly  2400  and locks the power assembly  2400  such that the power assembly  2400  is usable only with the surgical instrument  2410 . In some instances, the usage cycle circuit  2402  increments the usage cycle each time the power assembly  2400  is removed from and/or coupled to the surgical instrument  2410 . 
     In some instances, the usage cycle count corresponds to sterilization of the power assembly  2400 . The use indicator  2406  comprises a sensor configured to detect one or more parameters of a sterilization cycle, such as, for example, a temperature parameter, a chemical parameter, a moisture parameter, and/or any other suitable parameter. The processor  2404  increments the usage cycle count when a sterilization parameter is detected. The usage cycle circuit  2402  disables the power assembly  2400  after a predetermined number of sterilizations. In some instances, the usage cycle circuit  2402  is reset during a sterilization cycle, a voltage sensor to detect a recharge cycle, and/or any suitable sensor. The processor  2404  increments the usage cycle count when a reconditioning cycle is detected. The usage cycle circuit  2402  is disabled when a sterilization cycle is detected. The usage cycle circuit  2402  is reactivated and/or reset when the power assembly  2400  is coupled to the surgical instrument  2410 . In some instances, the use indicator comprises a zero power indicator. The zero power indicator changes state during a sterilization cycle and is checked by the processor  2404  when the power assembly  2400  is coupled to a surgical instrument  2410 . When the zero power indicator indicates that a sterilization cycle has occurred, the processor  2404  increments the usage cycle count. 
     A counter  2408  maintains the usage cycle count. In some instances, the counter  2408  comprises a non-volatile memory module. The processor  2404  increments the usage cycle count stored in the non-volatile memory module each time a usage cycle is detected. The memory module may be accessed by the processor  2404  and/or a control circuit, such as, for example, the control circuit  1100 . When the usage cycle count exceeds a predetermined threshold, the processor  2404  disables the power assembly  2400 . In some instances, the usage cycle count is maintained by a plurality of circuit components. For example, in one instance, the counter  2408  comprises a resistor (or fuse) pack. After each use of the power assembly  2400 , a resistor (or fuse) is burned to an open position, changing the resistance of the resistor pack. The power assembly  2400  and/or the surgical instrument  2410  reads the remaining resistance. When the last resistor of the resistor pack is burned out, the resistor pack has a predetermined resistance, such as, for example, an infinite resistance corresponding to an open circuit, which indicates that the power assembly  2400  has reached its usage limit. In some instances, the resistance of the resistor pack is used to derive the number of uses remaining. 
     In some instances, the usage cycle circuit  2402  prevents further use of the power assembly  2400  and/or the surgical instrument  2410  when the usage cycle count exceeds a predetermined usage limit. In one instance, the usage cycle count associated with the power assembly  2400  is provided to an operator, for example, utilizing a screen formed integrally with the surgical instrument  2410 . The surgical instrument  2410  provides an indication to the operator that the usage cycle count has exceeded a predetermined limit for the power assembly  2400 , and prevents further operation of the surgical instrument  2410 . 
     In some instances, the usage cycle circuit  2402  is configured to physically prevent operation when the predetermined usage limit is reached. For example, the power assembly  2400  may comprise a shield configured to deploy over contacts of the power assembly  2400  when the usage cycle count exceeds the predetermined usage limit. The shield prevents recharge and use of the power assembly  2400  by covering the electrical connections of the power assembly  2400 . 
     In some instances, the usage cycle circuit  2402  is located at least partially within the surgical instrument  2410  and is configured to maintain a usage cycle count for the surgical instrument  2410 .  FIG. 54  illustrates one or more components of the usage cycle circuit  2402  within the surgical instrument  2410  in phantom, illustrating the alternative positioning of the usage cycle circuit  2402 . When a predetermined usage limit of the surgical instrument  2410  is exceeded, the usage cycle circuit  2402  disables and/or prevents operation of the surgical instrument  2410 . The usage cycle count is incremented by the usage cycle circuit  2402  when the use indicator  2406  detects a specific event and/or requirement, such as, for example, firing of the surgical instrument  2410 , a predetermined time period corresponding to a single patient procedure time, based on one or more motor parameters of the surgical instrument  2410 , in response to a system diagnostic indicating that one or more predetermined thresholds are met, and/or any other suitable requirement. As discussed above, in some instances, the use indicator  2406  comprises a timing circuit corresponding to a single patient procedure time. In other instances, the use indicator  2406  comprises one or more sensors configured to detect a specific event and/or condition of the surgical instrument  2410 . 
     In some instances, the usage cycle circuit  2402  is configured to prevent operation of the surgical instrument  2410  after the predetermined usage limit is reached. In some instances, the surgical instrument  2410  comprises a visible indicator to indicate when the predetermined usage limit has been reached and/or exceeded. For example, a flag, such as a red flag, may pop-up from the surgical instrument  2410 , such as from the handle, to provide a visual indication to the operator that the surgical instrument  2410  has exceeded the predetermined usage limit. As another example, the usage cycle circuit  2402  may be coupled to a display formed integrally with the surgical instrument  2410 . The usage cycle circuit  2402  displays a message indicating that the predetermined usage limit has been exceeded. The surgical instrument  2410  may provide an audible indication to the operator that the predetermined usage limit has been exceeded. For example, in one instance, the surgical instrument  2410  emits an audible tone when the predetermined usage limit is exceeded and the power assembly  2400  is removed from the surgical instrument  2410 . The audible tone indicates the last use of the surgical instrument  2410  and indicates that the surgical instrument  2410  should be disposed or reconditioned. 
     In some instances, the usage cycle circuit  2402  is configured to transmit the usage cycle count of the surgical instrument  2410  to a remote location, such as, for example, a central database. The usage cycle circuit  2402  comprises a communications module  2412  configured to transmit the usage cycle count to the remote location. The communications module  2412  may utilize any suitable communications system, such as, for example, wired or wireless communications system. The remote location may comprise a central database configured to maintain usage information. In some instances, when the power assembly  2400  is coupled to the surgical instrument  2410 , the power assembly  2400  records a serial number of the surgical instrument  2410 . The serial number is transmitted to the central database, for example, when the power assembly  2400  is coupled to a charger. In some instances, the central database maintains a count corresponding to each use of the surgical instrument  2410 . For example, a bar code associated with the surgical instrument  2410  may be scanned each time the surgical instrument  2410  is used. When the use count exceeds a predetermined usage limit, the central database provides a signal to the surgical instrument  2410  indicating that the surgical instrument  2410  should be discarded. 
     The surgical instrument  2410  may be configured to lock and/or prevent operation of the surgical instrument  2410  when the usage cycle count exceeds a predetermined usage limit. In some instances, the surgical instrument  2410  comprises a disposable instrument and is discarded after the usage cycle count exceeds the predetermined usage limit. In other instances, the surgical instrument  2410  comprises a reusable surgical instrument which may be reconditioned after the usage cycle count exceeds the predetermined usage limit. The surgical instrument  2410  initiates a reversible lockout after the predetermined usage limit is met. A technician reconditions the surgical instrument  2410  and releases the lockout, for example, utilizing a specialized technician key configured to reset the usage cycle circuit  2402 . 
     In some instances, the power assembly  2400  is charged and sterilized simultaneously prior to use.  FIG. 57  illustrates one instance of a combined sterilization and charging system  2600  configured to charge and sterilize a battery  2602  simultaneously. The combined sterilization and charging system  2600  comprises a sterilization chamber  2604 . A battery  2602  is placed within the sterilization chamber  2604 . In some instances, the battery  2602  is coupled to a surgical instrument. A charging cable  2606  is mounted through a wall  2608  of the sterilization chamber  2604 . The wall  2608  is sealed around the charging cable  2606  to maintain a sterile environment within the sterilization chamber  2604  during sterilization. The charging cable  2606  comprises a first end configured to couple to the power assembly  2602  within the sterilization chamber  2604  and a second end coupled to a battery charger  2610  located outside of the sterilization chamber  2604 . Because the charging cable  2606  passes through the wall  2608  of the sterilization chamber  2604  while maintaining a sterile environment within the sterilization chamber  2604 , the power assembly  2602  may be charged and sterilized simultaneously. 
     The charging profile applied by the battery charger  2610  is configured to match the sterilization cycle of the sterilization chamber  2604 . For example, in one instance, a sterilization procedure time is about 28 to 38 minutes. The battery charger  2610  is configured to provide a charging profile that charges the battery during the sterilization procedure time. In some instances, the charging profile may extend over a cooling-off period following the sterilization procedure. The charging profile may be adjusted by the battery charger  2610  based on feedback from the power assembly  2602  and/or the sterilization chamber  2604 . For example, in one instance, a sensor  2612  is located within the sterilization chamber  2604 . The sensor  2612  is configured to monitor one or more characteristics of the sterilization chamber  2604 , such as, for example, chemicals present in the sterilization chamber  2604 , temperature of the sterilization chamber  2604 , and/or any other suitable characteristic of the sterilization chamber  2604 . The sensor  2612  is coupled to the battery charger  2610  by a cable  2614  extending through the wall  2608  of the sterilization chamber  2604 . The cable  2614  is sealed such that the sterilization chamber  2604  may maintain a sterile environment. The battery charger  2610  adjusts the charging profile based on feedback from the sensor  2614 . For example, in one instance, the battery charger  2610  receives temperature data from the sensor  2612  and adjusts the charging profile when the temperature of the sterilization chamber  2604  and/or the power assembly  2602  exceeds a predetermined temperature. As another example, the battery charger  2610  receives chemical composition information from the sensor  2612  and prevents charging of the power assembly  2602  when a chemical, such as, for example, H 2 O 2 , approaches explosive limits. 
       FIG. 58  illustrates one instance of a combination sterilization and charging system  2650  configured for a power assembly  2652  having a battery charger  2660  formed integrally therewith. An alternating current (AC) source  2666  is located outside of the sterilization chamber  2654  and is coupled the battery charger  2660  by an AC cable  2656  mounted through a wall  2658  of the sterilization chamber  2654 . The wall  2658  is sealed around the AC cable  2656 . The battery charger  2660  operates similar to the battery charger  2610  illustrated in  FIG. 57 . In some instances, the battery charger  2660  receives feedback from a sensor  2662  located within the sterilization chamber  2654  and coupled to the battery charger  2660  by a cable  2664 . 
     In various instances, a surgical system can include a magnet and a sensor. In combination, the magnet and the sensor can cooperate to detect various conditions of a fastener cartridge, such as the presence of a fastener cartridge in an end effector of the surgical instrument, the type of fastener cartridge loaded in the end effector, and/or the firing state of a loaded fastener cartridge, for example. Referring now to  FIG. 62 , a jaw  902  of an end effector  900  can comprise a magnet  910 , for example, and a fastener cartridge  920  can comprise a sensor  930 , for example. In various instances, the magnet  910  can be positioned at the distal end  906  of an elongate channel  904  sized and configured to receive the fastener cartridge  920 . Furthermore, the sensor  930  can be at least partially embedded or retained in the distal end  926  of the nose  924  of the fastener cartridge  920 , for example. In various instances, the sensor  924  can be in signal communication with the microcontroller of the surgical instrument. 
     In various circumstances, the sensor  930  can detect the presence of the magnet  910  when the fastener cartridge  920  is positioned in the elongate channel  904  of the jaw  902 . The sensor  930  can detect when the fastener cartridge  920  is improperly positioned in the elongate channel  904  and/or not loaded into the elongate channel  904 , for example, and can communicate the cartridge loading state to the microcontroller of the surgical system, for example. In certain instances, the magnet  910  can be positioned in the fastener cartridge  920 , for example, and the sensor  930  can be positioned in the end effector  900 , for example. In various instances, the sensor  930  can detect the type of fastener cartridge  920  loaded in the end effector  900 . For example, different types of fastener cartridges can have different magnetic arrangements, such as different placement(s) relative to the cartridge body or other cartridge components, different polarities, and/or different magnetic strengths, for example. In such instances, the sensor  930  can detect the type of cartridge, e.g., the cartridge length, the number of fasteners and/or the fastener height(s), positioned in the jaw  902  based on the detected magnetic signal. Additionally or alternatively, the sensor  930  can detect if the fastener cartridge  920  is properly seated in the end effector  900 . For example, the end effector  900  and the fastener cartridge  920  can comprise a plurality of magnets and/or a plurality of sensors and, in certain instances, the sensor(s) can detect whether the fastener cartridge  920  is properly positioned and/or aligned based on the position of multiple magnets relative to the sensor(s), for example. 
     Referring now to  FIG. 63 , in certain instances, an end effector  3000  can include a plurality of magnets and a plurality of sensors. For example, a jaw  3002  can include a plurality of magnets  3010 ,  3012  positioned at the distal end  3006  thereof. Moreover, the fastener cartridge  3020  can include a plurality of sensors  3030 ,  3032  positioned at the distal end  3026  of the nose  3024 , for example. In certain instances, the sensors  3030 ,  3032  can detect the presence of the fastener cartridge  3020  in the elongate channel  3004  of the jaw  3002 . In various instances, the sensors  3030 ,  3032  can comprise Hall Effect sensors, for example. Various sensors are described in U.S. Pat. No. 8,210,411, filed Sep. 23, 2008, and entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT. U.S. Pat. No. 8,210,411, filed Sep. 23, 2008, and entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT, is hereby incorporated by reference in its entirety. The addition of an additional sensor or sensors can provide a greater bandwidth signal, for example, which can provide further and/or improved information to the microcontroller of the surgical instrument. Additionally or alternatively, additional sensors can determine if the fastener cartridge  3020  is properly seated in the elongate channel of the jaw  3002 , for example. 
     In various instances, a magnet can be positioned on a moveable component of a fastener cartridge. For example, a magnet can be positioned on a component of the fastener cartridge that moves during a firing stroke. In such instances, a sensor in the end effector can detect the firing state of the fastener cartridge. For example, referring now to  FIG. 64 , a magnet  3130  can be positioned on the sled  3122  of a fastener cartridge  3120 . Moreover, a sensor  1110  can be positioned in the jaw  3102  of the end effector  3100 . In various circumstances, the sled  3122  can translate during a firing stroke. Moreover, in certain instances, the sled  3120  can remain at the distal end of the fastener cartridge  3120  after the firing stroke. Stated differently, after the cartridge has been fired, the sled  3120  can remain at the distal end of the fastener cartridge  3120 . Accordingly, the sensor  3110  can detect the position of the magnet  3130  and the corresponding sled  3120  to determine the firing state of the fastener cartridge  3120 . For example, when the sensor  3110  detects the proximal position of the magnet  3130 , the fastener cartridge  3120  can be unfired and ready to fire, for example, and when the sensor  3110  detects the distal position of the magnet  3130 , the fastener cartridge  3120  can be spent, for example. Referring now to  FIG. 65 , in various instances, a jaw  3202  of an end effector  3200  can include a plurality of sensors  3210 ,  3212 . For example, a proximal sensor  3212  can be positioned in the proximal portion of the jaw  3202 , and a distal sensor  3210  can be positioned in the distal portion of the jaw  3202 , for example. In such instances, the sensors  3210 ,  3212  can detect the position of the sled  3122  as the sled  3122  moves during a firing stroke, for example. In various instances, the sensors  3210 ,  3212  can comprise Hall Effect sensors, for example. 
     Additionally or alternatively, an end effector can include a plurality of electrical contacts, which can detect the presence and/or firing state of a fastener cartridge. Referring now to  FIG. 66 , an end effector  3300  can include a jaw  3302  defining a channel  3304  configured to receive a fastener cartridge  3320 . In various instances, the jaw  3302  and the fastener cartridge  3320  can comprise electrical contacts. For example, the elongate channel  3304  can define a bottom surface  3306 , and an electrical contact  3310  can be positioned on the bottom surface  3306 . In various instances, a plurality of electrical contacts  3310  can be defined in the elongate channel  3304 . The electrical contacts  3310  can form part of a firing-state circuit  3340 , which can be in signal communication with a microcontroller of the surgical system. For example, the electrical contacts  3310  can be electrically coupled to and/or in communication with a power supply, and can form electrically active ends of an open circuit, for example. In some instances, one of the electrical contacts  3310  can be powered such that a voltage potential is created intermediate the electrical contacts  3310 . In certain instances, one of the contacts can be coupled to an output channel of the microprocessor, for example, which can apply a voltage potential to the contact. Another contact can be coupled to an input channel of the microprocessor, for example. In certain instances, the electrical contacts  3310  can be insulated from the frame  3306  of the jaw  3302 . Referring still to  FIG. 66 , the fastener cartridge  3320  can also include an electrical contact  3330 , or a plurality of electrical contacts, for example. In various instances, the electrical contact  3330  can be positioned on a moveable element of the fastener cartridge  3320 . For example, the electrical contact  3330  can be positioned on the sled  3322  of the fastener cartridge  3320 , and thus, the electrical contact  3330  can move in the fastener cartridge  3320  during a firing stroke. 
     In various instances, the electrical contact  3330  can comprise a metallic bar or plate on the sled  3320 , for example. The electrical contact  3330  in the fastener cartridge  3320  can cooperate with the electrical contact(s)  3310  in the end effector  3300 , for example. In certain circumstances, the electrical contact  3330  can contact the electrical contact(s)  3310  when the sled  3322  is positioned in a particular position, or a range of positions, in the fastener cartridge  3320 . For example, the electrical contact  3330  can contact the electrical contacts  3310  when the sled  3322  is unfired, and thus, positioned in a proximal position in the fastener cartridge  3320 . In such circumstances, the electrical contact  3330  can close the circuit between the electrical contacts  3310 , for example. Moreover, the firing-state circuit  3340  can communicate the closed circuit, i.e., the unfired cartridge indication, to the microcontroller of the surgical system. In such instances, when the sled  3322  is fired distally during a firing stroke, the electrical contact  3330  can move out of electrically contact with the electrical contacts  3310 , for example. Accordingly, the firing-state circuit  3340  can communicate the open circuit, i.e., the fired cartridge indication, to the microcontroller of the surgical system. In certain circumstances, the microcontroller may only initiate a firing stroke when an unspent cartridge is indicated by the firing-state circuit  3340 , for example. In various instances, the electrical contact  3330  can comprise an electromechanical fuse. In such instances, the fuse can break or short when the sled  3322  is fired through a firing stroke, for example. 
     Additionally or alternatively, referring now to  FIG. 67 , an end effector  3400  can include a jaw  3402  and a cartridge-present circuit  3440 . In various instances, the jaw  3402  can comprise an electrical contact  3410 , or a plurality of electrical contacts  3410 , in an elongate channel  3404  thereof, for example. Furthermore, a fastener cartridge  3420  can include an electrical contact  3430 , or a plurality of electrical contacts  3430 , on an outer surface of the fastener cartridge  3420 . In various instances, the electrical contacts  3430  can be positioned and/or mounted to a fixed or stationary component of the fastener cartridge  3420 , for example. In various circumstances, the electrical contacts  3430  of the fastener cartridge  3420  can contact the electrical contacts  3410  of the end effector  3400  when the fastener cartridge  3420  is loaded into the elongate channel  3404 , for example. Prior to placement of the fastener cartridge  3420  in the elongate channel  3404 , the cartridge-present circuit  3440  can be an open circuit, for example. When the fastener cartridge  3420  is properly seated in the jaw  3402 , the electrical contacts  3410  and  3430  can form the closed cartridge-present circuit  3440 . In instances where the jaw  3402  and/or the fastener cartridge  3420  comprise a plurality of electrical contacts  3410 ,  3430 , the cartridge-present circuit  3440  can comprise a plurality of circuits. Moreover, in certain instances, the cartridge-present circuit  3440  can identify the type of cartridge loaded in the jaw  3402  based on the number and/or arrangement of electrical contacts  3430  on the fastener cartridge  3420 , for example, and the corresponding open and/or closed circuits of the cartridge-present circuit  3440 , for example. 
     Moreover, the electrical contacts  3410  in the jaw  3402  can be in signal communication with the microcontroller of the surgical system. The electrical contacts  3410  can be wired to a power source, for example, and/or can communicate with the microcontroller via a wired and/or wireless connection, for example. In various instances, the cartridge-present circuit  3440  can communicate the cartridge presence or absence to the microcontroller of the surgical system. In various instances, a firing stroke may be prevented when the cartridge-present circuit  3440  indicates the absence of a fastener cartridge in the end effector jaw  3402 , for example. Moreover, a firing stroke may be permitted when the cartridge—present circuit  3440  indicates the presence of a fastener cartridge  3420  in the end effector jaw  3402 . 
     As described throughout the present disclosure, various sensors, programs, and circuits can detect and measure numerous characteristics of the surgical instrument and/or components thereof, surgical use or operation, and/or the tissue and/or operating site. For example, tissue thickness, the identification of the instrument components, usage and feedback data from surgical functions, and error or fault indications can be detected by the surgical instrument. In certain instances, the fastener cartridge can include a nonvolatile memory unit, which can be embedded or removably coupled to the fastener cartridge, for example. Such a nonvolatile memory unit can be in signal communication with the microcontroller via hardware, such as the electrical contacts described herein, radio frequency, or various other suitable forms of data transmission. In such instances, the microcontroller can communicate data and feedback to the nonvolatile memory unit in the fastener cartridge, and thus, the fastener cartridge can store information. In various instances, the information can be securely stored and access thereto can be restricted as suitable and appropriate for the circumstances. 
     In certain instances, the nonvolatile memory unit can comprise information regarding the fastener cartridge characteristics and/or the compatibility thereof with various other components of the modular surgical system. For example, when the fastener cartridge is loaded into an end effector, the nonvolatile memory unit can provide compatibility information to the microcontroller of the surgical system. In such instances, the microcontroller can verify the validity or compatibility of the modular assembly. For example, the microcontroller can confirm that the handle component can fire the fastener cartridge and/or that the fastener cartridge appropriate fits the end effector, for example. In certain circumstances, the microcontroller can communicate the compatibility or lack thereof to the operator of the surgical system, and/or may prevent a surgical function if the modular components are incompatible, for example. 
     As described herein, the surgical instrument can include a sensor, which can cooperate with a magnet to detect various characteristics of the surgical instrument, operation, and surgical site. In certain instances, the sensor can comprise a Hall Effect sensor and, in other instances, the sensor can comprise a magnetoresistive sensor as depicted in  FIGS. 68(A)-68(C) , for example. As described in greater detail herein, a surgical end effector can comprise a first jaw, which can be configured to receive a fastener cartridge, and a second jaw. The first jaw and/or the fastener cartridge can comprise a magnetic element, such as a permanent magnet, for example, and the second jaw can comprise a magnetoresistive sensor, for example. In other instances, the first jaw and/or the fastener cartridge can comprise a magnetoresistive sensor, for example, and the second jaw can comprise a magnetic element. The magnetoresistive sensor may have various characteristics listed in the table in  FIG. 68C , for example, and/or similar specifications, for example. In certain instances, the change in resistance caused by movement of the magnetic element relative to the magnetoresistive sensor can affect and/or vary the properties of the magnetic circuit depicted in  FIG. 68B , for example. 
     In various instances, the magnetoresistive sensor can detect the position of the magnetic element, and thus, can detect the thickness of tissue clamped between the opposing first and second jaws, for example. The magnetoresistive sensor can be in signal communication with the microcontroller, and the magnetoresistive sensor can wirelessly transmit data to an antenna in signal communication with the microcontroller, for example. In various instances, a passive circuit can comprise the magnetoresistive sensor. Moreover, the antenna can be positioned in the end effector, and can detect a wireless signal from the magnetoresistive sensor and/or microprocessor operably coupled thereto, for example. In such circumstances, an exposed electrical connection between the end effector comprising the antenna, for example, and the fastener cartridge comprising the magnetoresistive sensor, for example, can be avoided. Furthermore, in various instances, the antenna can be wired and/or in wireless communication with the microcontroller of the surgical instrument. 
     Tissue can contain fluid and, when the tissue is compressed, the fluid may be pressed from the compressed tissue. For example, when tissue is clamped between opposing jaws of a surgical end effector, fluid may flow and/or be displaced from the clamped tissue. Fluid flow or displacement in clamped tissue can depend on various characteristics of the tissue, such as the thickness and/or type of tissue, as well as various characteristics of the surgical operation, such as the desired tissue compression and/or the elapsed clamping time, for example. In various instances, fluid displacement between the opposing jaws of an end effector may contribute to malformation of staples formed between the opposing jaws. For example, the displacement of fluid during and/or following staple formation can induce bending and/or other uncontrolled movement of a staple away from its desired or intended formation. Accordingly, in various instances, it may be desirable to control the firing stroke, e.g., to control the firing speed, in relationship to the detected fluid flow, or lack thereof, intermediate opposing jaws of a surgical end effector. 
     In various instances, the fluid displacement in clamped tissue can be determined or approximated by various measurable and/or detectable tissue characteristics. For example, the degree of tissue compression can correspond to the degree of fluid displacement in the clamped tissue. In various instances, a higher degree of tissue compression can correspond to more fluid flow, for example, and a reduced degree of tissue compression can correspond to less fluid flow, for example. In various circumstances, a sensor positioned in the end effector jaws can detect the force exerted on the jaws by the compressed tissue. Additionally or alternatively, a sensor on or operably associated with the cutting element can detect the resistance on the cutting element as the cutting element is advanced through, and transects, the clamped tissue. In such circumstances, the detected cutting and/or firing resistance can correspond to the degree of tissue compression. When tissue compression is high, for example, the cutting element resistance can be greater, and when tissue compression is lower, for example, the cutting element resistance can be reduced. Correspondingly, the cutting element resistance can indicate the amount of fluid displacement. 
     In certain instances, the fluid displacement in clamped tissue can be determined or approximated by the force required to fire the cutting element, i.e., the force-to-fire. The force-to-fire can correspond to the cutting element resistance, for example. Furthermore, the force-to-fire can be measured or approximated by a microcontroller in signal communication with the electric motor that drives the cutting element. For example, where the cutting element resistance is higher, the electric motor can require more current to drive the cutting element through the tissue. Similarly, if the cutting element resistance is lower, the electric motor can require less current to drive the cutting element through the tissue. In such instances, the microcontroller can detect the amount of current drawn by the electric motor during the firing stroke. For example, the microcontroller can include a current sensor, which can detect the current utilized to fire the cutting element through the tissue, for example. 
     Referring now to  FIG. 60 , a surgical instrument assembly or system can be configured to detect the compressive force in the clamped tissue. For example, in various instances, an electric motor can drive the firing element, and a microcontroller can be in signal communication with the electric motor. As the electric motor drives the firing element, the microcontroller can determine the current drawn by the electric motor, for example. In such instances, the force-to-fire can correspond to the current drawn by the electric motor throughout the firing stroke, as described above. Referring still to  FIG. 60 , at step  3501 , the microcontroller of the surgical instrument can determine if the current drawn by the electric motor increases during the firing stroke and, if so, can calculate the percentage increase of the current. 
     In various instances, the microcontroller can compare the current draw increase during the firing stroke to a predefined threshold value. For example, the predefined threshold value can be 5%, 10%, 25%, 50% and/or 100%, for example, and the microcontroller can compare the current increase detected during a firing stroke to the predefined threshold value. In other instances, the threshold increase can be a value or range of values between 5% and 100%, and, in still other instances, the threshold increase can be less than 5% or greater than 100%, for example. For example, if the predefined threshold value is 50%, the microcontroller can compare the percentage of current draw change to 50%, for example. In certain instances, the microcontroller can determine if the current drawn by the electric motor during the firing stroke exceeds a percentage of the maximum current or a baseline value. For example, the microcontroller can determine if the current exceeds 5%, 10%, 25%, 50% and/or 100% of the maximum motor current. In other instances, the microcontroller can compare the current drawn by the electric motor during the firing stroke to a predefined baseline value, for example. 
     In various instances, the microcontroller can utilize an algorithm to determine the change in current drawn by the electric motor during a firing stroke. For example, the current sensor can detect the current drawn by the electric motor at various times and/or intervals during the firing stroke. The current sensor can continually detect the current drawn by the electric motor and/or can intermittently detect the current draw by the electric motor. In various instances, the algorithm can compare the most recent current reading to the immediately proceeding current reading, for example. Additionally or alternatively, the algorithm can compare a sample reading within a time period X to a previous current reading. For example, the algorithm can compare the sample reading to a previous sample reading within a previous time period X, such as the immediately proceeding time period X, for example. In other instances, the algorithm can calculate the trending average of current drawn by the motor. The algorithm can calculate the average current draw during a time period X that includes the most recent current reading, for example, and can compare that average current draw to the average current draw during an immediately proceeding time period time X, for example. 
     Referring still to  FIG. 60 , if the microcontroller detects a current increase that is greater than the threshold change or value, the microcontroller can proceed to step  3503 , and the firing speed of the firing element can be reduced. For example, the microcontroller can communicate with the electric motor to slow the firing speed of the firing element. For example, the firing speed can be reduced by a predefined step unit and/or a predefined percentage. In various instances, the microcontroller can comprise a velocity control module, which can affect changes in the cutting element speed and/or can maintain the cutting element speed. The velocity control module can comprise a resistor, a variable resistor, a pulse width modulation circuit, and/or a frequency modulation circuit, for example. Referring still to  FIG. 60 , if the current increase is less than the threshold value, the microcontroller can proceed to step  3505 , wherein the firing speed of the firing element can be maintained, for example. In various circumstances, the microcontroller can continue to monitor the current drawn by the electric motor and changes thereto during at least a portion of the firing stroke. Moreover, the microcontroller and/or velocity control module thereof can adjust the firing element velocity throughout the firing stroke in accordance with the detected current draw. In such instances, controlling the firing speed based on the approximated fluid flow or displacement in the clamped tissue, for example, can reduce the incidence of staple malformation in the clamped tissue. 
     Referring now to  FIG. 61 , in various instances, the microcontroller can adjust the firing element velocity by pausing the firing element for a predefined period of time. For example, similar to the embodiment depicted in  FIG. 60 , if the microcontroller detects a current draw that exceeds a predefined threshold value at step  3511 , the microcontroller can proceed to step  3513  and the firing element can be paused. For example, the microcontroller can pause movement and/or translation of the firing element for one second if the current increase measured by the microcontroller exceeds the threshold value. In other instances, the firing stroke can be paused for a fraction of a second and/or more than one second, for example. Similar to the process described above, if the current draw increase is less than the threshold value, the microcontroller can proceed to step  3515  and the firing element can continue to progress through the firing stroke without adjusting the velocity of the firing element. In certain instances, the microcontroller can be configured to pause and slow the firing element during a firing stroke. For example, for a first increase in current draw, the firing element can be paused, and for a second, different increase in current draw, the velocity of the firing element can be reduced. In still other circumstances, the microcontroller can command an increase in the velocity of the firing element if the current draw decreases below a threshold value, for example. 
     As described herein, a surgical instrument, such as a surgical stapling instrument, for example, can include a processor, computer, and/or controller, for example, (herein collectively referred to as a “processor”) and one or more sensors in signal communication with the processor, computer, and/or controller. In various instances, a processor can comprise a microcontroller and one or more memory units operationally coupled to the microcontroller. By executing instruction code stored in the memory, the processor may control various components of the surgical instrument, such as the motor, various drive systems, and/or a user display, for example. The processor may be implemented using integrated and/or discrete hardware elements, software elements, and/or a combination of both. Examples of integrated hardware elements may include processors, microprocessors, microcontrollers, integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate arrays (FPGA), logic gates, registers, semiconductor devices, chips, microchips, chip sets, microcontrollers, system-on-chip (SoC), and/or system-in-package (SIP). Examples of discrete hardware elements may include circuits and/or circuit elements such as logic gates, field effect transistors, bipolar transistors, resistors, capacitors, inductors, and/or relays. In certain instances, the processor may include a hybrid circuit comprising discrete and integrated circuit elements or components on one or more substrates, for example. 
     The processor may be an LM 4F230H5QR, available from Texas Instruments, for example. In certain instances, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available. Other microcontrollers may be readily substituted for use with the present disclosure. Accordingly, the present disclosure should not be limited in this context. 
     Signal communication can comprise any suitable form of communication in which information is transmitted between a sensor and the processor. Such communication can comprise wired communication utilizing one or more conductors and/or wireless communication utilizing a wireless transmitter and receiver, for example. In various instances, a surgical instrument can include a first sensor configured to detect a first condition of the surgical instrument and a second sensor configured to detect a second condition of the surgical instrument. For instance, the surgical instrument can include a first sensor configured to detect whether a closure trigger of the surgical instrument has been actuated and a second sensor configured to detect whether a firing trigger of the surgical instrument has been actuated, for example. 
     Various embodiments are envisioned in which the surgical instrument can include two or more sensors configured to detect the same condition. In at least one such embodiment, the surgical instrument can comprise a processor, a first sensor in signal communication with the processor, and a second sensor in signal communication with the processor. The first sensor can be configured to communicate a first signal to the processor and the second sensor can be configured to communicate a second signal to the processor. In various instances, the processor can include a first input channel for receiving the first signal from the first sensor and a second input channel for receiving the second signal from the second sensor. In other instances, a multiplexer device can receive the first signal and the second signal and communicate the data of the first and second signals to the processor as part of a single, combined signal, for example. In some instances, a first conductor, such as a first insulated wire, for example, can connect the first sensor to the first input channel and a second conductor, such as a second insulated wire, for example, can connect the second sensor to the second input channel. As outlined above, the first sensor and/or the second sensor can communicate wirelessly with the processor. In at least one such instance, the first sensor can include a first wireless transmitter and the second sensor can include a second wireless transmitter, wherein the processor can include and/or can be in communication with at least one wireless signal receiver configured to receive the first signal and/or the second signal and transmit the signals to the processor. 
     In co-operation with the sensors, as described in greater detail below, the processor of the surgical instrument can verify that the surgical instrument is operating correctly. The first signal can include data regarding a condition of the surgical instrument and the second signal can include data regarding the same condition. The processor can include an algorithm configured to compare the data from the first signal to the data from the second signal and determine whether the data communicated by the two signals are the same or different. If the data from the two signals are the same, the processor may use the data to operate the surgical instrument. In such circumstances, the processor can assume that a fault condition does not exist. In various instances, the processor can determine whether the data from the first signal and the data from the second signal are within an acceptable, or recognized, range of data. If the data from the two signals are within the recognized range of data, the processor may use the data from one or both of the signals to operate the surgical instrument. In such circumstances, the processor can assume that a fault condition does not exist. If the data from the first signal is outside of the recognized range of data, the processor may assume that a fault condition exists with regard to the first sensor, ignore the first signal, and operate the surgical instrument in response to the data from the second signal. Likewise, if the data from the second signal is outside the recognized range of data, the processor may assume that a fault condition exists with regard to the second sensor, ignore the second signal, and operate the surgical instrument in response to the data from the first signal. The processor can be configured to selectively ignore the input from one or more sensors. 
     In various instances, further to the above, the processor can include a module configured to implement an algorithm configured to assess whether the data from the first signal is between a first value and a second value. Similarly, the algorithm can be configured to assess whether the data from the second signal is between the first value and the second value. In certain instances, a surgical instrument can include at least one memory device. A memory device can be integral with the processor, in signal communication with the processor, and/or accessible by the processor. In certain instances, the memory device can include a memory chip including data stored thereon. The data stored on the memory chip can be in the form of a lookup table, for example, wherein the processor can access the lookup table to establish the acceptable, or recognized, range of data. In certain instances, the memory device can comprise nonvolatile memory, such as bit-masked read-only memory (ROM) or flash memory, for example. Nonvolatile memory (NVM) may comprise other types of memory including, for example, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or battery backed random-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM). 
     Further to the above, the first sensor and the second sensor can be redundant. The processor can be configured to compare the first signal from the first sensor to the second signal from the second sensor to determine what action, if any, to take. In addition to or in lieu of the above, the processor can be configured to compare the data from the first signal and/or the second signal to limits established by the algorithm and/or data stored within a memory device. In various circumstances, the processor can be configured to apply a gain to a signal it receives, such as the first signal and/or the second signal, for example. For instance, the processor can apply a first gain to the first signal and a second gain to the second signal. In certain instances, the first gain can be the same as the second gain. In other instances, the first gain and the second gain can be different. In some circumstances, the processor can be configured to calibrate the first gain and/or the second gain. In at least one such circumstance, the processor can modify a gain such that the amplified signal is within a desired, or acceptable, range. In various instances, the unmodified gain and/or the modified gain can be stored within a memory device which is integral to and/or accessible by the processor. In certain embodiments, the memory device can track the history of the gains applied to a signal. In any event, the processor can be configured to provide this calibration before, during, and/or after a surgical procedure. 
     In various embodiments, the first sensor can apply a first gain to the first signal and the second sensor can apply a second gain to the second signal. In certain embodiments, the processor can include one or more output channels and can communicate with the first and second sensors. For instance, the processor can include a first output channel in signal communication with the first sensor and a second output channel in signal communication with the second sensor. Further to the above, the processor can be configured to calibrate the first sensor and/or the second sensor. The processor can send a first calibration signal through said first output channel in order to modify a first gain that the first sensor is applying to the first signal. Similarly, the processor can send a second calibration signal through said second output channel in order to modify a second gain that the second sensor is applying to the second signal. 
     As discussed above, the processor can modify the operation of the surgical instrument in view of the data received from the first signal and/or the second signal. In some circumstances, the processor can ignore the signal from a redundant sensor that the processor deems to be faulty. In some circumstances, the processor can return the surgical instrument to a safe state and/or warn the user of the surgical instrument that one or both of the sensors may be faulty. In certain circumstances, the processor can disable the surgical instrument. In various circumstances, the processor can deactivate and/or modify certain functions of the surgical instrument when the processor detects that one or more of the sensors may be faulty. In at least one such circumstance, the processor may limit the operable controls to those controls which can permit the surgical instrument to be safely removed from the surgical site, for example, when the processor detects that one or more of the sensors may be faulty. In at least one circumstance, when the processor detects that one or more of the sensors may be faulty. In certain circumstances, the processor may limit the maximum speed, power, and/or torque that can be delivered by the motor of the surgical instrument, for example, when the processor detects that one or more of the sensors may be faulty. In various circumstances, the processor may enable a recalibration control which may allow the user of the surgical instrument to recalibrate the mal-performing or non-performing sensor, for example, when the processor detects that one or more of the sensors may be faulty. While various exemplary embodiments utilizing two sensors to detect the same condition are described herein, various other embodiments are envisioned which utilize more than two sensors. The principles applied to the two sensor system described herein can be adapted to systems including three or more sensors. 
     As discussed above, the first sensor and the second sensor can be configured to detect the same condition of the surgical instrument. For instance, the first sensor and the second sensor can be configured to detect whether an anvil of the surgical instrument is in an open condition, for example. In at least one such instance, the first sensor can detect the movement of a closure trigger into an actuated position and the second sensor can detect the movement of an anvil into a clamped position, for example. In some instances, the first sensor and the second sensor can be configured to detect the position of a firing member configured to deploy staples from an end effector of the surgical instrument. In at least one such instance, the first sensor can be configured to detect the position of a motor-driven rack in a handle of the surgical instrument and the second sensor can be configured to detect the position of a firing member in a shaft or an end effector of the surgical instrument which is operably coupled with the motor-driven rack, for example. In various instances, the first and second sensors could verify that the same event is occurring. The first and second sensors could be located in the same portion of the surgical instrument and/or in different portions of the surgical instrument. A first sensor can be located in the handle, for example, and a second sensor could be located in the shaft or the end effector, for example. 
     Further to the above, the first and second sensors can be utilized to determine whether two events are occurring at the same time. For example, whether the closure trigger and the anvil are moving, or have moved, concurrently. In certain instances, the first and second sensors can be utilized to determine whether two events are not occurring at the same time. For example, it may not be desirable for the anvil of the end effector to open while the firing member of the surgical instrument is being advanced to deploy the staples from the end effector. The first sensor can be configured to determine whether the anvil is in an clamped position and the second sensor can be configured to determine whether the firing member is being advanced. In the event that the first sensor detects that the anvil is in an unclamped position while the second sensor detects that the firing member is being advanced, the processor can interrupt the supply of power to the motor of the surgical instrument, for example. Similarly, the first sensor can be configured to detect whether an unclamping actuator configured to unclamp the end effector has been depressed and the second sensor can be configured to detect whether a firing actuator configured to operate the motor of the surgical instrument has been depressed. The processor of the surgical instrument can be configured to resolve these conflicting instructions by stopping the motor, reversing the motor to retract the firing member, and/or ignoring the instructions from the unclamping actuator, for example. 
     In some instances, further to the above, the condition detected can include the power consumed by the surgical instrument. In at least one such instance, the first sensor can be configured to monitor the current drawn from a battery of the surgical instrument and the second sensor can be configured to monitor the voltage of the battery. As discussed above, such information can be communicated from the first sensor and the second sensor to the processor. With this information, the processor can calculate the electrical power draw of the surgical instrument. Such a system could be referred to as ‘supply side’ power monitoring. In certain instances, the first sensor can be configured to detect the current drawn by a motor of the surgical instrument and the second sensor can be configured to detect the current drawn by a processor of the surgical instrument, for example. As discussed above, such information can be communicated from the first sensor and the second sensor to the processor. With this information, the processor can calculate the electrical power draw of the surgical instrument. To the extent that other components of the surgical instrument draw electrical power, a sensor could be utilized to detect the current drawn for each component and communicate that information to the processor. Such a system could be referred to as ‘use side’ power monitoring. Various embodiments are envisioned which utilize supply side power monitoring and use side power monitoring. In various instances, the processor, and/or an algorithm implemented by the processor, can be configured to calculate a state of the device using more than one sensor that may not be sensed directly by only one sensor. Based on this calculation, the processor can enable, block, and/or modify a function of the surgical instrument. 
     In various circumstances, the condition of the surgical instrument that can be detected by a processor and a sensor system can include the orientation of the surgical instrument. In at least one embodiment, the surgical instrument can include a handle, a shaft extending from the handle, and an end effector extending from the shaft. A first sensor can be positioned within the handle and a second sensor can be positioned within the shaft, for example. The first sensor can comprise a first tilt sensor and the second sensor can comprise a second tilt sensor, for example. The first tilt sensor can be configured to detect the instrument&#39;s orientation with respect to a first plane and the second tilt sensor can be configured to detect the instrument&#39;s orientation with respect to a second plane. The first plane and the second plane may or may not be orthogonal. The first sensor can comprise an accelerometer and/or a gyroscope, for example. The second sensor can comprise an accelerometer and/or a gyroscope, for example. Various embodiments are envisioned which comprise more than two sensors and each such sensor can comprise an accelerometer and/or a gyroscope, for example. In at least one implementation, a first sensor can comprise a first accelerometer arranged along a first axis and a second sensor can comprise a second accelerometer arranged along a second axis which is different than the first axis. In at least one such instance, the first axis can be transverse to the second axis. 
     Further to the above, the processor can utilize data from the first and second accelerometers to determine the direction in which gravity is acting with respect to the instrument, i.e., the direction of ground with respect to the surgical instrument. In certain instances, magnetic fields generated in the environment surrounding the surgical instrument may affect one of the accelerometers. Further to the above, the processor can be configured to ignore data from an accelerometer if the data from the accelerometers is inconsistent. Moreover, the processor can be configured to ignore data from an accelerometer if the accelerometer is dithering between two or more strong polarity orientations, for example. To the extent that an external magnetic field is affecting two or more, and/or all, of the accelerometers of a surgical instrument, the processor can deactivate certain functions of the surgical instrument which depend on data from the accelerometers. In various instances, a surgical instrument can include a screen configured to display images communicated to the screen by the processor, wherein the processor can be configured to change the orientation of the images displayed on the screen when the handle of the surgical instrument is reoriented, or at least when a reorientation of the handle is detected by the accelerometers. In at least one instance, the display on the screen can be flipped upside down when the handle is oriented upside down. In the event that the processor determines that orientation data from one or more of the accelerometers may be faulty, the processor may prevent the display from being reoriented away from its default position, for example. 
     Further to the above, the orientation of a surgical instrument may or may not be detectable from a single sensor. In at least one instance, the handle of the surgical instrument can include a first sensor and the shaft can include a second sensor, for example. Utilizing data from the first sensor and the second sensor, and/or data from any other sensor, the processor can determine the orientation of the surgical instrument. In some instances, the processor can utilize an algorithm configured to combine the data from the first sensor signal, the second sensor signal, and/or any suitable number of sensor signals to determine the orientation of the surgical instrument. In at least one instance, a handle sensor positioned within the handle can determine the orientation of the handle with respect to gravity. A shaft sensor positioned within the shaft can determine the orientation of the shaft with respect to gravity. In embodiments where the shaft, or at least a portion of the shaft, does not articulate relative to the handle, the processor can determine the direction in which the shaft, or the non-articulated shaft portion, is pointing. In some instances, a surgical instrument can include an end effector which can articulate relative to the shaft. The surgical instrument can include an articulation sensor which can determine the direction and the degree in which the end effector has been articulated relative to the shaft, for example. With data from the handle sensor, the shaft sensor, and the articulation sensor, the processor can determine the direction in which the end effector is pointing. With additional data including the length of the handle, the shaft, and/or the end effector, the processor can determine the position of the distal tip of the end effector, for example. With such information, the processor could enable, block, and/or modify a function of the surgical instrument. 
     In various instances, a surgical instrument can include a redundant processor in addition to a first processor. The redundant processor can be in signal communication with some or all of the sensors that the first processor is in signal communication with. The redundant processor can perform some or all of the same calculations that the first processor performs. The redundant processor can be in signal communication with the first processor. The first processor can be configured to compare the calculations that it has performed with the calculations that the redundant processor has performed. Similarly, the redundant processor can be configured to compare the calculations that it has performed with the calculations that the first processor has performed. In various instances, the first processor and the redundant processor can be configured to operate the surgical instrument independently of one another. In some instances, the first processor and/or the redundant processor can be configured to determine whether the other processor is faulty and/or deactivate the other processor if a fault within the other processor and/or within the surgical instrument is detected. The first processor and the redundant processor can both be configured to communicate with the operator of the surgical instrument such that, if one of the processors determines the other processor to be faulty, the non-faulty processor can communicate with the operator that a fault condition exists, for example. 
     In various embodiments, a surgical instrument can include a processor and one or more sensors in signal communication with the processor. The sensors can comprise digital sensors and/or analog sensors. A digital sensor can generate a measuring signal and can include an electronic chip. The electronic chip can convert the measuring signal into a digital output signal. The digital output signal can then be transmitted to the processor utilizing a suitable transmission means such as, for example, a conductive cable, a fiber optic cable, and/or a wireless emitter. An analog sensor can generate a measuring signal and communicate the measuring signal to the processor using an analog output signal. An analog sensor can include a Hall Effect sensor, a magnetoresistive sensor, an optical sensor, and/or any other suitable sensor, for example. A surgical instrument can include a signal filter which can be configured to receive and/or condition the analog output signal before the analog output signal reaches the processor. The signal filter can comprise a low-pass filter, for example, that passes signals to the processor having a low frequency which is at and/or below a cutoff frequency and that attenuates, or reduces the amplitude of, signals with high frequencies higher than the cutoff frequency. In some instances, the low-pass filter may eliminate certain high frequency signals that it receives or all of the high frequency signals that it receives. The low-pass filter may also attenuate, or reduce the amplitude of, certain or all of the low frequency signals, but such attenuation may be different than the attenuation that it applies to high frequency signals. Any suitable signal filter could be utilized. A high-pass filter, for example, could be utilized. A longpass filter could be utilized to receive and condition signals from optical sensors. In various instances, the processor can include an integral signal filter. In some instances, the processor can be in signal communication with the signal filter. In any event, the signal filter can be configured to reduce noise within the analog output signal, or signals, that it receives. 
     Further to the above, an analog output signal from a sensor can comprise a series of voltage potentials applied to an input channel of the processor. In various instances, the voltage potentials of the analog sensor output signal can be within a defined range. For instance, the voltage potentials can be between about 0V and about 12V, between about 0V and about 6V, between about 0V and about 3V, and/or between about 0V and about 1V, for example. In some instances, the voltage potentials can be less than or equal to 12V, less than or equal to 6V, less than or equal to 3V, and/or less than or equal to 1V, for example. In some instances, the voltage potentials can be between about 0V and about −12V, between about 0V and about −6V, between about 0V and about −3V, and/or between about 0V and about −1V, for example. In some instances, the voltage potentials can be greater than or equal to −12V, greater than or equal to −6V, greater than or equal to −3V, and/or greater than or equal to −1V, for example. In some instances, the voltage potentials can be between about 12V and about −12V, between about 6V and about −6V, between about 3V and about −3V, and/or between about 1V and about −1V, for example. In various instances, the sensor can supply voltage potentials to an input channel of the processor in a continuous stream. The processor may sample this stream of data at a rate which is less than rate in which data is delivered to the processor. In some instances, the sensor can supply voltage potentials to an input channel of the process intermittently or at periodic intervals. In any event, the processor can be configured to evaluate the voltage potentials applied to the input channel or channels thereof and operate the surgical instrument in response to the voltage potentials, as described in greater detail further below. 
     Further to the above, the processor can be configured to evaluate the analog output signal from a sensor. In various instances, the processor can be configured to evaluate every voltage potential of the analog output signal and/or sample the analog output signal. When sampling the analog output signal, the processor can make periodic evaluations of the signal to periodically obtain voltage potentials from the analog output signal. For each evaluation, the processor can compare the voltage potential obtained from the evaluation against a reference value. In various circumstances, the processor can calculate a digital value, such as 0 or 1, or on or off, for example, from this comparison. For instance, in the event that the evaluated voltage potential equals the reference value, the processor can calculate a digital value of 1. Alternatively, the processor can calculate a digital value of 0 if the evaluated voltage potential equals the reference value. With regard to a first embodiment, the processor can calculate a digital value of 1 if the evaluated voltage potential is less than the reference value and a digital value of 0 if the evaluated voltage potential is greater than the reference value. With regard to a second embodiment, the processor can calculate a digital value of 0 if the evaluated voltage potential is less than the reference value and a digital value of 1 if the evaluated voltage potential is greater than the reference value. In either event, the processor can convert the analog signal to a digital signal. When the processor is continuously evaluating the voltage potential of the sensor output signal, the processor can continuously compare the voltage potential to the reference value, and continuously calculate the digital value. When the processor is evaluating the voltage potential of the sensor output signal at periodic intervals, the processor can compare the voltage potential to the reference value at periodic intervals, and calculate the digital value at periodic intervals. 
     Further to the above, the reference value can be part of an algorithm utilized by the processor. The reference value can be pre-programmed in the algorithm. In some instances, the processor can obtain, calculate, and/or modify the reference value in the algorithm. In some instances, the reference value can be stored in a memory device which is accessible by and/or integral with the processor. The reference value can be pre-programmed in the memory device. In some instances, the processor can obtain, calculate, and/or modify the reference value in the memory device. In at least one instance, the reference value may be stored in non-volatile memory. In some instances, the reference value may be stored in volatile memory. The reference value may comprise a constant value. The reference value may or may not be changeable or overwritten. In certain instances, the reference value can be stored, changed, and/or otherwise determined as the result of a calibration procedure. The calibration procedure can be performed when manufacturing the surgical instrument, when initializing, or initially powering up, the instrument, when powering up the instrument from a sleep mode, when using the instrument, when placing the instrument into a sleep mode, and/or when completely powering down the instrument, for example. 
     Also further to the above, the processor can be configured to store the digital value. The digital value can be stored at an electronic logic gate. In various instances, the electronic logic gate can supply a binary output which can be referenced by the processor to assess a condition detected by the sensor, as described in greater detail further below. The processor can include the electronic logic gate. The binary output of the electronic logic gate can be updated. In various instances, the processor can include one or more output channels. The processor can supply the binary output to at least one of the output channels. The processor can apply a low voltage to such an output channel to indicate an off bit or a high voltage to the output channel to indicate an on bit, for example. The low voltage and the high voltage can be measured relative to a threshold value. In at least one instance, the low voltage can comprise no voltage, for example. In at least one other instance, the low voltage can comprise a voltage having a first polarity and the high voltage can comprise a voltage having an opposite polarity, for example. 
     In at least one instance, if the voltage potentials evaluated by the processor are consistently at or below the reference value, the electronic logic gate can maintain an output of ‘on’. When an evaluated voltage potential exceeds the reference value, the output of the logic gate can be switched to ‘off’. If the voltage potentials evaluated by the processor are consistently above the reference value, the electronic logic gate can maintain an output of ‘off’. When an evaluated voltage potential is thereafter measured at or below the reference value, the output of the logic gate can be switched back to ‘on’, and so forth. In various instances, the electronic logic gate may not maintain a history of its output. In some instances, the processor can include a memory device configured to record the output history of the electronic logic gate, i.e., record a history of the calculated digital value. In various instances, the processor can be configured to access the memory device to ascertain the current digital value and/or at least one previously-existing digital value, for example. 
     In various instances, the processor can provide an immediate response to a change in the calculated digital value. When the processor first detects that the calculated digital value has changed from ‘on’ to ‘off’ or from ‘off’ to ‘on’, for example, the processor can immediately modify the operation of the surgical instrument. In certain instances, the processor may not immediately modify the operation of the surgical instrument upon detecting that the calculated digital value has changed from ‘on’ to ‘off’ or from ‘off’ to ‘on’, for example. The processor may employ a hysteresis algorithm. For instance, the processor may not modify the operation of the surgical instrument until after the digital value has been calculated the same way a certain number of consecutive times. In at least one such instance, the processor may calculate an ‘on’ value and display an ‘on’ binary value at the output logic gate and/or the output channel based on the data it has received from one or more surgical instrument sensors wherein, at some point thereafter, the processor may calculate an ‘off’ value based on the data it has received from one or more of the surgical instrument sensors; however, the processor may not immediately display an ‘off’ binary value at the output logic gate and/or the output channel. Rather, the processor may delay changing the binary value at the output logic gate and/or the output channel until after the processor has calculated the ‘off’ value a certain number of consecutive times, such as ten times, for example. Once the processor has changed the binary value at the output logic gate and/or the output channel, the processor may likewise delay changing the binary value at the output logic gate and/or the output channel until after the processor has calculated the ‘on’ value a certain number of consecutive times, such as ten times, for example, and so forth. 
     A hysteresis algorithm may be suitable for handling switch debounce. A surgical instrument can include a switch debouncer circuit which utilizes a capacitor to filter out any quick changes of signal response. 
     In the example provided above, the sampling delay for going from ‘on’ to ‘off’ was the same as the sampling delay for going from ‘off’ to ‘on’. Embodiments are envisioned in which the sampling delays are not equal. For instance, if an ‘on’ value at an output channel activates the motor of the surgical instrument and an ‘off’ value at an output channel deactivates the motor, the ‘on’ delay may be longer than the ‘off’ delay, for example. In such instances, the processor may not suddenly activate the motor in response to accidental or incidental movements of the firing trigger while, on the other hand, the processor may react quickly to a release of the firing trigger to stop the motor. In at least one such instance, the processor may have an ‘on’ delay but no ‘off’ delay such that the motor can be stopped immediately after the firing trigger is released, for example. As discussed above, the processor may wait for a certain number of consecutive consistent binary output calculations before changing the binary output value. Other algorithms are contemplated. For instance, a processor may not require a certain number of consecutive consistent binary output calculations; rather, the processor may only require that a certain number, or percentage, of consecutive calculations be consistent in order to change the binary output. 
     As discussed above, a processor can convert an analog input signal to a digital output signal utilizing a reference value. As also discussed above, the processor can utilize the reference value to convert the analog input data, or samples of the analog input data, to ‘on’ values or ‘off’ values as part of its digital output signal. In various instances, a processor can utilize more than one reference value in order to determine whether to output an ‘on’ value or an ‘off’ value. One reference value can define two ranges. A range below the reference value and a range above the reference value. The reference value itself can be part of the first range or the second range, depending on the circumstances. The use of additional reference values can define additional ranges. For instance, a first reference value and a second reference value can define three ranges: a first range below the first reference value, a second range between the first reference value and the second reference value, and a third range above the second reference value. Again, the first reference value can be part of the first range or the second range and, similarly, the second reference value can be part of the second range or the third range, depending on the circumstances. For a given sample of data from an analog signal, the processor can determine whether the sample lies within the first range, the second range, or the third range. In at least one exemplary embodiment, the processor can assign an ‘on’ value to the binary output if the sample is in the first range and an ‘off’ value to the binary output if the sample is in the third range. Alternatively, the processor can assign an ‘off’ value to the binary output if the sample is in the first range and an ‘on’ value to the binary output if the sample is in the third range. 
     Further to the above, the processor can assign an ‘on’ value or an ‘off’ value to the binary output if the data sample is in the second range. In various instances, an analog data sample in the second range may not change the binary output value. For instance, if the processor has been receiving analog data above the second reference value and producing a certain binary output and, subsequently, the processor receives analog data between the first reference value and the second reference value, the processor may not change the binary output. If the processor, in this example, receives analog data below the first reference value, the processor may then change the binary output. Correspondingly, in this example, if the processor has been receiving analog data below the first reference value and producing a certain binary output and, subsequently, the processor receives analog data between the first reference value and the second reference value, the processor may not change the binary output. If the processor, in this example, receives analog data above the second reference value, the processor may then change the binary output. In various instances, the second range between the first reference value and the second reference value may comprise an observation window within which the processor may not change the binary output signal. In certain instances, the processor may utilize different sampling delays, depending on whether the analog input data jumps directly between the first range and the third range or whether the analog input data transitions into the second range before transitioning into the third range. For example, the sampling delay may be shorter if the analog input data transitions into the second range before transitioning into the first range or the third range as compared to when analog input data jumps directly between the first range and the third range. 
     As discussed above, an analog sensor, such as a Hall effect sensor, for example, can be utilized to detect a condition of a surgical instrument. In various instances, a Hall effect sensor can produce a linear analog output which can include a positive polarity and a negative polarity and, in certain instances, produce a wide range of analog output values. Such a wide range of values may not always be useful, or may not correspond to events which are actually possible for the surgical instrument. For instance, a Hall effect sensor can be utilized to track the orientation of the anvil of an end effector which, owing to certain physical constraints to the motion of the anvil, may only move through a small range of motion, such as about 30 degrees, for example. Although the Hall effect sensor could detect motion of the anvil outside this range of motion, as a practical matter, the Hall effect sensor will not need to and, as a result, a portion of the output range of the Hall effect sensor may not be utilized. The processor may be programmed to only recognize a range of output from the Hall effect sensor which corresponds to a possible range of motion of the anvil and, to the extent that the processor receives data from the Hall effect sensor which is outside of this range of output, whether above the range or below the range, the processor can ignore such data, generate a fault condition, modify the operation of the surgical instrument, and/or notify the user of the surgical instrument, for example. In such instances, the processor may recognize a valid range of data from the sensor and any data received from the sensor which is outside of this range may be deemed invalid by the processor. The valid range of data may be defined by a first reference value, or threshold, and a second reference value, or threshold. The valid range of data may include data having a positive polarity and a negative polarity. Alternatively, the valid range of data may only comprise data from the positive polarity or data from the negative polarity. 
     The first reference value and the second reference value, further to the above, can comprise fixed values. In certain circumstances, the first reference value and/or the second reference value can be calibrated. The first reference value and/or the second reference value can be calibrated when the surgical instrument is initially manufactured and/or subsequently re-manufactured. For instance, a trigger, such as the closure trigger, for example, can be moved through its entire range of motion during a calibration procedure and a Hall effect sensor, for example, positioned within the surgical instrument handle can detect the motion of the closure trigger, or at least the motion of a magnetic element, such as a permanent magnet, for example, positioned on the closure trigger. When the closure trigger is in its unclamped position, the reading taken by the Hall effect sensor can be stored as a first set point which corresponds with the unclamped position of the closure trigger. Similarly, when the closure trigger is in its fully clamped position, the reading taken by the Hall effect sensor can be stored as a second set point which corresponds with the fully clamped position of the closure trigger. Thereafter, the first set point can define the first reference value and the second set point can define the second reference value. Positions of the closure trigger between its unclamped position and its fully clamped position can correspond to the range of data between the first reference value and the second reference value. As outlined above, the processor can produce a digital output value in response to the data received from the analog sensor. In at least one instance, the processor can assign an ‘off’ value to its digital output when the data received from the analog sensor is at or above the first reference value. Alternatively, the processor can assign an ‘off’ value to its digital output when the data received from the analog sensor is above, at, or within about 20% of the range preceding first reference value, for example. Data from the analog sensor which is between the first reference value and about 20% of the range below the first reference value can correspond with a position of the closure trigger which is suitably close to is unclamped position. In at least one instance, the processor can assign an ‘on’ value to its digital output when the data received from the analog sensor is below the first reference value. Alternatively, the processor can assign an ‘on’ value to its digital output when the data received from the analog sensor is at, below, or within about 40% of the range above the second reference value can correspond with a position of the closure trigger when it has been pulled about ¾ through its range of motion, for example. The same or similar attributes could be applied to a firing trigger of the surgical instrument, for example. 
     Further to the above, a sensor can be calibrated in view of a reference value. For instance, if a reference value of +2V, for example, is associated with an unclamped position of the closure trigger and the processor detects a sensor output value which is different than +2V when the closure trigger is in its unclamped position, the processor can recalibrate the sensor, or the gain of the sensor, such that the sensor output matches, or at least substantially matches, the reference value. The processor may utilize an independent method of confirming that the closure trigger is in its unclamped position. In at least one such instance, the surgical instrument can include a second sensor in signal communication with the processor which can independently verify that the closure trigger is in its unclamped position. The second sensor could also comprise an analog sensor, such as a Hall effect sensor, for example. The second sensor could comprise a proximity sensor, a resistance based sensor, and/or any other suitable sensor, for example. The same or similar attributes could be applied to a firing trigger of the surgical instrument, for example. 
     As discussed above, referring to  FIGS. 14-18A , a tracking system  800  can comprise one or more sensors, such as a first Hall effect sensor  803  and a second Hall effect sensor  804 , for example, which can be configured to track the position of the magnet  802 . Upon comparing  FIGS. 14 and 17 , the reader will appreciate that, when the closure trigger  32  is moved from its unactuated position to its actuated position, the magnet  802  can move between a first position adjacent the first Hall effect sensor  803  and a second position adjacent the second Hall effect sensor  804 . When the magnet  802  is in its first position, the position of the magnet  802  can be detected by the first Hall effect sensor  803  and/or the second Hall effect sensor  804 . The processor of the surgical instrument can use data from the first sensor  803  to determine the position of the magnet  802  and data from the second sensor  804  to independently determine the position of the magnet  802 . In such instances, the processor can utilize data from the second sensor  804  to verify the integrity of the data from the first sensor  803 . Alternatively, the processor could utilize the data from the first sensor  803  to verify the integrity of the data from the second sensor  804 . The processor can utilize any suitable hierarchy for determining whether the data from a sensor should be used to provide a primary determination or a secondary determination of the position of the magnet  802 . For instance, when the magnet  802  is in its first position, the magnet  802  may provide a larger disturbance to the magnetic field surrounding the first sensor  803  than to the magnetic field surrounding the second sensor  804  and, as a result, the processor may utilize the data from the first sensor  803  as a primary determination of the position of the magnet  802 . When the magnet  802  is closer to the second sensor  804  than the first sensor  803 , the magnet  802  may provide a larger disturbance to the magnetic field surrounding the second sensor  804  than to the magnetic field surrounding the first sensor  803  and, as a result, the processor may utilize the data from the second sensor  804  as a primary determination of the position of the magnet  802 . 
     Further to the above, the path of the magnet  802  relative to the first sensor  803  can be determined when the magnet  802  moves along a first path segment when the closure trigger  32  is moved between its unclamped position and its clamped position and a second path segment when the firing trigger  130  is moved between its unfired position and its fired position. The range of outputs that the first sensor  803  will produce while tracking the magnet  802  as it moves along its first path segment can define a first valid range of data while the range of outputs that the first sensor  803  will produce while tracking the magnet  802  as it moves along its second path segment can define a second valid range of data. The first valid range of data may or may not be contiguous with the second valid range of data. In either event, the path of the magnet  802  relative to the second sensor  804  can also be determined when the magnet  802  moves along its first path segment and its second path segment. The range of outputs that the second sensor  804  will produce while tracking the magnet  802  as it moves along its first path segment can define a first valid range of data while the range of outputs that the second sensor  804  will produce while tracking the magnet  802  as it moves along its second path segment can define a second valid range of data. When the first sensor  803  and/or the second sensor  804  receives data outside of its respective first valid range of data and second valid range of data, the processor may assume that an error has occurred, modify the operation of the surgical instrument, and/or notify the operator of the surgical instrument. In certain instances, the processor can be configured to utilize data from the first sensor  803  and the second sensor  804  to determine whether the surgical instrument has been positioned within a strong external magnetic field which can affect the operation of the surgical instrument. For instance, the magnet  802  may move along a path such that the first sensor  803  and the second sensor  804  do not produce the same output at the same time and, in the event that first sensor  803  and the second sensor  804  produce the same output at the same time, the processor can determine that a fault condition exists, for example. 
       FIGS. 69-71B  generally depict a motor-driven surgical fastening and cutting instrument  2000 . As illustrated in  FIGS. 69 and 70 , the surgical instrument  2000  may include a handle assembly  2002 , a shaft assembly  2004 , and a power assembly  2006  (“power source,” “power pack,” or “battery pack”). The shaft assembly  2004  may include an end effector  2008  which, in certain circumstances, can be configured to act as an endocutter for clamping, severing, and/or stapling tissue, although, in other embodiments, different types of end effectors may be used, such as end effectors for other types of surgical devices, graspers, cutters, staplers, clip appliers, access devices, drug/gene therapy devices, ultrasound devices, RF device, and/or laser devices, for example. Several RF devices may be found in U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008, the entire disclosures of which are incorporated herein by reference in their entirety. 
     Referring primarily to  FIGS. 70, 71A, and 71B , the handle assembly  2002  can be employed with a plurality of interchangeable shaft assemblies such as, for example, the shaft assembly  2004 . Such interchangeable shaft assemblies may comprise surgical end effectors such as, for example, the end effector  2008  that can be configured to perform one or more surgical tasks or procedures. Examples of suitable interchangeable shaft assemblies are disclosed in U.S. Provisional Patent Application Ser. No. 61/782,866, entitled CONTROL SYSTEM OF A SURGICAL INSTRUMENT, and filed Mar. 14, 2013, the entire disclosure of which is hereby incorporated by reference herein in its entirety. 
     Referring primarily to  FIG. 70 , the handle assembly  2002  may comprise a housing  2010  that consists of a handle  2012  that may be configured to be grasped, manipulated and actuated by a clinician. However, it will be understood that the various unique and novel arrangements of the various forms of interchangeable shaft assemblies disclosed herein may also be effectively employed in connection with robotically-controlled surgical systems. Thus, the term “housing” may also encompass a housing or similar portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the interchangeable shaft assemblies disclosed herein and their respective equivalents. For example, the interchangeable shaft assemblies disclosed herein may be employed with various robotic systems, instruments, components and methods disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, which is incorporated by reference herein in its entirety. 
     Referring again to  FIG. 70 , the handle assembly  2002  may operably support a plurality of drive systems therein that can be configured to generate and apply various control motions to corresponding portions of the interchangeable shaft assembly that is operably attached thereto. For example, the handle assembly  2002  can operably support a first or closure drive system, which may be employed to apply closing and opening motions to the shaft assembly  2004  while operably attached or coupled to the handle assembly  2002 . In at least one form, the handle assembly  2002  may operably support a firing drive system that can be configured to apply firing motions to corresponding portions of the interchangeable shaft assembly attached thereto. 
     Referring primarily to  FIGS. 71A and 71B , the handle assembly  2002  may include a motor  2014  which can be controlled by a motor driver  2015  and can be employed by the firing system of the surgical instrument  2000 . In various forms, the motor  2014  may be a DC brushed driving motor having a maximum rotation of, approximately, 25,000 RPM, for example. In other arrangements, the motor  2014  may include a brushless motor, a cordless motor, a synchronous motor, a stepper motor, or any other suitable electric motor. In certain circumstances, the motor driver  2015  may comprise an H-Bridge field-effect transistors (FETs)  2019 , as illustrated in  FIGS. 71A and 71B , for example. The motor  2014  can be powered by the power assembly  2006  ( FIGS. 71A and 71B ) which can be releasably mounted to the handle assembly  2002  for supplying control power to the surgical instrument  2000 . The power assembly  2006  may comprise a battery which may include a number of battery cells connected in series that can be used as the power source to power the surgical instrument  2000 . In certain circumstances, the battery cells of the power assembly  2006  may be replaceable and/or rechargeable. In at least one example, the battery cells can be Lithium-Ion batteries which can be separably couplable to the power assembly  2006 . 
     The shaft assembly  2004  may include a shaft assembly controller  2022  which can communicate with the power management controller  2016  through an interface while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . For example, the interface may comprise a first interface portion  2025  which may include one or more electric connectors for coupling engagement with corresponding shaft assembly electric connectors and a second interface portion  2027  which may include one or more electric connectors for coupling engagement with corresponding power assembly electric connectors to permit electrical communication between the shaft assembly controller  2022  and the power management controller  2016  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . One or more communication signals can be transmitted through the interface to communicate one or more of the power requirements of the attached interchangeable shaft assembly  2004  to the power management controller  2016 . In response, the power management controller may modulate the power output of the battery of the power assembly  2006 , as described below in greater detail, in accordance with the power requirements of the attached shaft assembly  2004 . In certain circumstances, one or more of the electric connectors may comprise switches which can be activated after mechanical coupling engagement of the handle assembly  2002  to the shaft assembly  2004  and/or to the power assembly  2006  to allow electrical communication between the shaft assembly controller  2022  and the power management controller  2016 . 
     In certain circumstances, the interface can facilitate transmission of the one or more communication signals between the power management controller  2016  and the shaft assembly controller  2022  by routing such communication signals through a main controller  2017  residing in the handle assembly  2002 , for example. In other circumstances, the interface can facilitate a direct line of communication between the power management controller  2016  and the shaft assembly controller  2022  through the handle assembly  2002  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . 
     In one instance, the main microcontroller  2017  may be any single core or multicore processor such as those known under the trade name ARM Cortex by Texas Instruments. In one instance, the surgical instrument  2000  may comprise a power management controller  2016  such as, for example, a safety microcontroller platform comprising two microcontroller-based families such as TMS570 and RM4x known under the trade name Hercules ARM Cortex R4, also by Texas Instruments. Nevertheless, other suitable substitutes for microcontrollers and safety processor may be employed, without limitation. In one instance, the safety processor may be configured specifically for IEC 61508 and ISO 26262 safety critical applications, among others, to provide advanced integrated safety features while delivering scalable performance, connectivity, and memory options. 
     In certain instances, the microcontroller  2017  may be an LM 4F230H5QR, available from Texas Instruments, for example. In at least one example, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available for the product datasheet. The present disclosure should not be limited in this context. 
     The power assembly  2006  may include a power management circuit which may comprise the power management controller  2016 , a power modulator  2038 , and a current sense circuit  2036 . The power management circuit can be configured to modulate power output of the battery based on the power requirements of the shaft assembly  2004  while the shaft assembly  2004  and the power assembly  2006  are coupled to the handle assembly  2002 . For example, the power management controller  2016  can be programmed to control the power modulator  2038  of the power output of the power assembly  2006  and the current sense circuit  2036  can be employed to monitor power output of the power assembly  2006  to provide feedback to the power management controller  2016  about the power output of the battery so that the power management controller  2016  may adjust the power output of the power assembly  2006  to maintain a desired output. 
     It is noteworthy that the power management controller  2016  and/or the shaft assembly controller  2022  each may comprise one or more processors and/or memory units which may store a number of software modules. Although certain modules and/or blocks of the surgical instrument  2000  may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used. Further, although various instances may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, Digital Signal Processors (DSPs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components. 
     In certain instances, the surgical instrument  2000  may comprise an output device  2042  which may include one or more devices for providing a sensory feedback to a user. Such devices may comprise, for example, visual feedback devices (e.g., an LCD display screen, LED indicators), audio feedback devices (e.g., a speaker, a buzzer) or tactile feedback devices (e.g., haptic actuators). In certain circumstances, the output device  2042  may comprise a display  2043  which may be included in the handle assembly  2002 . The shaft assembly controller  2022  and/or the power management controller  2016  can provide feedback to a user of the surgical instrument  2000  through the output device  2042 . The interface  2024  can be configured to connect the shaft assembly controller  2022  and/or the power management controller  2016  to the output device  2042 . The reader will appreciate that the output device  2042  can instead be integrated with the power assembly  2006 . In such circumstances, communication between the output device  2042  and the shaft assembly controller  2022  may be accomplished through the interface  2024  while the shaft assembly  2004  is coupled to the handle assembly  2002 . 
     Having described a surgical instrument  2000  in general terms, the description now turns to a detailed description of various electrical/electronic component of the surgical instrument  2000 . For expedience, any references hereinbelow to the surgical instrument  2000  should be construed to refer to the surgical instrument  2000  shown in connection with  FIGS. 69-71B . Turning now to  FIGS. 72A and 72B , where one embodiment of a segmented circuit  11000  comprising a plurality of circuit segments  11002   a - 11002   g  is illustrated. The segmented circuit  11000  comprising the plurality of circuit segments  11002   a - 11002   g  is configured to control a powered surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 69-71B , without limitation. The plurality of circuit segments  11002   a - 11002   g  is configured to control one or more operations of the powered surgical instrument  2000 . A safety processor segment  11002   a  (Segment 1) comprises a safety processor  11004 . A primary processor segment  11002   b  (Segment 2) comprises a primary processor  11006 . The safety processor  11004  and/or the primary processor  11006  are configured to interact with one or more additional circuit segments  11002   c - 11002   g  to control operation of the powered surgical instrument  2000 . The primary processor  11006  comprises a plurality of inputs coupled to, for example, one or more circuit segments  11002   c - 11002   g , a battery  11008 , and/or a plurality of switches  11058   a - 11070 . The segmented circuit  11000  may be implemented by any suitable circuit, such as, for example, a printed circuit board assembly (PCBA) within the powered surgical instrument  2000 . It should be understood that the term processor as used herein includes any microprocessor, microcontroller, or other basic computing device that incorporates the functions of a computer&#39;s central processing unit (CPU) on an integrated circuit or at most a few integrated circuits. The processor is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Processors operate on numbers and symbols represented in the binary numeral system. 
     In one embodiment, the main processor  11006  may be any single core or multicore processor such as those known under the trade name ARM Cortex by Texas Instruments. In one embodiment, the safety processor  11004  may be a safety microcontroller platform comprising two microcontroller-based families such as TMS570 and RM4x known under the trade name Hercules ARM Cortex R4, also by Texas Instruments. Nevertheless, other suitable substitutes for microcontrollers and safety processor may be employed, without limitation. In one embodiment, the safety processor  11004  may be configured specifically for IEC 61508 and ISO 26262 safety critical applications, among others, to provide advanced integrated safety features while delivering scalable performance, connectivity, and memory options. 
     In certain instances, the main processor  11006  may be an LM 4F230H5QR, available from Texas Instruments, for example. In at least one example, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available for the product datasheet. Other processors may be readily substituted and, accordingly, the present disclosure should not be limited in this context. 
     In one embodiment, the segmented circuit  11000  comprises an acceleration segment  11002   c  (Segment 3). The acceleration segment  11002   c  comprises an acceleration sensor  11022 . The acceleration sensor  11022  may comprise, for example, an accelerometer. The acceleration sensor  11022  is configured to detect movement or acceleration of the powered surgical instrument  2000 . In some embodiments, input from the acceleration sensor  11022  is used, for example, to transition to and from a sleep mode, identify an orientation of the powered surgical instrument, and/or identify when the surgical instrument has been dropped. In some embodiments, the acceleration segment  11002   c  is coupled to the safety processor  11004  and/or the primary processor  11006 . 
     In one embodiment, the segmented circuit  11000  comprises a display segment  11002   d  (Segment 4). The display segment  11002   d  comprises a display connector  11024  coupled to the primary processor  11006 . The display connector  11024  couples the primary processor  11006  to a display  11028  through one or more display driver integrated circuits  11026 . The display driver integrated circuits  11026  may be integrated with the display  11028  and/or may be located separately from the display  11028 . The display  11028  may comprise any suitable display, such as, for example, an organic light-emitting diode (OLED) display, a liquid-crystal display (LCD), and/or any other suitable display. In some embodiments, the display segment  11002   d  is coupled to the safety processor  11004 . 
     In some embodiments, the segmented circuit  11000  comprises a shaft segment  11002   e  (Segment 5). The shaft segment  11002   e  comprises one or more controls for a shaft  2004  coupled to the surgical instrument  2000  and/or one or more controls for an end effector  2006  coupled to the shaft  2004 . The shaft segment  11002   e  comprises a shaft connector  11030  configured to couple the primary processor  11006  to a shaft PCBA  11031 . The shaft PCBA  11031  comprises a first articulation switch  11036 , a second articulation switch  11032 , and a shaft PCBA electrically erasable programmable read-only memory (EEPROM)  11034 . In some embodiments, the shaft PCBA EEPROM  11034  comprises one or more parameters, routines, and/or programs specific to the shaft  2004  and/or the shaft PCBA  11031 . The shaft PCBA  11031  may be coupled to the shaft  2004  and/or integral with the surgical instrument  2000 . In some embodiments, the shaft segment  11002   e  comprises a second shaft EEPROM  11038 . The second shaft EEPROM  11038  comprises a plurality of algorithms, routines, parameters, and/or other data corresponding to one or more shafts  2004  and/or end effectors  2006  which may be interfaced with the powered surgical instrument  2000 . 
     In some embodiments, the segmented circuit  11000  comprises a position encoder segment  11002   f  (Segment 6). The position encoder segment  11002   f  comprises one or more magnetic rotary position encoders  11040   a - 11040   b . The one or more magnetic rotary position encoders  11040   a - 11040   b  are configured to identify the rotational position of a motor  11048 , a shaft  2004 , and/or an end effector  2006  of the surgical instrument  2000 . In some embodiments, the magnetic rotary position encoders  11040   a - 11040   b  may be coupled to the safety processor  11004  and/or the primary processor  11006 . 
     In some embodiments, the segmented circuit  11000  comprises a motor segment  11002   g  (Segment 7). The motor segment  11002   g  comprises a motor  11048  configured to control one or more movements of the powered surgical instrument  2000 . The motor  11048  is coupled to the primary processor  11006  by an H-Bridge driver  11042  and one or more H-bridge field-effect transistors (FETs)  11044 . The H-bridge FETs  11044  are coupled to the safety processor  11004 . A motor current sensor  11046  is coupled in series with the motor  11048  to measure the current draw of the motor  11048 . The motor current sensor  11046  is in signal communication with the primary processor  11006  and/or the safety processor  11004 . In some embodiments, the motor  11048  is coupled to a motor electromagnetic interference (EMI) filter  11050 . 
     The segmented circuit  11000  comprises a power segment  11002   h  (Segment 8). A battery  11008  is coupled to the safety processor  11004 , the primary processor  11006 , and one or more of the additional circuit segments  11002   c - 11002   g . The battery  11008  is coupled to the segmented circuit  11000  by a battery connector  11010  and a current sensor  11012 . The current sensor  11012  is configured to measure the total current draw of the segmented circuit  11000 . In some embodiments, one or more voltage converters  11014   a ,  11014   b ,  11016  are configured to provide predetermined voltage values to one or more circuit segments  11002   a - 11002   g . For example, in some embodiments, the segmented circuit  11000  may comprise 3.3V voltage converters  11014   a - 11014   b  and/or 5V voltage converters  11016 . A boost converter  11018  is configured to provide a boost voltage up to a predetermined amount, such as, for example, up to 13V. The boost converter  11018  is configured to provide additional voltage and/or current during power intensive operations and prevent brownout or low-power conditions. 
     In some embodiments, the safety segment  11002   a  comprises a motor power interrupt  11020 . The motor power interrupt  11020  is coupled between the power segment  11002   h  and the motor segment  11002   g . The safety segment  11002   a  is configured to interrupt power to the motor segment  11002   g  when an error or fault condition is detected by the safety processor  11004  and/or the primary processor  11006  as discussed in more detail herein. Although the circuit segments  11002   a - 11002   g  are illustrated with all components of the circuit segments  11002   a - 11002   h  located in physical proximity, one skilled in the art will recognize that a circuit segment  11002   a - 11002   h  may comprise components physically and/or electrically separate from other components of the same circuit segment  11002   a - 11002   g . In some embodiments, one or more components may be shared between two or more circuit segments  11002   a - 11002   g.    
     In some embodiments, a plurality of switches  11056 - 11070  are coupled to the safety processor  11004  and/or the primary processor  11006 . The plurality of switches  11056 - 11070  may be configured to control one or more operations of the surgical instrument  2000 , control one or more operations of the segmented circuit  11100 , and/or indicate a status of the surgical instrument  2000 . For example, a bail-out door switch  11056  is configured to indicate the status of a bail-out door. A plurality of articulation switches, such as, for example, a left side articulation left switch  11058   a , a left side articulation right switch  11060   a , a left side articulation center switch  11062   a , a right side articulation left switch  11058   b , a right side articulation right switch  11060   b , and a right side articulation center switch  11062   b  are configured to control articulation of a shaft  2004  and/or an end effector  2006 . A left side reverse switch  11064   a  and a right side reverse switch  11064   b  are coupled to the primary processor  11006 . In some embodiments, the left side switches comprising the left side articulation left switch  11058   a , the left side articulation right switch  11060   a , the left side articulation center switch  11062   a , and the left side reverse switch  11064   a  are coupled to the primary processor  11006  by a left flex connector  11072   a . The right side switches comprising the right side articulation left switch  11058   b , the right side articulation right switch  11060   b , the right side articulation center switch  11062   b , and the right side reverse switch  11064   b  are coupled to the primary processor  11006  by a right flex connector  11072   b . In some embodiments, a firing switch  11066 , a clamp release switch  11068 , and a shaft engaged switch  11070  are coupled to the primary processor  11006 . 
     The plurality of switches  11056 - 11070  may comprise, for example, a plurality of handle controls mounted to a handle of the surgical instrument  2000 , a plurality of indicator switches, and/or any combination thereof. In various embodiments, the plurality of switches  11056 - 11070  allow a surgeon to manipulate the surgical instrument, provide feedback to the segmented circuit  11000  regarding the position and/or operation of the surgical instrument, and/or indicate unsafe operation of the surgical instrument  2000 . In some embodiments, additional or fewer switches may be coupled to the segmented circuit  11000 , one or more of the switches  11056 - 11070  may be combined into a single switch, and/or expanded to multiple switches. For example, in one embodiment, one or more of the left side and/or right side articulation switches  11058   a - 11064   b  may be combined into a single multi-position switch. 
       FIGS. 73A and 73B  illustrate a segmented circuit  11100  comprising one embodiment of a safety processor  11104  configured to implement a watchdog function, among other safety operations. The safety processor  11004  and the primary processor  11106  of the segmented circuit  11100  are in signal communication. A plurality of circuit segments  11102   c - 11102   h  are coupled to the primary processor  11106  and are configured to control one or more operations of a surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 1-3 . For example, in the illustrated embodiment, the segmented circuit  11100  comprises an acceleration segment  11102   c , a display segment  11102   d , a shaft segment  11102   e , an encoder segment  11102   f , a motor segment  11102   g , and a power segment  11102   h . Each of the circuit segments  11102   c - 11102   g  may be coupled to the safety processor  11104  and/or the primary processor  11106 . The primary processor is also coupled to a flash memory  11186 . A microprocessor alive heartbeat signal is provided at output  11196 . 
     The acceleration segment  11102   c  comprises an accelerometer  11122  configured to monitor movement of the surgical instrument  2000 . In various embodiments, the accelerometer  11122  may be a single, double, or triple axis accelerometer. The accelerometer  11122  may be employed to measures proper acceleration that is not necessarily the coordinate acceleration (rate of change of velocity). Instead, the accelerometer sees the acceleration associated with the phenomenon of weight experienced by a test mass at rest in the frame of reference of the accelerometer  11122 . For example, the accelerometer  11122  at rest on the surface of the earth will measure an acceleration g=9.8 m/s 2  (gravity) straight upwards, due to its weight. Another type of acceleration that accelerometer  11122  can measure is g-force acceleration. In various other embodiments, the accelerometer  11122  may comprise a single, double, or triple axis accelerometer. Further, the acceleration segment  11102   c  may comprise one or more inertial sensors to detect and measure acceleration, tilt, shock, vibration, rotation, and multiple degrees-of-freedom (DoF). A suitable inertial sensor may comprise an accelerometer (single, double, or triple axis), a magnetometer to measure a magnetic field in space such as the earth&#39;s magnetic field, and/or a gyroscope to measure angular velocity. 
     The display segment  11102   d  comprises a display embedded in the surgical instrument  2000 , such as, for example, an OLED display. In certain embodiments, the surgical instrument  2000  may comprise an output device which may include one or more devices for providing a sensory feedback to a user. Such devices may comprise, for example, visual feedback devices (e.g., an LCD display screen, LED indicators), audio feedback devices (e.g., a speaker, a buzzer) or tactile feedback devices (e.g., haptic actuators). In some aspects, the output device may comprise a display which may be included in the handle assembly  2002 , as illustrated in  FIG. 69 . The shaft assembly controller and/or the power management controller can provide feedback to a user of the surgical instrument  2000  through the output device. An interface can be configured to connect the shaft assembly controller and/or the power management controller to the output device. 
     The shaft segment  11102   e  comprises a shaft circuit board  11131 , such as, for example, a shaft PCB, configured to control one or more operations of a shaft  2004  and/or an end effector  2006  coupled to the shaft  2004  and a Hall effect switch  1170  to indicate shaft engagement. The shaft circuit board  1131  also includes a low-power microprocessor  1190  with ferroelectric random access memory (FRAM) technology, a mechanical articulation switch  1192 , a shaft release Hall Effect switch  1194 , and flash memory  1134 . The encoder segment  11102   f  comprises a plurality of motor encoders  11140   a ,  11140   b  configured to provide rotational position information of a motor  11048 , the shaft  2004 , and/or the end effector  2006 . 
     The motor segment  11102   g  comprises a motor  11048 , such as, for example, a brushed DC motor. The motor  11048  is coupled to the primary processor  11106  through a plurality of H-bridge drivers  11142  and a motor controller  11143 . The motor controller  11143  controls a first motor flag  11174   a  and a second motor flag  11174   b  to indicate the status and position of the motor  11048  to the primary processor  11106 . The primary processor  11106  provides a pulse-width modulation (PWM) high signal  11176   a , a PWM low signal  11176   b , a direction signal  11178 , a synchronize signal  11180 , and a motor reset signal  11182  to the motor controller  11143  through a buffer  11184 . The power segment  11102   h  is configured to provide a segment voltage to each of the circuit segments  11102   a - 11102   g.    
     In one embodiment, the safety processor  11104  is configured to implement a watchdog function with respect to one or more circuit segments  11102   c - 11102   h , such as, for example, the motor segment  11102   g . In this regards, the safety processor  11104  employs the watchdog function to detect and recover from malfunctions of the primary processor  10006 . During normal operation, the safety processor  11104  monitors for hardware faults or program errors of the primary processor  11104  and to initiate corrective action or actions. The corrective actions may include placing the primary processor  10006  in a safe state and restoring normal system operation. In one embodiment, the safety processor  11104  is coupled to at least a first sensor. The first sensor measures a first property of the surgical instrument  2000 . In some embodiments, the safety processor  11104  is configured to compare the measured property of the surgical instrument  2000  to a predetermined value. For example, in one embodiment, a motor sensor  11140   a  is coupled to the safety processor  11104 . The motor sensor  11140   a  provides motor speed and position information to the safety processor  11104 . The safety processor  11104  monitors the motor sensor  11140   a  and compares the value to a maximum speed and/or position value and prevents operation of the motor  11048  above the predetermined values. In some embodiments, the predetermined values are calculated based on real-time speed and/or position of the motor  11048 , calculated from values supplied by a second motor sensor  11140   b  in communication with the primary processor  11106 , and/or provided to the safety processor  11104  from, for example, a memory module coupled to the safety processor  11104 . 
     In some embodiments, a second sensor is coupled to the primary processor  11106 . The second sensor is configured to measure the first physical property. The safety processor  11104  and the primary processor  11106  are configured to provide a signal indicative of the value of the first sensor and the second sensor respectively. When either the safety processor  11104  or the primary processor  11106  indicates a value outside of an acceptable range, the segmented circuit  11100  prevents operation of at least one of the circuit segments  11102   c - 11102   h , such as, for example, the motor segment  11102   g . For example, in the embodiment illustrated in  FIGS. 73A and 73B , the safety processor  11104  is coupled to a first motor position sensor  11140   a  and the primary processor  11106  is coupled to a second motor position sensor  11140   b . The motor position sensors  11140   a ,  11140   b  may comprise any suitable motor position sensor, such as, for example, a magnetic angle rotary input comprising a sine and cosine output. The motor position sensors  11140   a ,  11140   b  provide respective signals to the safety processor  11104  and the primary processor  11106  indicative of the position of the motor  11048 . 
     The safety processor  11104  and the primary processor  11106  generate an activation signal when the values of the first motor sensor  11140   a  and the second motor sensor  11140   b  are within a predetermined range. When either the primary processor  11106  or the safety processor  11104  to detect a value outside of the predetermined range, the activation signal is terminated and operation of at least one circuit segment  11102   c - 11102   h , such as, for example, the motor segment  11102   g , is interrupted and/or prevented. For example, in some embodiments, the activation signal from the primary processor  11106  and the activation signal from the safety processor  11104  are coupled to an AND gate. The AND gate is coupled to a motor power switch  11120 . The AND gate maintains the motor power switch  11120  in a closed, or on, position when the activation signal from both the safety processor  11104  and the primary processor  11106  are high, indicating a value of the motor sensors  11140   a ,  11140   b  within the predetermined range. When either of the motor sensors  11140   a ,  11140   b  detect a value outside of the predetermined range, the activation signal from that motor sensor  11140   a ,  11140   b  is set low, and the output of the AND gate is set low, opening the motor power switch  11120 . In some embodiments, the value of the first sensor  11140   a  and the second sensor  11140   b  is compared, for example, by the safety processor  11104  and/or the primary processor  11106 . When the values of the first sensor and the second sensor are different, the safety processor  11104  and/or the primary processor  11106  may prevent operation of the motor segment  11102   g.    
     In some embodiments, the safety processor  11104  receives a signal indicative of the value of the second sensor  11140   b  and compares the second sensor value to the first sensor value. For example, in one embodiment, the safety processor  11104  is coupled directly to a first motor sensor  11140   a . A second motor sensor  11140   b  is coupled to a primary processor  11106 , which provides the second motor sensor  11140   b  value to the safety processor  11104 , and/or coupled directly to the safety processor  11104 . The safety processor  11104  compares the value of the first motor sensor  11140  to the value of the second motor sensor  11140   b . When the safety processor  11104  detects a mismatch between the first motor sensor  11140   a  and the second motor sensor  11140   b , the safety processor  11104  may interrupt operation of the motor segment  11102   g , for example, by cutting power to the motor segment  11102   g.    
     In some embodiments, the safety processor  11104  and/or the primary processor  11106  is coupled to a first sensor  11140   a  configured to measure a first property of a surgical instrument and a second sensor  11140   b  configured to measure a second property of the surgical instrument. The first property and the second property comprise a predetermined relationship when the surgical instrument is operating normally. The safety processor  11104  monitors the first property and the second property. When a value of the first property and/or the second property inconsistent with the predetermined relationship is detected, a fault occurs. When a fault occurs, the safety processor  11104  takes at least one action, such as, for example, preventing operation of at least one of the circuit segments, executing a predetermined operation, and/or resetting the primary processor  11106 . For example, the safety processor  11104  may open the motor power switch  11120  to cut power to the motor circuit segment  11102   g  when a fault is detected. 
       FIG. 74  illustrates a block diagram of one embodiment of a segmented circuit  11200  comprising a safety processor  11204  configured to monitor and compare a first property and a second property of a surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 1-3 . The safety processor  11204  is coupled to a first sensor  11246  and a second sensor  11266 . The first sensor  11246  is configured to monitor a first physical property of the surgical instrument  2000 . The second sensor  11266  is configured to monitor a second physical property of the surgical instrument  2000 . The first and second properties comprise a predetermined relationship when the surgical instrument  2000  is operating normally. For example, in one embodiment, the first sensor  11246  comprises a motor current sensor configured to monitor the current draw of a motor from a power source. The motor current draw may be indicative of the speed of the motor. The second sensor comprises a linear hall sensor configured to monitor the position of a cutting member within an end effector, for example, an end effector  2006  coupled to the surgical instrument  2000 . The position of the cutting member is used to calculate a cutting member speed within the end effector  2006 . The cutting member speed has a predetermined relationship with the speed of the motor when the surgical instrument  2000  is operating normally. 
     The safety processor  11204  provides a signal to the main processor  11206  indicating that the first sensor  11246  and the second sensor  11266  are producing values consistent with the predetermined relationship. When the safety processor  11204  detects a value of the first sensor  11246  and/or the second sensor  11266  inconsistent with the predetermined relationship, the safety processor  11206  indicates an unsafe condition to the primary processor  11206 . The primary processor  11206  interrupts and/or prevents operation of at least one circuit segment. In some embodiments, the safety processor  11204  is coupled directly to a switch configured to control operation of one or more circuit segments. For example, with reference to  FIGS. 73A and 73B , in one embodiment, the safety processor  11104  is coupled directly to a motor power switch  11120 . The safety processor  11104  opens the motor power switch  11120  to prevent operation of the motor segment  11102   g  when a fault is detected. 
     Referring back to  FIGS. 73A and 73B , in one embodiment, the safety processor  11104  is configured to execute an independent control algorithm. In operation, the safety processor  11104  monitors the segmented circuit  11100  and is configured to control and/or override signals from other circuit components, such as, for example, the primary processor  11106 , independently. The safety processor  11104  may execute a preprogrammed algorithm and/or may be updated or programmed on the fly during operation based on one or more actions and/or positions of the surgical instrument  2000 . For example, in one embodiment, the safety processor  11104  is reprogrammed with new parameters and/or safety algorithms each time a new shaft and/or end effector is coupled to the surgical instrument  2000 . In some embodiments, one or more safety values stored by the safety processor  11104  are duplicated by the primary processor  11106 . Two-way error detection is performed to ensure values and/or parameters stored by either of the processors  11104 ,  11106  are correct. 
     In some embodiments, the safety processor  11104  and the primary processor  11106  implement a redundant safety check. The safety processor  11104  and the primary processor  11106  provide periodic signals indicating normal operation. For example, during operation, the safety processor  11104  may indicate to the primary processor  11106  that the safety processor  11104  is executing code and operating normally. The primary processor  11106  may, likewise, indicate to the safety processor  11104  that the primary processor  11106  is executing code and operating normally. In some embodiments, communication between the safety processor  11104  and the primary processor  11106  occurs at a predetermined interval. The predetermined interval may be constant or may be variable based on the circuit state and/or operation of the surgical instrument  2000 . 
       FIG. 75  is a block diagram illustrating a safety process  11250  configured to be implemented by a safety processor, such as, for example, the safety process  11104  illustrated in  FIGS. 73A and 73B . In one embodiment, values corresponding to a plurality of properties of a surgical instrument  2000  are provided to the safety processor  11104 . The plurality of properties is monitored by a plurality of independent sensors and/or systems. For example, in the illustrated embodiment, a measured cutting member speed  11252 , a propositional motor speed  11254 , and an intended direction of motor signal  11256  are provided to a safety processor  11104 . The cutting member speed  11252  and the propositional motor speed  11254  may be provided by independent sensors, such as, for example, a linear hall sensor and a current sensor respectively. The intended direction of motor signal  11256  may be provided by a primary processor, for example, the primary processor  11106  illustrated in  FIGS. 73A and 73B . The safety processor  11104  compares  11258  the plurality of properties and determines when the properties are consistent with a predetermined relationship. When the plurality of properties comprises values consistent with the predetermined relationship  11260   a , no action is taken  11262 . When the plurality of properties comprises values inconsistent with the predetermined relationship  11260   b , the safety processor  11104  executes one or more actions, such as, for example, blocking a function, executing a function, and/or resetting a processor. For example, in the process  11250  illustrated in  FIG. 75 , the safety processor  11104  interrupts operation of one or more circuit segments, such as, for example, by interrupting power  11264  to a motor segment. 
     Referring back to  FIGS. 73A and 73B , the segmented circuit  11100  comprises a plurality of switches  11156 - 11170  configured to control one or more operations of the surgical instrument  2000 . For example, in the illustrated embodiment, the segmented circuit  11100  comprises a clamp release switch  11168 , a firing trigger  11166 , and a plurality of switches  11158   a - 11164   b  configured to control articulation of a shaft  2004  and/or end effector  2006  coupled to the surgical instrument  2000 . The clamp release switch  11168 , the fire trigger  11166 , and the plurality of articulation switches  11158   a - 11164   b  may comprise analog and/or digital switches. In particular, switch  11156  indicates the mechanical switch lifter down position, switches  11158   a ,  11158   b  indicate articulate left (1) and (2), switch  11160   a ,  1160   b  indicate articulate right (1) and (2), switches  11162   a ,  11162   b  indicate articulate center (1) and (2), and switches  11164   a ,  11164   b  indicate reverse/left and reverse/right. For example,  FIG. 76  illustrates one embodiment of a switch bank  11300  comprising a plurality of switches SW 1 -SW 16  configured to control one or more operations of a surgical instrument. The switch bank  11300  may be coupled to a primary processor, such as, for example, the primary processor  11106 . In some embodiments, one or more diodes D 1 -D 8  are coupled to the plurality of switches SW 1 -SW 16 . Any suitable mechanical, electromechanical, or solid state switches may be employed to implement the plurality of switches  11156 - 11170 , in any combination. For example, the switches  11156 - 11170  may limit switches operated by the motion of components associated with the surgical instrument  2000  or the presence of an object. Such switches may be employed to control various functions associated with the surgical instrument  2000 . A limit switch is an electromechanical device that consists of an actuator mechanically linked to a set of contacts. When an object comes into contact with the actuator, the device operates the contacts to make or break an electrical connection. Limit switches are used in a variety of applications and environments because of their ruggedness, ease of installation, and reliability of operation. They can determine the presence or absence, passing, positioning, and end of travel of an object. In other implementations, the switches  11156 - 11170  may be solid state switches that operate under the influence of a magnetic field such as Hall-effect devices, magneto-resistive (MR) devices, giant magneto-resistive (GMR) devices, magnetometers, among others. In other implementations, the switches  11156 - 11170  may be solid state switches that operate under the influence of light, such as optical sensors, infrared sensors, ultraviolet sensors, among others. Still, the switches  11156 - 11170  may be solid state devices such as transistors (e.g., FET, Junction-FET, metal-oxide semiconductor-FET (MOSFET), bipolar, and the like). Other switches may include wireless switches, ultrasonic switches, accelerometers, inertial sensors, among others. 
       FIG. 77  illustrates one embodiment of a switch bank  11350  comprising a plurality of switches. In various embodiments, one or more switches are configured to control one or more operations of a surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 69-71B . A plurality of articulation switches SW 1 -SW 16  is configured to control articulation of a shaft  2004  and/or an end effector  2006  coupled to the surgical instrument  2000 . A firing trigger  11366  is configured to fire the surgical instrument  2000 , for example, to deploy a plurality of staples, translate a cutting member within the end effector  2006 , and/or deliver electrosurgical energy to the end effector  2006 . In some embodiments, the switch bank  11350  comprises one or more safety switches configured to prevent operation of the surgical instrument  2000 . For example, a bailout switch  11356  is coupled to a bailout door and prevents operation of the surgical instrument  2000  when the bailout door is in an open position. 
       FIGS. 78A and 78B  illustrate one embodiment of a segmented circuit  11400  comprising a switch bank  11450  coupled to the primary processor  11406 . The switch bank  11450  is similar to the switch bank  11350  illustrated in  FIG. 77 . The switch bank  11450  comprises a plurality of switches SW 1 -SW 16  configured to control one or more operations of a surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 69-71B . The switch bank  11450  is coupled to an analog input of the primary processor  11406 . Each of the switches within the switch bank  11450  is further coupled to an input/output expander  11463  coupled to a digital input of the primary processor  11406 . The primary processor  11406  receives input from the switch bank  11450  and controls one or more additional segments of the segmented circuit  11400 , such as, for example, a motor segment  11402   g  in response to manipulation of one or more switches of the switch bank  11450 . 
     In some embodiments, a potentiometer  11469  is coupled to the primary processor  11406  to provide a signal indicative of a clamp position of an end effector  2006  coupled to the surgical instrument  2000 . The potentiometer  11469  may replace and/or supplement a safety processor (not shown) by providing a signal indicative of a clamp open/closed position used by the primary processor  11106  to control operation of one or more circuit segments, such as, for example, the motor segment  11102   g . For example, when the potentiometer  11469  indicates that the end effector is in a fully clamped position and/or a fully open position, the primary processor  11406  may open the motor power switch  11420  and prevent further operation of the motor segment  11402   g  in a specific direction. In some embodiments, the primary processor  11406  controls the current delivered to the motor segment  11402   g  in response to a signal received from the potentiometer  11469 . For example, the primary processor  11406  may limit the energy that can be delivered to the motor segment  11402   g  when the potentiometer  11469  indicates that the end effector is closed beyond a predetermined position. 
     Referring back to  FIGS. 73A and 73B , the segmented circuit  11100  comprises an acceleration segment  11102   c . The acceleration segment comprises an accelerometer  11122 . The accelerometer  11122  may be coupled to the safety processor  11104  and/or the primary processor  11106 . The accelerometer  11122  is configured to monitor movement of the surgical instrument  2000 . The accelerometer  11122  is configured to generate one or more signals indicative of movement in one or more directions. For example, in some embodiments, the accelerometer  11122  is configured to monitor movement of the surgical instrument  2000  in three directions. In other embodiments, the acceleration segment  11102   c  comprises a plurality of accelerometers  11122 , each configured to monitor movement in a signal direction. 
     In some embodiments, the accelerometer  11122  is configured to initiate a transition to and/or from a sleep mode, e.g., between sleep-mode and wake-up mode and vice versa. Sleep mode may comprise a low-power mode in which one or more of the circuit segments  11102   a - 11102   g  are deactivated or placed in a low-power state. For example, in one embodiment, the accelerometer  11122  remains active in sleep mode and the safety processor  11104  is placed into a low-power mode in which the safety processor  11104  monitors the accelerometer  11122 , but otherwise does not perform any functions. The remaining circuit segments  11102   b - 11102   g  are powered off. In various embodiments, the primary processor  11104  and/or the safety processor  11106  are configured to monitor the accelerometer  11122  and transition the segmented circuit  11100  to sleep mode, for example, when no movement is detected within a predetermined time period. Although described in connection with the safety processor  11104  monitoring the accelerometer  11122 , the sleep-mode/wake-up mode may be implemented by the safety processor  11104  monitoring any of the sensors, switches, or other indicators associated with the surgical instrument  2000  as described herein. For example, the safety processor  11104  may monitor an inertial sensor, or a one or more switches. 
     In some embodiments, the segmented circuit  11100  transitions to sleep mode after a predetermined period of inactivity. A timer is in signal communication with the safety processor  11104  and/or the primary processor  11106 . The timer may be integral with the safety processor  11104 , the primary processor  11106 , and/or may be a separate circuit component. The timer is configured to monitor a time period since a last movement of the surgical instrument  2000  was detected by the accelerometer  11122 . When the counter exceeds a predetermined threshold, the safety processor  11104  and/or the primary processor  11106  transitions the segmented circuit  11100  into sleep mode. In some embodiments, the timer is reset each time the accelerometer  11122  detects movement. 
     In some embodiments, all circuit segments except the accelerometer  11122 , or other designated sensors and/or switches, and the safety processor  11104  are deactivated when in sleep mode. The safety processor  11104  monitors the accelerometer  11122 , or other designated sensors and/or switches. When the accelerometer  11122  indicates movement of the surgical instrument  2000 , the safety processor  11104  initiates a transition from sleep mode to operational mode. In operational mode, all of the circuit segments  11102   a - 11102   h  are fully energized and the surgical instrument  2000  is ready for use. In some embodiments, the safety processor  11104  transitions the segmented circuit  11100  to the operational mode by providing a signal to the primary processor  11106  to transition the primary processor  11106  from sleep mode to a full power mode. The primary processor  11106 , then transitions each of the remaining circuit segments  11102   d - 11102   h  to operational mode. 
     The transition to and/or from sleep mode may comprise a plurality of stages. For example, in one embodiment, the segmented circuit  11100  transitions from the operational mode to the sleep mode in four stages. The first stage is initiated after the accelerometer  11122  has not detected movement of the surgical instrument for a first predetermined time period. After the first predetermined time period the segmented circuit  11100  dims a backlight of the display segment  11102   d . When no movement is detected within a second predetermined period, the safety processor  11104  transitions to a second stage, in which the backlight of the display segment  11102   d  is turned off. When no movement is detected within a third predetermined time period, the safety processor  11104  transitions to a third stage, in which the polling rate of the accelerometer  11122  is reduced. When no movement is detected within a fourth predetermined time period, the display segment  11102   d  is deactivated and the segmented circuit  11100  enters sleep mode. In sleep mode, all of the circuit segments except the accelerometer  11122  and the safety processor  11104  are deactivated. The safety processor  11104  enters a low-power mode in which the safety processor  11104  only polls the accelerometer  11122 . The safety processor  11104  monitors the accelerometer  11122  until the accelerometer  11122  detects movement, at which point the safety processor  11104  transitions the segmented circuit  11100  from sleep mode to the operational mode. 
     In some embodiments, the safety processor  11104  transitions the segmented circuit  11100  to the operational mode only when the accelerometer  11122  detects movement of the surgical instrument  2000  above a predetermined threshold. By responding only to movement above a predetermined threshold, the safety processor  11104  prevents inadvertent transition of the segmented circuit  11100  to operational mode when the surgical instrument  2000  is bumped or moved while stored. In some embodiments, the accelerometer  11122  is configured to monitor movement in a plurality of directions. For example, the accelerometer  11122  may be configured to detect movement in a first direction and a second direction. The safety processor  11104  monitors the accelerometer  11122  and transitions the segmented circuit  11100  from sleep mode to operational mode when movement above a predetermined threshold is detected in both the first direction and the second direction. By requiring movement above a predetermined threshold in at least two directions, the safety processor  11104  is configured to prevent inadvertent transition of the segmented circuit  11100  from sleep mode due to incidental movement during storage. 
     In some embodiments, the accelerometer  11122  is configured to detect movement in a first direction, a second direction, and a third direction. The safety processor  11104  monitors the accelerometer  11122  and is configured to transition the segmented circuit  11100  from sleep mode only when the accelerometer  11122  detects oscillating movement in each of the first direction, second direction, and third direction. In some embodiments, oscillating movement in each of a first direction, a second direction, and a third direction correspond to movement of the surgical instrument  2000  by an operator and therefore transition to the operational mode is desirable when the accelerometer  11122  detects oscillating movement in three directions. 
     In some embodiments, as the time since the last movement detected increases, the predetermined threshold of movement required to transition the segmented circuit  11100  from sleep mode also increases. For example, in some embodiments, the timer continues to operate during sleep mode. As the timer count increases, the safety processor  11104  increases the predetermined threshold of movement required to transition the segmented circuit  11100  to operational mode. The safety processor  11104  may increase the predetermined threshold to an upper limit. For example, in some embodiments, the safety processor  11104  transitions the segmented circuit  11100  to sleep mode and resets the timer. The predetermined threshold of movement is initially set to a low value, requiring only a minor movement of the surgical instrument  2000  to transition the segmented circuit  11100  from sleep mode. As the time since the transition to sleep mode, as measured by the timer, increases, the safety processor  11104  increases the predetermined threshold of movement. At a time T, the safety processor  11104  has increased the predetermined threshold to an upper limit. For all times T+, the predetermined threshold maintains a constant value of the upper limit. 
     In some embodiments, one or more additional and/or alternative sensors are used to transition the segmented circuit  11100  between sleep mode and operational mode. For example, in one embodiment, a touch sensor is located on the surgical instrument  2000 . The touch sensor is coupled to the safety processor  11104  and/or the primary processor  11106 . The touch sensor is configured to detect user contact with the surgical instrument  2000 . For example, the touch sensor may be located on the handle of the surgical instrument  2000  to detect when an operator picks up the surgical instrument  2000 . The safety processor  11104  transitions the segmented circuit  11100  to sleep mode after a predetermined period has passed without the accelerometer  11122  detecting movement. The safety processor  11104  monitors the touch sensor and transitions the segmented circuit  11100  to operational mode when the touch sensor detects user contact with the surgical instrument  2000 . The touch sensor may comprise, for example, a capacitive touch sensor, a temperature sensor, and/or any other suitable touch sensor. In some embodiments, the touch sensor and the accelerometer  11122  may be used to transition the device between sleep mode and operation mode. For example, the safety processor  11104  may only transition the device to sleep mode when the accelerometer  11122  has not detected movement within a predetermined period and the touch sensor does not indicate a user is in contact with the surgical instrument  2000 . Those skilled in the art will recognize that one or more additional sensors may be used to transition the segmented circuit  11100  between sleep mode and operational mode. In some embodiments, the touch sensor is only monitored by the safety processor  11104  when the segmented circuit  11100  is in sleep mode. 
     In some embodiments, the safety processor  11104  is configured to transition the segmented circuit  11100  from sleep mode to the operational mode when one or more handle controls are actuated. After transitioning to sleep mode, such as, for example, after the accelerometer  11122  has not detected movement for a predetermined period, the safety processor  11104  monitors one or more handle controls, such as, for example, the plurality of articulation switches  11158   a - 11164   b . In other embodiments, the one or more handle controls comprise, for example, a clamp control  11166 , a release button  11168 , and/or any other suitable handle control. An operator of the surgical instrument  2000  may actuate one or more of the handle controls to transition the segmented circuit  11100  to operational mode. When the safety processor  11104  detects the actuation of a handle control, the safety processor  11104  initiates the transition of the segmented circuit  11100  to operational mode. Because the primary processor  11106  is in not active when the handle control is actuated, the operator can actuate the handle control without causing a corresponding action of the surgical instrument  2000 . 
       FIG. 84  illustrates one embodiment of a segmented circuit  11900  comprising an accelerometer  11922  configured to monitor movement of a surgical instrument, such as, for example, the surgical instrument  2000  illustrated in  FIGS. 69-71B . A power segment  11902  provides power from a battery  11908  to one or more circuit segments, such as, for example, the accelerometer  11922 . The accelerometer  11922  is coupled to a processor  11906 . The accelerometer  11922  is configured to monitor movement the surgical instrument  2000 . The accelerometer  11922  is configured to generate one or more signals indicative of movement in one or more directions. For example, in some embodiments, the accelerometer  11922  is configured to monitor movement of the surgical instrument  2000  in three directions. 
     In certain instances, the processor  11906  may be an LM 4F230H5QR, available from Texas Instruments, for example. The processor  11906  is configured to monitor the accelerometer  11922  and transition the segmented circuit  11900  to sleep mode, for example, when no movement is detected within a predetermined time period. In some embodiments, the segmented circuit  11900  transitions to sleep mode after a predetermined period of inactivity. For example, a safety processor  11904  may transitions the segmented circuit  11900  to sleep mode after a predetermined period has passed without the accelerometer  11922  detecting movement. In certain instances, the accelerometer  11922  may be an LIS331DLM, available from STMicroelectronics, for example. A timer is in signal communication with the processor  11906 . The timer may be integral with the processor  11906  and/or may be a separate circuit component. The timer is configured to count time since a last movement of the surgical instrument  2000  was detected by the accelerometer  11922 . When the counter exceeds a predetermined threshold, the processor  11906  transitions the segmented circuit  11900  into sleep mode. In some embodiments, the timer is reset each time the accelerometer  11922  detects movement. 
     In some embodiments, the accelerometer  11922  is configured to detect an impact event. For example, when a surgical instrument  2000  is dropped, the accelerometer  11922  will detect acceleration due to gravity in a first direction and then a change in acceleration in a second direction (caused by impact with a floor and/or other surface). As another example, when the surgical instrument  2000  impacts a wall, the accelerometer  11922  will detect a spike in acceleration in one or more directions. When the accelerometer  11922  detects an impact event, the processor  11906  may prevent operation of the surgical instrument  2000 , as impact events can loosen mechanical and/or electrical components. In some embodiments, only impacts above a predetermined threshold prevent operation. In other embodiments, all impacts are monitored and cumulative impacts above a predetermined threshold may prevent operation of the surgical instrument  2000 . 
     With reference back to  FIGS. 73A and 73B , in one embodiment, the segmented circuit  11100  comprises a power segment  11102   h . The power segment  11102   h  is configured to provide a segment voltage to each of the circuit segments  11102   a - 11102   g . The power segment  11102   h  comprises a battery  11108 . The battery  11108  is configured to provide a predetermined voltage, such as, for example, 12 volts through battery connector  11110 . One or more power converters  11114   a ,  11114   b ,  11116  are coupled to the battery  11108  to provide a specific voltage. For example, in the illustrated embodiments, the power segment  11102   h  comprises an axillary switching converter  11114   a , a switching converter  11114   b , and a low-drop out (LDO) converter  11116 . The switch converters  11114   a ,  11114   b  are configured to provide 3.3 volts to one or more circuit components. The LDO converter  11116  is configured to provide 5.0 volts to one or more circuit components. In some embodiments, the power segment  11102   h  comprises a boost converter  11118 . A transistor switch (e.g., N-Channel MOSFET)  11115  is coupled to the power converters  11114   b ,  11116 . The boost converter  11118  is configured to provide an increased voltage above the voltage provided by the battery  11108 , such as, for example, 13 volts. The boost converter  11118  may comprise, for example, a capacitor, an inductor, a battery, a rechargeable battery, and/or any other suitable boost converter for providing an increased voltage. The boost converter  11118  provides a boosted voltage to prevent brownouts and/or low-power conditions of one or more circuit segments  11102   a - 11102   g  during power-intensive operations of the surgical instrument  2000 . The embodiments, however, are not limited to the voltage range(s) described in the context of this specification. 
     In some embodiments, the segmented circuit  11100  is configured for sequential start-up. An error check is performed by each circuit segment  11102   a - 11102   g  prior to energizing the next sequential circuit segment  11102   a - 11102   g .  FIG. 79  illustrates one embodiment of a process for sequentially energizing a segmented circuit  11270 , such as, for example, the segmented circuit  11100 . When a battery  11108  is coupled to the segmented circuit  11100 , the safety processor  11104  is energized  11272 . The safety processor  11104  performs a self-error check  11274 . When an error is detected  11276   a , the safety processor stops energizing the segmented circuit  11100  and generates an error code  11278   a . When no errors are detected  11276   b , the safety processor  11104  initiates  11278   b  power-up of the primary processor  11106 . The primary processor  11106  performs a self-error check. When no errors are detected, the primary processor  11106  begins sequential power-up of each of the remaining circuit segments  11278   b . Each circuit segment is energized and error checked by the primary processor  11106 . When no errors are detected, the next circuit segment is energized  11278   b . When an error is detected, the safety processor  11104  and/or the primary process stops energizing the current segment and generates an error  11278   a . The sequential start-up continues until all of the circuit segments  11102   a - 11102   g  have been energized. In some embodiments, the segmented circuit  11100  transitions from sleep mode following a similar sequential power-up process  11250 . 
       FIG. 80  illustrates one embodiment of a power segment  11502  comprising a plurality of daisy chained power converters  11514 ,  11516 ,  11518 . The power segment  11502  comprises a battery  11508 . The battery  11508  is configured to provide a source voltage, such as, for example, 12V. A current sensor  11512  is coupled to the battery  11508  to monitor the current draw of a segmented circuit and/or one or more circuit segments. The current sensor  11512  is coupled to an FET switch  11513 . The battery  11508  is coupled to one or more voltage converters  11509 ,  11514 ,  11516 . An always on converter  11509  provides a constant voltage to one or more circuit components, such as, for example, a motion sensor  11522 . The always on converter  11509  comprises, for example, a 3.3V converter. The always on converter  11509  may provide a constant voltage to additional circuit components, such as, for example, a safety processor (not shown). The battery  11508  is coupled to a boost converter  11518 . The boost converter  11518  is configured to provide a boosted voltage above the voltage provided by the battery  11508 . For example, in the illustrated embodiment, the battery  11508  provides a voltage of 12V. The boost converter  11518  is configured to boost the voltage to 13V. The boost converter  11518  is configured to maintain a minimum voltage during operation of a surgical instrument, for example, the surgical instrument  2000  illustrated in  FIGS. 69-71B . Operation of a motor can result in the power provided to the primary processor  11506  dropping below a minimum threshold and creating a brownout or reset condition in the primary processor  11506 . The boost converter  11518  ensures that sufficient power is available to the primary processor  11506  and/or other circuit components, such as the motor controller  11543 , during operation of the surgical instrument  2000 . In some embodiments, the boost converter  11518  is coupled directly one or more circuit components, such as, for example, an OLED display  11588 . 
     The boost converter  11518  is coupled to a one or more step-down converters to provide voltages below the boosted voltage level. A first voltage converter  11516  is coupled to the boost converter  11518  and provides a first stepped-down voltage to one or more circuit components. In the illustrated embodiment, the first voltage converter  11516  provides a voltage of 5V. The first voltage converter  11516  is coupled to a rotary position encoder  11540 . A FET switch  11517  is coupled between the first voltage converter  11516  and the rotary position encoder  11540 . The FET switch  11517  is controlled by the processor  11506 . The processor  11506  opens the FET switch  11517  to deactivate the position encoder  11540 , for example, during power intensive operations. The first voltage converter  11516  is coupled to a second voltage converter  11514  configured to provide a second stepped-down voltage. The second stepped-down voltage comprises, for example, 3.3V. The second voltage converter  11514  is coupled to a processor  11506 . In some embodiments, the boost converter  11518 , the first voltage converter  11516 , and the second voltage converter  11514  are coupled in a daisy chain configuration. The daisy chain configuration allows the use of smaller, more efficient converters for generating voltage levels below the boosted voltage level. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
       FIG. 81  illustrates one embodiment of a segmented circuit  11600  configured to maximize power available for critical and/or power intense functions. The segmented circuit  11600  comprises a battery  11608 . The battery  11608  is configured to provide a source voltage such as, for example, 12V. The source voltage is provided to a plurality of voltage converters  11609 ,  11618 . An always-on voltage converter  11609  provides a constant voltage to one or more circuit components, for example, a motion sensor  11622  and a safety processor  11604 . The always-on voltage converter  11609  is directly coupled to the battery  11608 . The always-on converter  11609  provides a voltage of, for example, 3.3V. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
     The segmented circuit  11600  comprises a boost converter  11618 . The boost converter  11618  provides a boosted voltage above the source voltage provided by the battery  11608 , such as, for example, 13V. The boost converter  11618  provides a boosted voltage directly to one or more circuit components, such as, for example, an OLED display  11688  and a motor controller  11643 . By coupling the OLED display  11688  directly to the boost converter  11618 , the segmented circuit  11600  eliminates the need for a power converter dedicated to the OLED display  11688 . The boost converter  11618  provides a boosted voltage to the motor controller  11643  and the motor  11648  during one or more power intensive operations of the motor  11648 , such as, for example, a cutting operation. The boost converter  11618  is coupled to a step-down converter  11616 . The step-down converter  11616  is configured to provide a voltage below the boosted voltage to one or more circuit components, such as, for example, 5V. The step-down converter  11616  is coupled to, for example, an FET switch  11651  and a position encoder  11640 . The FET switch  11651  is coupled to the primary processor  11606 . The primary processor  11606  opens the FET switch  11651  when transitioning the segmented circuit  11600  to sleep mode and/or during power intensive functions requiring additional voltage delivered to the motor  11648 . Opening the FET switch  11651  deactivates the position encoder  11640  and eliminates the power draw of the position encoder  11640 . The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
     The step-down converter  11616  is coupled to a linear converter  11614 . The linear converter  11614  is configured to provide a voltage of, for example, 3.3V. The linear converter  11614  is coupled to the primary processor  11606 . The linear converter  11614  provides an operating voltage to the primary processor  11606 . The linear converter  11614  may be coupled to one or more additional circuit components. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
     The segmented circuit  11600  comprises a bailout switch  11656 . The bailout switch  11656  is coupled to a bailout door on the surgical instrument  2000 . The bailout switch  11656  and the safety processor  11604  are coupled to an AND gate  11619 . The AND gate  11619  provides an input to a FET switch  11613 . When the bailout switch  11656  detects a bailout condition, the bailout switch  11656  provides a bailout shutdown signal to the AND gate  11619 . When the safety processor  11604  detects an unsafe condition, such as, for example, due to a sensor mismatch, the safety processor  11604  provides a shutdown signal to the AND gate  11619 . In some embodiments, both the bailout shutdown signal and the shutdown signal are high during normal operation and are low when a bailout condition or an unsafe condition is detected. When the output of the AND gate  11619  is low, the FET switch  11613  is opened and operation of the motor  11648  is prevented. In some embodiments, the safety processor  11604  utilizes the shutdown signal to transition the motor  11648  to an off state in sleep mode. A third input to the FET switch  11613  is provided by a current sensor  11612  coupled to the battery  11608 . The current sensor  11612  monitors the current drawn by the circuit  11600  and opens the FET switch  11613  to shut-off power to the motor  11648  when an electrical current above a predetermined threshold is detected. The FET switch  11613  and the motor controller  11643  are coupled to a bank of FET switches  11645  configured to control operation of the motor  11648 . 
     A motor current sensor  11646  is coupled in series with the motor  11648  to provide a motor current sensor reading to a current monitor  11647 . The current monitor  11647  is coupled to the primary processor  11606 . The current monitor  11647  provides a signal indicative of the current draw of the motor  11648 . The primary processor  11606  may utilize the signal from the motor current  11647  to control operation of the motor, for example, to ensure the current draw of the motor  11648  is within an acceptable range, to compare the current draw of the motor  11648  to one or more other parameters of the circuit  11600  such as, for example, the position encoder  11640 , and/or to determine one or more parameters of a treatment site. In some embodiments, the current monitor  11647  may be coupled to the safety processor  11604 . 
     In some embodiments, actuation of one or more handle controls, such as, for example, a firing trigger, causes the primary processor  11606  to decrease power to one or more components while the handle control is actuated. For example, in one embodiment, a firing trigger controls a firing stroke of a cutting member. The cutting member is driven by the motor  11648 . Actuation of the firing trigger results in forward operation of the motor  11648  and advancement of the cutting member. During firing, the primary processor  11606  closes the FET switch  11651  to remove power from the position encoder  11640 . The deactivation of one or more circuit components allows higher power to be delivered to the motor  11648 . When the firing trigger is released, full power is restored to the deactivated components, for example, by closing the FET switch  11651  and reactivating the position encoder  11640 . 
     In some embodiments, the safety processor  11604  controls operation of the segmented circuit  11600 . For example, the safety processor  11604  may initiate a sequential power-up of the segmented circuit  11600 , transition of the segmented circuit  11600  to and from sleep mode, and/or may override one or more control signals from the primary processor  11606 . For example, in the illustrated embodiment, the safety processor  11604  is coupled to the step-down converter  11616 . The safety processor  11604  controls operation of the segmented circuit  11600  by activating or deactivating the step-down converter  11616  to provide power to the remainder of the segmented circuit  11600 . 
       FIG. 82  illustrates one embodiment of a power system  11700  comprising a plurality of daisy chained power converters  11714 ,  11716 ,  11718  configured to be sequentially energized. The plurality of daisy chained power converters  11714 ,  11716 ,  11718  may be sequentially activated by, for example, a safety processor during initial power-up and/or transition from sleep mode. The safety processor may be powered by an independent power converter (not shown). For example, in one embodiment, when a battery voltage VBATT is coupled to the power system  11700  and/or an accelerometer detects movement in sleep mode, the safety processor initiates a sequential start-up of the daisy chained power converters  11714 ,  11716 ,  11718 . The safety processor activates the 13V boost section  11718 . The boost section  11718  is energized and performs a self-check. In some embodiments, the boost section  11718  comprises an integrated circuit  11720  configured to boost the source voltage and to perform a self check. A diode D prevents power-up of a 5V supply section  11716  until the boost section  11718  has completed a self-check and provided a signal to the diode D indicating that the boost section  11718  did not identify any errors. In some embodiments, this signal is provided by the safety processor. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
     The 5V supply section  11716  is sequentially powered-up after the boost section  11718 . The 5V supply section  11716  performs a self-check during power-up to identify any errors in the 5V supply section  11716 . The 5V supply section  11716  comprises an integrated circuit  11715  configured to provide a step-down voltage from the boost voltage and to perform an error check. When no errors are detected, the 5V supply section  11716  completes sequential power-up and provides an activation signal to the 3.3V supply section  11714 . In some embodiments, the safety processor provides an activation signal to the 3.3V supply section  11714 . The 3.3V supply section comprises an integrated circuit  11713  configured to provide a step-down voltage from the 5V supply section  11716  and perform a self-error check during power-up. When no errors are detected during the self-check, the 3.3V supply section  11714  provides power to the primary processor. The primary processor is configured to sequentially energize each of the remaining circuit segments. By sequentially energizing the power system  11700  and/or the remainder of a segmented circuit, the power system  11700  reduces error risks, allows for stabilization of voltage levels before loads are applied, and prevents large current draws from all hardware being turned on simultaneously in an uncontrolled manner. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
     In one embodiment, the power system  11700  comprises an over voltage identification and mitigation circuit. The over voltage identification and mitigation circuit is configured to detect a monopolar return current in the surgical instrument and interrupt power from the power segment when the monopolar return current is detected. The over voltage identification and mitigation circuit is configured to identify ground floatation of the power system. The over voltage identification and mitigation circuit comprises a metal oxide varistor. The over voltage identification and mitigation circuit comprises at least one transient voltage suppression diode. 
       FIG. 83  illustrates one embodiment of a segmented circuit  11800  comprising an isolated control section  11802 . The isolated control section  11802  isolates control hardware of the segmented circuit  11800  from a power section (not shown) of the segmented circuit  11800 . The control section  11802  comprises, for example, a primary processor  11806 , a safety processor (not shown), and/or additional control hardware, for example, a FET Switch  11817 . The power section comprises, for example, a motor, a motor driver, and/or a plurality of motor MOSFETS. The isolated control section  11802  comprises a charging circuit  11803  and a rechargeable battery  11808  coupled to a 5V power converter  11816 . The charging circuit  11803  and the rechargeable battery  11808  isolate the primary processor  11806  from the power section. In some embodiments, the rechargeable battery  11808  is coupled to a safety processor and any additional support hardware. Isolating the control section  11802  from the power section allows the control section  11802 , for example, the primary processor  11806 , to remain active even when main power is removed, provides a filter, through the rechargeable battery  11808 , to keep noise out of the control section  11802 , isolates the control section  11802  from heavy swings in the battery voltage to ensure proper operation even during heavy motor loads, and/or allows for real-time operating system (RTOS) to be used by the segmented circuit  11800 . In some embodiments, the rechargeable battery  11808  provides a stepped-down voltage to the primary processor, such as, for example, 3.3V. The embodiments, however, are not limited to the particular voltage range(s) described in the context of this specification. 
       FIG. 85  illustrates one embodiment of a process for sequential start-up of a segmented circuit, such as, for example, the segmented circuit  11100  illustrated in  FIGS. 73A and 73B . The sequential start-up process  11820  begins when one or more sensors initiate a transition from sleep mode to operational mode. When the one or more sensors stop detecting state changes  11822 , a timer is started  11824 . The timer counts the time since the last movement/interaction with the surgical instrument  2000  was detected by the one or more sensors. The timer count is compared  11826  to a table of sleep mode stages by, for example, the safety processor  11104 . When the timer count exceeds one or more counts for transition to a sleep mode stage  11828   a , the safety processor  11104  stops energizing  11830  the segmented circuit  11100  and transitions the segmented circuit  11100  to the corresponding sleep mode stage. When the timer count is below the threshold for any of the sleep mode stages  11828   b , the segmented circuit  11100  continues to sequentially energize the next circuit segment  11832 . 
     With reference back to  FIGS. 73A and 73B , in some embodiments, the segmented circuit  11100  comprises one or more environmental sensors to detect improper storage and/or treatment of a surgical instrument. For example, in one embodiment, the segmented circuit  11100  comprises a temperature sensor. The temperature sensor is configured to detect the maximum and/or minimum temperature that the segmented circuit  11100  is exposed to. The surgical instrument  2000  and the segmented circuit  11100  comprise a design limit exposure for maximum and/or minimum temperatures. When the surgical instrument  2000  is exposed to temperatures exceeding the limits, for example, a temperature exceeding the maximum limit during a sterilization technique, the temperature sensor detects the overexposure and prevents operation of the device. The temperature sensor may comprise, for example, a bi-metal strip configured to disable the surgical instrument  2000  when exposed to a temperature above a predetermined threshold, a solid-state temperature sensor configured to store temperature data and provide the temperature data to the safety processor  11104 , and/or any other suitable temperature sensor. 
     In some embodiments, the accelerometer  11122  is configured as an environmental safety sensor. The accelerometer  11122  records the acceleration experienced by the surgical instrument  2000 . Acceleration above a predetermined threshold may indicate, for example, that the surgical instrument has been dropped. The surgical instrument comprises a maximum acceleration tolerance. When the accelerometer  11122  detects acceleration above the maximum acceleration tolerance, safety processor  11104  prevents operation of the surgical instrument  2000 . 
     In some embodiments, the segmented circuit  11100  comprises a moisture sensor. The moisture sensor is configured to indicate when the segmented circuit  11100  has been exposed to moisture. The moisture sensor may comprise, for example, an immersion sensor configured to indicate when the surgical instrument  2000  has been fully immersed in a cleaning fluid, a moisture sensor configured to indicate when moisture is in contact with the segmented circuit  11100  when the segmented circuit  11100  is energized, and/or any other suitable moisture sensor. 
     In some embodiments, the segmented circuit  11100  comprises a chemical exposure sensor. The chemical exposure sensor is configured to indicate when the surgical instrument  2000  has come into contact with harmful and/or dangerous chemicals. For example, during a sterilization procedure, an inappropriate chemical may be used that leads to degradation of the surgical instrument  2000 . The chemical exposure sensor may indicate inappropriate chemical exposure to the safety processor  11104 , which may prevent operation of the surgical instrument  2000 . 
     The segmented circuit  11100  is configured to monitor a number of usage cycles. For example, in one embodiment, the battery  11108  comprises a circuit configured to monitor a usage cycle count. In some embodiments, the safety processor  11104  is configured to monitor the usage cycle count. Usage cycles may comprise surgical events initiated by a surgical instrument, such as, for example, the number of shafts  2004  used with the surgical instrument  2000 , the number of cartridges inserted into and/or deployed by the surgical instrument  2000 , and/or the number of firings of the surgical instrument  2000 . In some embodiments, a usage cycle may comprise an environmental event, such as, for example, an impact event, exposure to improper storage conditions and/or improper chemicals, a sterilization process, a cleaning process, and/or a reconditioning process. In some embodiments, a usage cycle may comprise a power assembly (e.g., battery pack) exchange and/or a charging cycle. 
     The segmented circuit  11100  may maintain a total usage cycle count for all defined usage cycles and/or may maintain individual usage cycle counts for one or more defined usage cycles. For example, in one embodiment, the segmented circuit  11100  may maintain a single usage cycle count for all surgical events initiated by the surgical instrument  2000  and individual usage cycle counts for each environmental event experienced by the surgical instrument  2000 . The usage cycle count is used to enforce one or more behaviors by the segmented circuit  11100 . For example, usage cycle count may be used to disable a segmented circuit  11100 , for example, by disabling a battery  11108 , when the number of usage cycles exceeds a predetermined threshold or exposure to an inappropriate environmental event is detected. In some embodiments, the usage cycle count is used to indicate when suggested and/or mandatory service of the surgical instrument  2000  is necessary. 
       FIG. 86  illustrates one embodiment of a method  11950  for controlling a surgical instrument comprising a segmented circuit, such as, for example, the segmented control circuit  11602  illustrated in  FIG. 80 . At  11952 , a power assembly  11608  is coupled to the surgical instrument. The power assembly  11608  may comprise any suitable battery, such as, for example, the power assembly  2006  illustrates in  FIGS. 69-71B . The power assembly  11608  is configured to provide a source voltage to the segmented control circuit  11602 . The source voltage may comprise any suitable voltage, such as, for example, 12V. At  11954 , the power assembly  11608  energizes a voltage boost convertor  11618 . The voltage boost convertor  11618  is configured to provide a set voltage. The set voltage comprises a voltage greater than the source voltage provided by the power assembly  11608 . For example, in some embodiments, the set voltage comprises a voltage of 13V. In a third step  11956 , the voltage boost convertor  11618  energizes one or more voltage regulators to provide one or more operating voltages to one or more circuit components. The operating voltages comprise a voltage less than the set voltage provided by the voltage boost convertor. 
     In some embodiments, the boost convertor  11618  is coupled to a first voltage regulator  11616  configured to provide a first operating voltage. The first operating voltage provided by the first voltage regulator  11616  is less than the set voltage provided by the voltage boost convertor. For example, in some embodiments, the first operating voltage comprises a voltage of 5V. In some embodiments, the boost convertor is coupled to a second voltage regulator  11614 . The second voltage regulator  11614  is configured to provide a second operating voltage. The second operating voltage comprises a voltage less than the set voltage and the first operating voltage. For example, in some embodiments, the second operating voltage comprises a voltage of 3.3V. In some embodiments, the battery  11608 , voltage boost convertor  11618 , first voltage regulator  11616 , and second voltage regulator  11614  are configured in a daisy chain configuration. The battery  11608  provides the source voltage to the voltage boost convertor  11618 . The voltage boost convertor  11618  boosts the source voltage to the set voltage. The voltage boost convertor  11618  provides the set voltage to the first voltage regulator  11616 . The first voltage regulator  11616  generates the first operating voltage and provides the first operating voltage to the second voltage regulator  11614 . The second voltage regulator  11614  generates the second operating voltage. 
     In some embodiments, one or more circuit components are energized directly by the voltage boost convertor  11618 . For example, in some embodiments, an OLED display  11688  is coupled directly to the voltage boost convertor  11618 . The voltage boost convertor  11618  provides the set voltage to the OLED display  11688 , eliminating the need for the OLED to have a power generator integral therewith. In some embodiments, a processor, such as, for example, the safety processor  11604  illustrated in  FIGS. 73A and 73B , is verifies the voltage provided by the voltage boost convertor  11618  and/or the one or more voltage regulators  11616 ,  11614 . The safety processor  11604  is configured to verify a voltage provided by each of the voltage boost convertor  11618  and the voltage regulators  11616 ,  11614 . In some embodiments, the safety processor  11604  verifies the set voltage. When the set voltage is equal to or greater than a first predetermined value, the safety processor  11604  energizes the first voltage regulator  11616 . The safety processor  11604  verifies the first operational voltage provided by the first voltage regulator  11616 . When the first operational voltage is equal to or greater than a second predetermined value, the safety processor  11604  energizes the second voltage regulator  11614 . The safety processor  11604  then verifies the second operational voltage. When the second operational voltage is equal to or greater than a third predetermined value, the safety processor  11604  energizes each of the remaining circuit components of the segmented circuit  11600 . 
     Various aspects of the subject matter described herein relate to methods of controlling power management of a surgical instrument through a segmented circuit and variable voltage protection. In one embodiment, a method of controlling power management in a surgical instrument comprising a primary processor, a safety processor, and a segmented circuit comprising a plurality of circuit segments in signal communication with the primary processor, the plurality of circuit segments comprising a power segment, the method comprising providing, by the power segment, variable voltage control of each segment. In one embodiment, the method comprises providing, by the power segment comprising a boost converter, power stabilization for at least one of the segment voltages. The method also comprises providing, by the boost converter, power stabilization to the primary processor and the safety processor. The method also comprises providing, by the boost converter, a constant voltage to the primary processor and the safety processor above a predetermined threshold independent of a power draw of the plurality of circuit segments. The method also comprises detecting, by an over voltage identification and mitigation circuit, a monopolar return current in the surgical instrument and interrupting power from the power segment when the monopolar return current is detected. The method also comprises identifying, by the over voltage identification and mitigation circuit, ground floatation of the power system. 
     In another embodiment, the method also comprises energizing, by the power segment, each of the plurality of circuit segments sequentially and error checking each circuit segment prior to energizing a sequential circuit segment. The method also comprises energizing the safety processor by a power source coupled to the power segment, performing an error check, by the safety processor, when the safety processor is energized, and performing, and energizing, the safety processor, the primary processor when no errors are detected during the error check. The method also comprises performing an error check, by the primary processor when the primary processor is energized, and wherein when no errors are detected during the error check, sequentially energizing, by the primary processor, each of the plurality of circuit segments. The method also comprises error checking, by the primary processor, each of the plurality of circuit segments. 
     In another embodiment, the method comprises, energizing, by the boost convertor the safety processor when a power source is connected to the power segment, performing, by the safety processor an error check, and energizing the primary processor, by the safety processor, when no errors are detected during the error check. The method also comprises performing an error check, by the primary process, and sequentially energizing, by the primary processor, each of the plurality of circuit segments when no errors are detected during the error check. The method also comprises error checking, by the primary processor, each of the plurality of circuit segments. 
     In another embodiment, the method also comprises, providing, by a power segment, a segment voltage to the primary processor, providing variable voltage protection of each segment, providing, by a boost converter, power stabilization for at least one of the segment voltages, an over voltage identification, and a mitigation circuit, energizing, by the power segment, each of the plurality of circuit segments sequentially, and error checking each circuit segment prior to energizing a sequential circuit segment. 
     Various aspects of the subject matter described herein relate to methods of controlling an surgical instrument control circuit having a safety processor. In one embodiment, a method of controlling a surgical instrument comprising a control circuit comprising a primary processor, a safety processor in signal communication with the primary processor, and a segmented circuit comprising a plurality of circuit segments in signal communication with the primary processor, the method comprising monitoring, by the safety processor, one or more parameters of the plurality of circuit segments. The method also comprises verifying, by the safety processor, the one or more parameters of the plurality of circuit segments and verifying the one or more parameters independently of one or more control signals generated by the primary processor. The method further comprises verifying, by the safety processor, a velocity of a cutting element. The method also comprises monitoring, by a first sensor, a first property of the surgical instrument, monitoring, by a second sensor a second property of the surgical instrument, wherein the first property and the second property comprise a predetermined relationship, and wherein the first sensor and the second sensor are in signal communication with the safety processor. The method also comprises preventing, by the safety processor, operation of at least one of the plurality of circuit segments when the fault is detected, wherein a fault comprises the first property and the second property having values inconsistent with the predetermined relationship. The method also comprises, monitoring, by a Hall-effect sensor, a cutting member position and monitoring, by a motor current sensor, a motor current. 
     In another embodiment, the method comprises disabling, by the safety processor, at least one of the plurality of circuit segments when a mismatch is detected between the verification of the one or more parameters and the one or more control signals generated by the primary processor. The method also comprises preventing by the safety processor, operation of a motor segment and interrupting power flow to the motor segment from the power segment. The method also comprises preventing, by the safety processor, forward operation of a motor segment and when the fault is detected allowing, by the safety processor, reverse operation of the motor segment. 
     In another embodiment the segmented circuit comprises a motor segment and a power segment, the method comprising controlling, by the motor segment, one or more mechanical operations of the surgical instrument and monitoring, by the safety processor, one or more parameters of the plurality of circuit segments. The method also comprises verifying, by the safety processor, the one or more parameters of the plurality of circuit segments and the independently verifying, by the safety processor, the one or more parameters independently of one or more control signals generated by the primary processor. 
     In another embodiment, the method also comprises independently verifying, by the safety processor, the velocity of a cutting element. The method also comprises monitoring, by a first sensor, a first property of the surgical instrument, monitoring, by a second sensor, a second property of the surgical instrument, wherein the first property and the second property comprise a predetermined relationship, and wherein the first sensor and the second sensor are in signal communication with the safety processor, wherein a fault comprises the first property and the second property having values inconsistent with the predetermined relationship, and preventing, by the safety processor, the operation of at least one of the plurality of circuit segments when the fault is detected by the safety processor. The method also comprises monitoring, by a Hall-effect sensor, a cutting member position and monitoring, by a motor current sensor, a motor current. 
     In another embodiment, the method comprises disabling, by the safety processor, at least one of the plurality of circuit segments when a mismatch is detected between the verification of the one or more parameters and the one or more control signals generated by the primary processor. The method also comprises preventing, by the safety processor, operation of the motor segment and interrupting power flow to the motor segment from the power segment. The method also comprises preventing, by the safety processor, forward operation of the motor segment and allowing, by the safety processor, reverse operation of the motor segment when the fault is detected. 
     In another embodiment, the method comprises monitoring, by the safety processor, one or more parameters of the plurality of circuit segments, verifying, by the safety processor, the one or more parameters of the plurality of circuit segments, verifying, by the safety processor, the one or more parameters independently of one or more control signals generated by the primary processor, and disabling, by the safety processor, at least one of the plurality of circuit segments when a mismatch is detected between the verification of the one or more parameters and the one or more control signals generated by the primary processor. The method also comprises monitoring, by a first sensor, a first property of the surgical instrument, monitoring, by a second sensor, a second property of the surgical instrument, wherein the first property and the second property comprise a predetermined relationship, and wherein the first sensor and the second sensor are in signal communication with the safety processor, wherein a fault comprises the first property and the second property having values inconsistent with the predetermined relationship, and wherein when the fault is detected, preventing, by the safety processor, operation of at least one of the plurality of circuit segments. The method also comprises preventing, by the safety processor, operation of a motor segment by interrupting power flow to the motor segment from the power segment when a fault is detected prevent. 
     Various aspects of the subject matter described herein relate to methods of controlling power management of a surgical instrument through sleep options of segmented circuit and wake up control, the surgical instrument comprising a control circuit comprising a primary processor, a safety processor in signal communication with the primary processor, and a segmented circuit comprising a plurality of circuit segments in signal communication with the primary processor, the plurality of circuit segments comprising a power segment, the method comprising transitioning, by the safety processor, the primary processor and at least one of the plurality of circuit segments from an active mode to a sleep mode and from the sleep mode to the active mode. The method also comprises tracking, by a timer, a time from a last user initiated event and wherein when the time from the last user initiated event exceeds a predetermined threshold, transitioning, by the safety processor, the primary processor and at least one of the plurality of circuit segments to the sleep mode. The method also comprises detecting, by an acceleration segment comprising an accelerometer, one or more movements of the surgical instrument. The method also comprises tracking, by the timer, a time from the last movement detected by the acceleration segment. The method also comprises maintaining, by the safety processor, the acceleration segment in the active mode when transitioning the plurality of circuit segments to the sleep mode. 
     In another embodiment, the method also comprises transitioning to the sleep mode in a plurality of stages. The method also comprises transitioning the segmented circuit to a first stage after a first predetermined period and dimming a backlight of the display segment, transitioning the segmented circuit to a second stage after a second predetermined period and turning the backlight off, transitioning the segmented circuit to a third stage after a third predetermined period and reducing a polling rate of the accelerometer, and transitioning the segmented circuit to a fourth stage after a fourth predetermined period and turning a display off and transitioning the surgical instrument to the sleep mode. 
     In another embodiment comprising detecting, by a touch sensor, user contact with a surgical instrument and transitioning, by the safety processor, the primary processor and a plurality of circuit segments from a sleep mode to an active mode when the touch sensor detects a user in contact with surgical instrument. The method also comprises monitoring, by the safety processor, at least one handle control and transitioning, by the safety processor, the primary processor and the plurality of circuit segments from the sleep mode to the active mode when the at least one handle control is actuated. 
     In another embodiment, the method comprises transitioning, by the safety processor, the surgical device to the active mode when the accelerometer detects movement of the surgical instrument above a predetermined threshold. The method also comprises monitoring, by the safety processor, the accelerometer for movement in at least a first direction and a second direction and transitioning, by the safety processor, the surgical instrument from the sleep mode to the operational mode when movement above a predetermined threshold is detected in at least the first direction and the second direction. The method also comprises monitoring, by the safety processor, the accelerometer for oscillating movement above the predetermined threshold in the first direction, the second direction, and a third direction, and transitioning, by the safety processor, the surgical instrument from the sleep mode to the operational mode when oscillating movement is detected above the predetermined threshold in the first direction, second direction, and third direction. The method also comprises increasing the predetermined as the time from the previous movement increases. 
     In another embodiment, the method comprises transitioning, by the safety processor, the primary processor and at least one of the plurality of circuit segments from an active mode to a sleep mode and from the sleep mode to the active mode when a time from the last user initiated event exceeds a predetermined threshold, tracking, by a timer, a time from the last movement detected by the acceleration segment, and transitioning, by the safety processor, the surgical device to the active mode when the acceleration segment detects movement of the surgical instrument above a predetermined threshold. 
     In another embodiment, a method of controlling a surgical instrument comprises tracking a time from a last user initiated event and disabling, by the safety processor, a backlight of a display when the time from the last user initiated event exceeds a predetermined threshold. The method also comprises flashing, by the safety processor, the backlight of the display to indicate to a user to look at the display. 
     Various aspects of the subject matter described herein relate to methods of verifying the sterilization of a surgical instrument through a sterilization verification circuit, the surgical instrument comprising a control circuit comprising a primary processor, a safety processor in signal communication with the primary processor and a segmented circuit comprising a plurality of circuit segments in signal communication with the primary processor, the plurality of circuit segments comprising a storage verification segment, the method comprising indicating when a surgical instrument has been properly stored and sterilized. The method also comprises detecting, by at least one sensor, one or more improper storage or sterilization parameters. The method also comprises sensing, by a drop protection sensor, when the instrument has been dropped and preventing, by the safety processor, operation of at least one of the plurality of circuit segments when the drop protection sensor detects that the surgical instrument has been dropped. The method also comprises preventing, by the safety processor, operation of at least one of the plurality of circuit segments when a temperature above a predetermined threshold is detected by a temperature sensor. The method also comprises preventing, by the safety processor, operation of at least one of the plurality of circuit segments when the temperature sensor detects a temperature above a predetermined threshold. 
     In another embodiment, the method comprises controlling, by the safety processor, operation of at least one of the plurality of circuit segments when a moisture detection sensor detects moisture. The method also comprises detecting, by a moisture detection sensor, an autoclave cycle and preventing, by the safety processor, operation of the surgical instrument unless the autoclave cycle has been detected. The method also comprises preventing, by the safety processor, operation of the at least one of the plurality of circuit segments when moisture is detected during a staged circuit start-up. 
     In another embodiment, the method comprises indicating, by the plurality of circuit segments comprising a sterilization verification segment, when a surgical instrument has been properly sterilized. The method also comprises detecting, by at least one sensor of the sterilization verification segment, sterilization of the surgical instrument. The method also comprises indicating, by a storage verification segment, when a surgical instrument has been properly stored. The method also comprises detecting, by at least one sensor of the storage verification segment, improper storage of the surgical instrument. 
       FIG. 87  generally depicts a motor-driven surgical instrument  12200 . In certain circumstances, the surgical instrument  12200  may include a handle assembly  12202 , a shaft assembly  12204 , and a power assembly  12206  (or “power source” or “power pack”). The shaft assembly  12204  may include an end effector  12208  which, in certain circumstances, can be configured to act as an endocutter for clamping, severing, and/or stapling tissue, although, in other circumstances, different types of end effectors may be used, such as end effectors for other types of surgical devices, graspers, cutters, staplers, clip appliers, access devices, drug/gene therapy devices, ultrasound, RF and/or laser devices, etc. Several RF devices may be found in U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008. The entire disclosures of U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995, and U.S. patent application Ser. No. 12/031,573, entitled SURGICAL FASTENING AND CUTTING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008, are incorporated herein by reference in their entirety. 
     Referring again to  FIG. 87 , the handle assembly  12202  may comprise a housing  12210  that includes a handle  12212  that may be configured to be grasped, manipulated, and/or actuated by a clinician. However, it will be understood that the various unique and novel arrangements of the housing  12210  may also be effectively employed in connection with robotically-controlled surgical systems. Thus, the term “housing” may also encompass a housing or similar portion of a robotic system that houses or otherwise operably supports at least one drive system that is configured to generate and apply at least one control motion which could be used to actuate the shaft assembly  12204  disclosed herein and its respective equivalents. For example, the housing  12210  disclosed herein may be employed with various robotic systems, instruments, components, and methods disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535. The disclosure of U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, is incorporated by reference herein in its entirety. 
     In certain instances, the surgical instrument  12200  may include several operable systems that extend, at least partially, through the shaft  12204  and are in operable engagement with the end effector  12208 . For example, the surgical instrument  12200  may include a closure assembly that may transition the end effector  12208  between an open configuration and a closed configuration, an articulation assembly that may articulate the end effector  12208  relative to the shaft  12204 , and/or a firing assembly that may fasten and/or cut tissue captured by the end effector  12208 . In addition, the housing  12210  may be separably couplable to the shaft  12204  and may include complimenting closure, articulation, and/or firing drive systems for operating the closure, articulation, and firing assemblies, respectively. 
     In use, an operator of the surgical instrument  12200  may desire to reset the surgical instrument  12200  and return one or more of the assemblies of the surgical instrument  12200  to a default position. For example, the operator may insert the end effector  12208  into a surgical site within a patient through an access port and may then articulate and/or close the end effector  12208  to capture tissue within the cavity. The operator may then choose to undo some or all of the previous actions and may choose to remove the surgical instrument  12200  from the cavity, for instance. The surgical instrument  12200  may include one more systems configured to facilitate a reliable return of one or more of the assemblies described above to a home state with minimal input from the operator thereby allowing the operator to remove the surgical instrument from the cavity. 
     Referring to  FIGS. 87 and 89 , the surgical instrument  12200  may include a control system  13000 . A surgical operator may utilize the control system  13000  to articulate the end effector  12208  relative to the shaft  12204  between an articulation home state position and an articulated position, for example. In certain instances, the surgical operator may utilize the control system  13000  to reset or return the articulated end effector  12208  to the articulation home state position. The control system  13000  can be positioned, at least partially, in the housing  12210 . In certain instances, as illustrated in in  FIG. 89 , the control system  13000  may comprise a microcontroller  13002  (“controller”) which can be configured to receive an input signal and, in response, activate a motor  12216  to cause the end effector  12208  to articulate in accordance with such an input signal, for example. 
     Further to the above, the end effector  12208  can be positioned in sufficient alignment with the shaft  12204  in the articulation home state position, also referred to herein as an unarticulated position such that the end effector  12208  and at least a portion of shaft  12204  can be inserted into or retracted from a patient&#39;s internal cavity through an access port such as, for example, a trocar positioned in a wall of the internal cavity without damaging the access port. In certain instances, the end effector  12208  can be aligned, or at least substantially aligned, with a longitudinal axis “LL” passing through the shaft  12204  when the end effector  12208  is in the articulation home state position, as illustrated in  FIG. 87 . In at least one instance, the articulation home state position can be at any angle up to and including 5°, for example, with the longitudinal axis “LL” on either side of the longitudinal axis “LL”. In another instance, the articulation home state position can be at any angle up to and including 3°, for example, with the longitudinal axis “LL” on either side of the longitudinal axis “LL”. In yet another instance, the articulation home state position can be at any angle up to and including 7°, for example, with the longitudinal axis “LL” on either side of the longitudinal axis “LL”. 
     The control system  13000  can be operated to articulate the end effector  12208  relative to the shaft  12204  in a plane extending along the longitudinal axis “LL” in a first direction such as, for example, a clockwise direction and/or a second direction such as, for example, a counterclockwise direction. In at least one instance, the control system  13000  can be operated to articulate the end effector  12208  in the clockwise direction form the articulation home state position to an articulated position 10 degrees to the right of the longitudinal axis “LL”, for example. In another example, the control system  13000  can be operated to articulate the end effector  12208  in the counterclockwise direction form the articulated position at 10 degrees to the right of the longitudinal axis “LL” to the articulation home state position. In yet another example, the control system  13000  can be operated to articulate the end effector  12208  relative to the shaft  12204  in the counterclockwise direction from the articulation home state position to an articulated position 10 degrees to the left of the longitudinal axis “LL”, for example. The reader will appreciate that the end effector can be articulated to different angles in the clockwise direction and/or the counterclockwise direction. 
     Referring to  FIGS. 87 and 88 , the housing  12210  of the surgical instrument  12200  may comprise an interface  13001  which may include a plurality of controls that can be utilized by the operator to operate the surgical instrument  12200 . In certain instances, the interface  13001  may comprise a plurality of switches which can be coupled to the controller  13002  via electrical circuits, for example. In certain instances, as illustrated in  FIG. 89 , the interface  13001  comprises three switches  13004 A-C, wherein each of the switches  13004 A-C is coupled to the controller  13002  via electrical circuits such as, for example electrical circuits  13006 A-C, respectively. The reader will appreciate that other combinations of switches and circuits can be utilized with the interface  13001 . 
     Referring to  FIG. 89 , the controller  13002  may generally comprise a microprocessor  13008  (“processor”) and one or more memory units  13010  operationally coupled to the processor  13008 . By executing instruction code stored in the memory  13010 , the processor  13008  may control various components of the surgical instrument  12200 , such as the motor  12216 , various drive systems, and/or a user display, for example. The controller  13002  may be implemented using integrated and/or discrete hardware elements, software elements, and/or a combination of both. Examples of integrated hardware elements may include processors, microprocessors, microcontrollers, integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate arrays (FPGA), logic gates, registers, semiconductor devices, chips, microchips, chip sets, microcontrollers, system-on-chip (SoC), and/or system-in-package (SIP). Examples of discrete hardware elements may include circuits and/or circuit elements such as logic gates, field effect transistors, bipolar transistors, resistors, capacitors, inductors, and/or relays. In certain instances, the controller  13002  may include a hybrid circuit comprising discrete and integrated circuit elements or components on one or more substrates, for example. 
     In certain instances, the microcontroller  13002  may be an LM 4F230H5QR, available from Texas Instruments, for example. In certain instances, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chip memory of 256 KB single-cycle flash memory, or other non-volatile memory, up to 40 MHz, a prefetch buffer to improve performance above 40 MHz, a 32 KB single-cycle serial random access memory (SRAM), internal read-only memory (ROM) loaded with StellarisWare® software, 2 KB electrically erasable programmable read-only memory (EEPROM), one or more pulse width modulation (PWM) modules, one or more quadrature encoder inputs (QEI) analog, one or more 12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels, among other features that are readily available. Other microcontrollers may be readily substituted for use with the present disclosure. Accordingly, the present disclosure should not be limited in this context. 
     In various forms, the motor  12216  may be a DC brushed driving motor having a maximum rotation of, approximately, 25,000 RPM, for example. In other arrangements, the motor  12216  may include a brushless motor, a cordless motor, a synchronous motor, a stepper motor, or any other suitable electric motor. A battery  12218  (or “power source” or “power pack”), such as a Li ion battery, for example, may be coupled to the housing  12212  to supply power to the motor  12216 , for example. 
     Referring again to  FIG. 89 , the surgical instrument  12200  may include a motor controller  13005  in operable communication with the controller  13002 . The motor controller  13005  can be configured to control a direction of rotation of the motor  12216 . In certain instances, the motor controller  13005  may be configured to determine the voltage polarity applied to the motor  12216  by the battery  12218  and, in turn, determine the direction of rotation of the motor  12216  based on input from the controller  13002 . For example, the motor  12216  may reverse the direction of its rotation from a clockwise direction to a counterclockwise direction when the voltage polarity applied to the motor  12216  by the battery  12218  is reversed by the motor controller  13005  based on input from the controller  13002 . In addition, the motor  12216  can be operably coupled to an articulation drive which can be driven by the motor  12216  distally or proximally depending on the direction in which the motor  12216  rotates, for example. Furthermore, the articulation drive can be operably coupled to the end effector  12208  such that, for example, the axial translation of the articulation drive proximally may cause the end effector  12208  to be articulated in the counterclockwise direction, for example, and/or the axial translation of the articulation drive distally may cause the end effector  12208  to be articulated in the clockwise direction, for example. 
     In various instances, referring to  FIGS. 87-89 , the interface  13001  can be configured such that the switch  13004 A can be dedicated to the clockwise articulation of the end effector  12208 , for example, and the switch  13004 B can be dedicated to the counterclockwise articulation of the end effector  12208 , for example. In such instances, the operator may articulate the end effector  12208  in the clockwise direction by closing the switch  13004 A and may articulate the end effector  12208  in the counterclockwise direction by closing the switch  13004 B. In various instances, the switches  13004 A-C can comprise open-biased dome switches, as illustrated in  FIG. 93 . Other types of switches can also be employed such as, for example, capacitive switches. 
     Referring to  FIG. 93 , the dome switches  13004 A and  13004 B can be controlled by a rocker  13012 . Other means for controlling the switches  13004 A and  13004 B are contemplated by the present disclosure. In the neutral position, as illustrated in  FIG. 93 , both of the switches  13004 A and  13004 B are biased in the open position. The operator, for example, may articulate the end effector  12208  in the clockwise direction by tilting the rocker forward thereby depressing the dome switch  13004 A, as illustrated in  FIG. 94 . In result, the circuit  13006 A ( FIG. 89 ) may be closed signaling the controller  13002  to activate the motor  12216  to articulate the end effector  12208  in the clockwise direction, as described above. The motor  12216  may continue to articulate the end effector  12208  until the operator releases the rocker  13012  thereby allowing the dome switch  13004 A to return to the open position and the rocker  13012  to the neutral position. In some circumstances, the controller  13002  may be able to identify when the end effector  12208  has reached a predetermined maximum degree of articulation and, at such point, interrupt power to the motor  12216  regardless of whether the dome switch  13004 A is being depressed. In a way, the controller  13002  can be configured to override the operator&#39;s input and stop the motor  12216  when a maximum degree of safe articulation is reached. Alternatively, the operator may articulate the end effector  12208  in the counterclockwise direction by tilting the rocker  13012  back thereby depressing the dome switch  13004 B, for example. In result, the circuit  13006 B may be closed signaling the controller  13002  to activate the motor  12216  to articulate the end effector  12208  in the counterclockwise direction, as described above. The motor  12216  may continue to articulate the end effector  12208  until the operator releases the rocker  13012  thereby allowing the dome switch  13004 B to return to the open position and the rocker  13012  to the neutral position. In some circumstances, the controller  13002  may be able to identify when the end effector  12208  has reached a predetermined maximum degree of articulation and, at such point, interrupt power to the motor  12216  regardless of whether the dome switch  13004 B is being depressed. In a way, the controller  13002  can be configured to override the operator&#39;s input and stop the motor  12216  when a maximum degree of safe articulation is reached. 
     As described above in greater detail, an operator may desire to return the end effector  12208  to the articulation home state position to align, or at least substantially align, the end effector  12208  with the shaft  12204  in order to retract the surgical instrument  12200  from a patient&#39;s internal cavity, for example. In various instances, the control system  13000  may include a virtual detent that may alert the operator when the end effector  12208  has reached the articulation home state position. In certain instances, the control system  13000  may be configured to stop the articulation of the end effector  12208  upon reaching the articulation home state position, for example. In certain instances, the control system  13000  may be configured to provide feedback to the operator when the end effector  12208  reaches the articulation home state position, for example. 
     In certain instances, the control system  13000  may comprise various executable modules such as software, programs, data, drivers, and/or application program interfaces (APIs), for example.  FIG. 90  depicts an exemplary virtual detent module  10000  that can be stored in the memory  13010 , for example. The module  10000  may include program instructions, which when executed may cause the processer  13008 , for example, to alert the operator of the surgical instrument  12200  when the end effector  12208  reaches the articulation home state position during the articulation of the end effector  12208  from an articulated position, for example. 
     As described above, referring primarily to  FIGS. 89, 93, and 94 , the operator may use the rocker  13012  to articulate the end effector  12208 , for example. In certain instances, the operator may depress the dome switch  13004 A of the rocker  13012  to articulate the end effector  12208  in a first direction such as a clockwise direction to the right, for example, and may depress the dome switch  13004 B to articulate the end effector  12208  in a second direction such as a counterclockwise direction to the left, for example. In various instances, as illustrated in  FIG. 90 , the module  10000  may modulate the response of the processor  13008  to input signals from the dome switches  13004 A and/or  13004 B. For example, the processor  13008  can be configured to activate the motor  12216  to articulate the end effector  12208  to the right, for example, while the dome switch  13004 A is depressed; and the processor  13008  can be configured to activate the motor  12216  to articulate the end effector  12208  to the left, for example, while the dome switch  13004 B is depressed. In addition, the processor  13008  may be configured to stop the articulation of the end effector  12208  by causing the motor  12216  to stop, for example, when input signals from the dome switches  13004 A and/or  13004 B are stopped such as when the operator releases the dome switches  13004 A and/or  13004 B, respectively. 
     In various instances, as described above, the articulation home state position may comprise a range of positions. In certain instances, the processor  13008  can configured to detect when the end effector  12208  enters the range of positions defining the articulation home state position. In certain instances, the surgical instrument  12200  may comprise one or more positioning systems (not shown) for sensing and recording the articulation position of the end effector  12208 . The processor  13008  can be configured to employ the one or more positioning systems to detect when the end effector  12208  enters the articulation home state position. 
     As illustrated in  FIG. 90 , in certain instances, upon reaching the articulation home state position, the processor  13008  may stop the articulation of the end effector  12208  to alert the operator that the articulation home state position is reached; the processor  13008 , in certain instances, may stop the articulation in the articulation home state position even if the operator continues to depress the rocker  13012 . In certain instances, in order to continue past the articulation home state position, the operator may release the rocker  13012  and then tilt it again to restart the articulation. In at least one such instance, the operator may push the rocker  13012  to depress dome switch  13004 A, for example, to rotate the end effector  12208  toward its home state position until the end effector  12208  reaches its home state position and the processor  13008  stops the articulation of the end effector  12208 , wherein the operator can then release the rocker  13012  and, then, push the rocker  13012  to depress the dome switch  13004 A once again in order to continue the articulation of the end effector  12208  in the same direction. 
     In certain instances, as illustrated in  FIG. 91 , the module  10000  may comprise a feedback mechanism to alert the operator when the articulation home state position is reached. Various feedback devices  12248  ( FIG. 89 ) can be employed by the processor  13008  to provide sensory feedback to the operator. In certain instances, the devices  12248  may comprise, for example, visual feedback devices such as display screens and/or LED indicators, for example. In certain instances, the devices  12248  may comprise audio feedback devices such as speakers and/or buzzers, for example. In certain instances, the devices  12248  may comprise tactile feedback devices such as a mechanical detent, for example, which can provide haptic feedback, for example. In some instances, haptic feedback can be provided by a vibrating motor, for example, that can provide a pulse of vibrations to the handle of the surgical instrument, for example. In certain instances, the devices  12248  may comprise combinations of visual feedback devices, audio feedback devices, and/or tactile feedback devices, for example. 
     In certain instances, the processor  13008  can be configured to stop the articulation of the end effector  12208  and provide feedback to the operator when the articulation home state position is reached, for example. In certain instances, the processor  13008  may provide feedback to the operator but may not stop the articulation of the end effector  12208  when the articulation home state position is reached. In at least one instance, the end effector  12208  can be moved from a position on a first side of the home state position toward the home state position, pass through the home state position, and continue moving in the same direction on the other side of the home state position. During such movement, the operator may be supplied with some form of feedback at the moment the end effector  12208  passes through the home state position. In certain instances, the processor  13008  may stop the articulation of the end effector  12208  but may not provide feedback to the operator when the articulation home state position is reached, for example. In certain instances, the processor  13008  may pause the end effector  12208  as it passes through its center position and then continue past its center position. In at least one instance, the end effector  12208  can temporarily dwell in its center position for about 2 seconds, for example, and then continue its articulation so long as the articulation switch  13012  remains depressed. 
     In various instances, an operator of the surgical instrument  12200  may attempt to articulate the end effector  12208  back to its unarticulated position utilizing the rocker switch  13012 . As the reader will appreciate, the operator may not be able to accurately and/or repeatably align the end effector  12208  with the longitudinal axis of the surgical instrument shaft. In various instances, though, the operator can readily position the end effector  12208  within a certain range of the center position. For instance, an operator may push the rocker switch  13012  to rotate the end effector  12208  toward its center position and then release the rocker switch  13012  when the operator believes that the end effector  12208  has reached its center position or is close to its center position. The processor  13008  can interpret such circumstances as an attempt to recenter the end effector  12208  and, in the event that the end effector  12208  is not in its center position, the processor  13008  can automatically center the end effector  12208 . In at least one example, if the operator of the surgical instrument releases the rocker switch  13012  when the end effector  12208  is within about 10 degrees on either side of the center position, for example, the processor  13008  may automatically recenter the end effector  12208 . 
     In various instances, referring primarily to  FIGS. 89, 92, and 95 , the module  10000  may comprise an articulation resetting or centering mechanism. In certain instances, the control system  13000  may include a reset input which may reset or return the end effector  12208  to the articulation home state position if the end effector  12208  is in an articulated position. For example, upon receiving a reset input signal, the processor  13008  may determine the articulation position of the end effector  12208  and, if the end effector  12208  is in the articulation home state position, the processor  13008  may take no action to change the articulation position of the end effector  12208 . However, if the end effector  12208  is in an articulated position when the processor  13008  receives a reset input signal, the processor  13008  may activate the motor  12216  to return the end effector  12208  to the articulation home state position. As illustrated in  FIG. 95 , the operator may depress the rocker  13012  downward to close the dome switches  13004 A and  13004 B simultaneously, or at least within a short time period from each other, which may transmit the reset input signal to the processor  13008  to reset or return the end effector  12208  to the articulation home state position. The operator may then release the rocker  13012  to allow the rocker  13012  to return to the neutral position and the switches  13004 A and  13004 B to the open positions. Alternatively, the interface  13001  of the control system  13000  may include a separate reset switch such as, for example, another dome switch which can be independently closed by the operator to transmit the articulation reset input signal to the processor  13008 . 
     Referring again to  FIG. 87 , the end effector  12208  of the surgical instrument  12200  may include a first jaw comprising an anvil  10002  and a second jaw comprising a channel  10004  configured to receive a staple cartridge  10006  which may include a plurality of staples. In certain instances, the end effector  12208  can be transitioned between an open configuration and a closed configuration to capture tissue between the anvil  10002  and the staple cartridge  10006 , for example. Furthermore, the surgical instrument  12200  may include a firing member which can be moved axially between a firing home state position and a fired position to deploy the staples from the staple cartridge  10006  and/or cut the tissue captured between the anvil  10002  and the staple cartridge  10006  when the end effector  12208  is in the closed configuration. 
     As discussed above, the end effector  12208  can be transitioned between an open configuration and a closed configuration to clamp tissue therein. In at least one embodiment, the anvil  10002  can be moved between an open position and a closed position to compress tissue against the staple cartridge  10006 . In various instances, the pressure or force that the anvil  10002  can apply to the tissue may depend on the thickness of the tissue. For a given gap distance between the anvil  10002  and the staple cartridge  10006 , the anvil  10002  may apply a larger compressive pressure or force to thicker tissue than thinner tissue. The surgical instrument can include a sensor, such as a load cell, for example, which can detect the pressure or force being applied to the tissue. In certain instances, the thickness and/or composition of the tissue may change while pressure or force is being applied thereto. For instance, fluid, such as blood, for example, contained within the compressed tissue may flow outwardly into the adjacent tissue. In such circumstances, the tissue may become thinner and/or the compressive pressure or force applied to the tissue may be reduced. The sensor configured to detect the pressure of force being applied to the tissue may detect this change. The sensor can be in signal communication with the processor  13008  wherein the processor  13008  can monitor the pressure or force being applied to the tissue and/or the change in the pressure of force being applied to the tissue. In at least one instance, the processor  13008  can evaluate the change in the pressure or force and communicate to the operator of the surgical instrument when the pressure or force has reached a steady state condition and is no longer changing. The processor  13008  can also determine when the change in the pressure or force is at and/or below a threshold value, or rate. For instance, when the change in the pressure or force is above about 10 percent per second, the processor  13008  can illuminate a caution indicator associated with the firing actuator, for example, and when the change in the pressure or force is at or below about 10 percent per second, the processor can illuminate a ready-to-fire indicator associated with the firing actuator, for example. In some circumstances, the surgical instrument may prohibit the firing member from being advanced distally through the end effector  12208  until the change in pressure or force is at and/or below the threshold rate, for example. 
     In certain instances, the operator of the surgical instrument may elect to deploy only some of the staples stored within the end effector  12208 . After the firing member has been sufficiently advanced, in such circumstances, the firing member can be retracted. In various other instances, the operator of the surgical instrument may elect to deploy all of the staples stored within the end effector  12208 . In either event, the operator of the surgical instrument can depress a firing actuator extending from the handle assembly  12210  to actuate the motor  12216  and advance the firing member distally. The motor  12216  can be actuated once the firing actuator has been sufficiently depressed. In at least one mode of operation, further depression of the firing actuator may not affect the operation of the motor  12216 . The motor  12216  may be operated in the manner dictated by the processor  13008  until the firing actuator is released. In at least one other mode of operation, the degree or amount in which the firing actuator is depressed may affect the manner in which the motor  12216  is operated. For instance, an initial depression of the firing actuator can be detected by the processor  13008  and, in response thereto, the processor  13008  can operate the motor  12216  at a first speed, wherein additional depression of the firing actuator can be detected by the processor  13008  and, in response thereto, the processor  13008  can operate the motor  12216  at a second speed, such as a faster speed, for example. In certain instances, the change in the depression of the firing actuator can be proportional to the change in the motor speed. In at least one instance, the change in the depression of the firing actuator can be linearly proportional to the change in the motor speed. In various circumstances, the further the firing actuator is pulled, the faster the motor  12216  is operated. In certain embodiments, the amount of pressure or force applied to the firing actuator may affect the manner in which the motor  12216  is operated. For instance, an initial pressure or force applied to the firing actuator can be detected by the processor  13008  and, in response thereto, the processor  13008  can operate the motor  12216  at a first speed, wherein additional pressure or force applied to the firing actuator can be detected by the processor  13008  and, in response thereto, the processor  13008  can operate the motor  12216  at a second speed, such as a faster speed, for example. In certain instances, the change in the pressure or force applied to the firing actuator can be proportional to the change in the motor speed. In at least one instance, the change in the pressure or force applied to the firing actuator can be linearly proportional to the change in the motor speed. The disclosure of U.S. Pat. No. 7,845,537, entitled SURGICAL INSTRUMENT HAVING RECORDING CAPABILITIES, which issued on Dec. 7, 2010, is incorporated by reference in its entirety. 
     As discussed above, the operator of the surgical instrument may elect to deploy all of the staples stored within the end effector  12208 . In such circumstances, the operator may depress the firing actuator and then release the actuator when they believe that all of the staples have been deployed during a firing stroke of the firing member. In some instances, the surgical instrument can include an indicator which can be illuminated by the processor  13008  when the firing stroke has been completed. A suitable indicator can comprise a light emitting diode (LED), for example. In certain instances, the operator may believe that a firing stroke has been fully completed even though it may have only been nearly completed. The surgical instrument can comprise at least one sensor configured to detect the position of the firing member within its firing stroke wherein the sensor can be in signal communication with the processor  13008 . In the event that the firing stroke is ended at a nearly completed position, the processor  13008  can command the motor  12216  to finish the firing stroke of the firing member. For instance, if the firing member has completed all but the last 5 mm of the firing stroke, for example, the processor  13008  can assume that the operator meant to complete the firing stroke and automatically complete the firing stroke. 
     Referring again to  FIG. 87 , the interface  13001  of the surgical instrument  12200  may include a home state input  13014 . The operator may utilize the home state input to transmit a home state input signal to the processor  13008  to return the surgical instrument  12200  to home state which may include returning the end effector  12208  to the articulation home state position and/or the firing member to the firing home state position. As illustrated in  FIGS. 89 and 93 , the home state input  13014  may include a cap or a cover, for example, which can be depressed by the operator to close the switch  13004 C and transmit the home state input signal through the circuit  13006 C to the processor  13008 . In certain instances, the home state input  13014  can be configured to return the end effector  12208  to the articulation home state position, and a separate input can be utilized to return the firing member to the firing home state position. In certain instances, the home state input  13014  can be configured to return the firing member to the firing home state position, and a separate input can be utilized to return the end effector  12208  to the articulation home state position such as, for example, the rocker  13012 . 
     In various instances, the processor  13008  can be configured to cause the firing member to return to the firing home state position and the end effector  12208  to return to the articulation home state position upon receiving the home state input signal from the home state input  13014 . In certain instances, the response of the processor  13008  to the home state input signal may depend on whether the surgical instrument  12200  is in a firing mode or an articulation mode; if the processor  13008  determines that the surgical instrument  12200  is in the articulation mode, the processor  13008  may cause the end effector  12208  to return to the articulation home state position in response to the home state input signal, for example; and if the processor  13008  determines that the surgical instrument  12200  is in the firing mode, the processor  13008  may cause the firing member to return to the firing home state position in response to the home state input signal, for example. In certain instances, the firing member can be advanced axially to fire the staples from the staple cartridge  10006  only when the end effector  12208  is in the closed configuration. In such instances, the surgical instrument  12200  can be in the firing mode only when the end effector  12208  is in the closed configuration. In certain instances, the end effector  12208  can be articulated only when the end effector  12208  is in the open configuration. In such instances, the surgical instrument  12200  can be in the articulation mode only when the end effector  12208  is in the open configuration. Accordingly, in certain instances, the processor  13008  can be configured to determine whether the surgical instrument  12200  is in the articulation mode or the firing mode by determining whether the end effector  12208  is in the open configuration or the closed configuration. In certain instances, one or more sensors  13016  ( FIG. 89 ) can be employed by the processor  13008  to determine whether the end effector  12208  is in the open configuration or closed configuration. 
     Referring now to  FIGS. 87 and 96 , the surgical instrument  12200  may comprise a screen  12251  which may be included in the handle assembly  12202 , for example. The screen  12251  can be employed by one or more of the microcontrollers described herein to alert, guide, and/or provide feedback to the operator of the surgical instrument  12200 , for example. The screen  12251  can produce an output display  12250 . In use, the operator may tilt, flip, and/or rotate the handle assembly  12202 , for example, and, in response, the microcontroller can change the orientation of the output display  12250  to improve, align, and/or adjust the orientation of the output display  12250  with respect to the view of the operator of the surgical instrument  12200  and/or any suitable frame of reference, such as an inertial, or at least substantially inertial, frame of reference, for example. A fixed frame of reference can be defined, at least in part, by gravity. In some instances, the downward acceleration of Earth&#39;s gravity can be represented by the vector −g in  FIG. 96 . In certain instances, a processor, such as the processor  13008 , for example, may be configured to detect the changes in the position of the handle assembly  12202  with respect to the frame of reference and adopt one of a plurality of orientations of the screen  12251  in accordance with the relative position of the screen  12251  with respect to the frame of reference. 
     In certain instances, as illustrated in  FIG. 96 , the screen  12251  can be disposed on a top surface  10008  of the handle assembly  12202 . In various instances, the surface  10008  may extend in a first plane defined by coordinates X 1  and Y 1  of a first set of Cartesian coordinates representing the handle assembly  12202 . In various instances, the screen  12251  may be positioned within the first plane. In some instances, the screen  12251  may be positioned within a plane which extends parallel to the first plane and/or any suitable plane in a fixed relationship relative to the first plane. For the purposes of convenience herein, it will be assumed that the first set of Cartesian coordinates representing the handle assembly are aligned with the screen  12251  and, thus, referred to as a screen set of Cartesian coordinates. The output display  12250  can reside in a second plane defined by coordinates X 2  and Y 2  of a second, or display, set of Cartesian coordinates. In certain instances, as illustrated in  FIG. 96 , the first plane can be coplanar with the second plane, for example. Moreover, the first, or screen, set of Cartesian coordinates can be aligned with the second, or display, set of Cartesian coordinates, in at least some instances. For example, +X 1  can be aligned with or parallel to +X 2 , +Y 1  can be aligned with or parallel to +Y 2 , and +Z 1  can be aligned with or parallel to +Z 2 . Correspondingly, in such instances, −X 1  can be aligned with or parallel to −X 2 , −Y 1  can be aligned with or parallel to −Y 2 , and −Z 1  can be aligned with or parallel to −Z 2 . As will be described in greater detail below, the second, or display, set of Cartesian coordinates can be realigned with respect to the first, or screen, set of Cartesian coordinates in certain instances. In various instances, a certain arrangement of the display Cartesian coordinates can be preferred. For instance, a neutral position of the surgical instrument  12200  can coincide with the +Z 1  axis of the screen coordinates being aligned with the +g vector. As will be described in greater detail below, the processor  13008  can tolerate a certain amount of deviation between the screen coordinates at the reference frame without changing the alignment to the display coordinates; however, beyond a certain deviation between the screen coordinates at the reference frame, the processor can change the alignment of the display coordinates relative to the screen coordinates. 
     Referring to  FIGS. 97-98D , a module  10010  can be configured to change or alter the orientation of the output display  12250  between a plurality of orientations in response to the changes in the position of the handle assembly  12202  which can be monitored through input from one or more accelerometers (not shown) that can be housed within the handle assembly  12202 , for example. As discussed above, and as illustrated in  FIG. 98A , the output display  12250  may adopt a first orientation wherein the +X 2  and +Y 2  vectors of the display set of Cartesian coordinates are aligned, or at least substantially aligned, with the +X 1  and +Y 1  vectors, respectively, of the screen set of Cartesian coordinates when the surgical instrument is in its neutral position. In certain instances, as illustrated in  FIG. 98B , the output display  12250  may adopt a second orientation wherein the +Y 2  and +X 2  vectors of the display set of Cartesian coordinates are aligned, or at least substantially aligned, with the +Y 1  and −X 1  vectors, respectively, of the screen set of Cartesian coordinates, for example. In certain instances, as illustrated in  FIG. 98C , the output display  12250  may adopt a third orientation wherein the +X 2  and +Y 2  vectors of the display set of Cartesian coordinates are aligned, or at least substantially aligned, with the −X 1  and −Y 1  vectors, respectively, of the screen set of Cartesian coordinates, for example. In certain instances, as illustrated in  FIG. 98D , the output display  12250  may adopt a fourth orientation wherein the +X 2  and +Y 2  vectors of the second set of Cartesian coordinates are aligned, or at least substantially aligned, with the −Y 1  and +X 1  vectors, respectively, of the screen set of Cartesian coordinates, for example. Other orientations are possible. 
     Referring to  FIGS. 97-98D , the processor  13008  can be configured to toggle the orientation of the output display  12250  between a plurality of orientations including the first orientation, the second orientation, the third orientation, and/or the fourth orientation, for example, to accommodate changes in the position of the handle assembly  12202 , for example. In certain instances, the module  10010  may include a hysteresis control algorithm to prevent dithering of the orientation while toggling between the first, second, third, and/or fourth orientations, for example. A hysteresis control algorithm can produce a lag between an initial detection of an event that would result in a display orientation change and the processor command to change the display orientation. As such, the hysteresis control algorithm can ignore events which would result in a potentially transient orientation and optimally wait to reorient the display until a steady state, or sufficiently steady state, condition has been reached. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the first orientation when an angle between the +Z 1  vector of the Z 1  axis and the −g vector of the gravity axis g is less than or equal to a maximum angle, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the second orientation when an angle between the +X 1  vector of the X 1  axis and the +g vector of the gravity axis g is less than or equal to a maximum angle, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the third orientation when an angle between the +Y 1  vector of the Y 1  axis and the +g vector of the gravity g axis is less than or equal to a maximum angle, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the fourth orientation when an angle between the +X 1  vector of the X 1  axis and the −g vector of the gravity axis g is less than or equal to a maximum angle, for example. In certain instances, the maximum angle can be any angle selected from a range of about 0 degrees, for example, to about 10 degrees, for example. In certain instances, the maximum angle can be any angle selected from a range of about 0 degrees, for example, to about 5 degrees, for example. In certain instances, the maximum angle can be about 5 degrees, for example. The maximum angles described above are exemplary and are not intended to limit the scope of the present disclosure. 
     Referring to  FIGS. 97-98D , in certain instances, the processor  13008  can be configured to orient the output display  12250  in the first orientation when the +Z 1  vector of the Z 1  axis and the −g vector of the gravity axis g are aligned, or at least substantially aligned with each other, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the second orientation when the +X 1  vector of the X 1  axis and the +g vector of the gravity axis g are aligned, or at least substantially aligned with each other, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the third orientation when the +Y 1  vector of the Y 1  axis and the +g vector of the gravity g axis are aligned, or at least substantially aligned with each other, for example. In certain instances, the processor  13008  can be configured to orient the output display  12250  in the fourth orientation when the +X 1  vector of the X 1  axis and the −g vector of the gravity axis g are aligned, or at least substantially aligned with each other, for example. 
     Referring to  FIGS. 97-98D , in certain instances, the processor  13008  can be configured to rotate the output display  12250  from the first orientation to the second orientation if the handle  12212  is rotated clockwise about the longitudinal axis LL ( FIG. 87 ) by an angle selected from a range of about 80 degrees, for example, to about 100 degrees, for example. If the handle  12212  is rotated clockwise about the longitudinal axis LL by less than 80 degrees, the processor  13008  may not reorient the output display  12250 , in this example. In certain instances, the processor  13008  can be configured to rotate the display  12250  from the first orientation to the fourth orientation if the handle  12212  is rotated counterclockwise about the longitudinal axis LL by an angle selected from a range of about 80 degrees, for example, to about 100 degrees, for example. If the handle  12212  is rotated counterclockwise about the longitudinal axis LL by less than 80 degrees, the processor  13008  may not reorient the output display  12250 , in this example. 
     As described above, the operator may use the rocker  13012  to articulate the end effector  12208 , for example. In certain instances, the operator may move their finger in a first direction to tilt the rocker  13012  to depress the dome switch  13004 A to articulate the end effector  12208  in a clockwise direction to the right, for example; and the operator may move their finger in a second direction, opposite the first direction, to depress the dome switch  13004 B to articulate the end effector  12208  in a counterclockwise direction to the left, for example. 
     Depending on the position and/or orientation of the rocker  13012  with respect to the interface  13001  and/or the handle assembly  12202 , in certain instances, in a first or neutral position of the handle assembly  12202 , the first direction can be an upward direction, for example, and the second direction can be a downward direction, for example, as illustrated in  FIGS. 87 and 100A . In such instances, the operator of the surgical instrument  12200  may become accustomed to moving their finger up, for example, to articulate the end effector  12208  to the right, for example; and the operator may become accustomed to moving their finger down, for example, to articulate the end effector  12208  to the left, for example. In certain instances, however, the operator may change the position of the handle assembly  12202  to a second position such as an upside down position, for example, as illustrated in  FIG. 100B . In such instances, if the operator does not remember to reverse the direction of movement of their finger, the operator may unintentionally articulate the end effector  12208  in an opposite direction to the direction the operator intended. 
     Referring to  FIG. 99 , the surgical instrument  12200  may comprise a module  10012  which may allow the operator to maintain the directions of movement to which a surgeon may have become accustomed with respect to the operation of the surgical instrument  12200 . As discussed above, the processor  13008  can be configured to toggle between a plurality of configurations in response to changes in the position and/or orientation of the handle assembly  12202 , for example. In certain instances, as illustrated in  FIG. 99 , the processor  13008  can be configured to toggle between a first configuration of the interface  13001  associated with a first position and/or orientation of the handle assembly  12202 , and a second configuration of the interface  13001  associated with a second position and/or orientation of the handle assembly  12202 . 
     In certain instances, in the first configuration, the processor  13008  can be configured to command an articulation motor to articulate the end effector  12208  to the right when the dome switch  13004 A is depressed, for example, and the processor  13008  can be configured to command an articulation motor to articulate the end effector  12208  to the left when the dome switch  13004 B is depressed, for example. In the second configuration, the processor  3008  can command an articulation motor to articulate the end effector  12208  to the left when the dome switch  13004 A is depressed, for example, and the processor  13008  can command an articulation motor to articulate the end effector  12208  to the right when the dome switch  13004 B is depressed, for example. In various embodiments, a surgical instrument can comprise one motor to articulate the end effector  12208  in both directions while, in other embodiments, the surgical instrument can comprise a first motor configured to articulate the end effector  12208  in a first direction and a second motor configured to articulate the end effector  12208  in a second direction. 
     Referring to  FIGS. 99-100B , the processor  13008  can be configured to adopt the first configuration while the handle assembly  12202  is in the first position and/or orientation, for example, and adopt the second configuration while the handle assembly  12202  is in the second position and/or orientation, for example. In certain instances, the processor  13008  can be configured to detect the orientation and/or position of the handle assembly  12202  through input from one or more accelerometers (not shown) which can be housed within the handle assembly  12202 , for example. Such accelerometers, in various instances, can detect the orientation of the handle assembly  12202  with respect to gravity, i.e., up and/or down. 
     In certain instances, the processor  13008  can be configured to adopt the first configuration while an angle between a vector D ( FIG. 87 ) extending through the handle assembly  12202  and the gravity vector g is any angle in the range of about 0 degrees, for example, to about 100 degrees, for example. In certain instances, the processor  13008  can be configured to adopt the first configuration while the angle between the vector D and the gravity vector g is any angle in the range of about 0 degrees, for example, to about 90 degrees, for example. In certain instances, the processor  13008  can be configured to adopt the first configuration while the angle between the vector D and the gravity vector g is less than or equal to about 80 degrees, for example. 
     In certain instances, the processor  13008  can be configured to adopt the second configuration while the angle between the vector D and the gravity vector g is greater than or equal to about 80 degrees, for example. In certain instances, the processor  13008  can be configured to adopt the second configuration while the angle between the vector D and the gravity vector g is greater than or equal to about 90 degrees, for example. In certain instances, the processor  13008  can be configured to adopt the second configuration while the angle between the vector D and the gravity vector g is greater than or equal to about 100 degrees, for example. 
     The reader will appreciate that the described orientations and/or positions of the handle assembly  12202  and their corresponding configurations which are adopted by the processor  13008  are exemplary in nature and are not intended to limit the scope of the present disclosure. The processor  13008  can be configured to adopt various other configurations in connection with various other orientations and/or positions of the handle assembly  12202 . 
     Referring to  FIG. 101 , in certain instances, the surgical instrument  12200  can be controlled and/or operated, or at least partially controlled and/or operated, by input from an operator received through a display such as, for example, the display  12250 ; the display  12250  may comprise a touchscreen adapted to receive the input from the operator which can be in the form of one or more touch gestures. In various instances, the display  12250  may be coupled to a processor such as, for example, the processor  13008  which can be configured to cause the surgical instrument  12200  to perform various functions in response to the touch gestures provided by the operator. In certain instances, the display  12250  may comprise a capacitive touchscreen, a resistive touchscreen, or any suitable touchscreen, for example. 
     Referring again to  FIG. 101 , the display  12250  may comprise a plurality of icons which can be associated with a plurality of functions that can be performed by the surgical instrument  12200 . In certain instances, the processor  13008  can be configured to cause the surgical instrument  12200  to perform a function when an icon representing such function is selected, touched, and/or pressed by the operator of the surgical instrument  12200 . In certain instances, a memory such as, for example, the memory  13010  may comprise one or more modules for associating the plurality of icons with the plurality of functions. 
     In certain instances, as illustrated in  FIG. 101 , the display  12250  may include a firing icon  10014 , for example. The processor  13008  can be configured to detect a firing input signal when the operator touches and/or presses the firing icon  10014 . In response to the detection of the firing input signal, the processor  13008  can be configured to activate the motor  12216  to motivate a firing member of the surgical instrument  12200  to fire the staples from the staple cartridge  10006  and/or cut tissue captured between the anvil  10002  and the staple cartridge  10006 , for example. In certain instances, as illustrated in  FIG. 101 , the display  12250  may include an articulation icon  10016  for articulating the end effector  12208  in a first direction such as, for example, a clockwise direction, for example; the display  12250  may also include an articulation icon  10018  for articulating the end effector  12208  in a second direction such as, for example, a counterclockwise direction. The reader will appreciate that the display  12250  may comprise various other icons associated with various other functions that the processor  13008  may cause the surgical instrument  12200  to perform when such icons are selected, touched, and/or pressed by the operator of the surgical instrument  12200 , for example. 
     In certain instances, one or more of the icons of the display  12250  may comprise words, symbols, and/or images representing the function that can be performed by touching or pressing the icons, for example. In certain instances, the articulation icon  10016  may show an image of the end effector  12208  articulated in the clockwise direction. In certain instances, the articulation icon  10018  may show an image of the end effector  12208  articulated in the counterclockwise direction. In certain instances, the firing icon  10014  may show an image of the staples being fired from the staple cartridge  10006 . 
     Referring to  FIGS. 87 and 102 , the interface  13001  of the surgical instrument  12200  may comprise a plurality of operational controls such as, for example, a closure trigger  10020 , a rotation knob  10022 , the articulation rocker  13012 , and/or a firing input  13017  ( FIG. 103 ). In certain instances, various operational controls of the interface  13001  of the surgical instrument  12200  may serve, in addition to their operational functions, as navigational controls. In certain instances, the surgical instrument  12200  may comprise an operational mode and a navigational mode. In the operational mode, some or all of the controls of the surgical instrument  12200  may be configured to perform operational functions; and in the navigational mode, some or all of the controls of the surgical instrument  12200  may be configured to perform navigational functions. In various instances, the navigational functions performed by some or all of the controls of the surgical instrument  12200  can be related to, associated with, and/or connected to the operational functions performed by the controls. In other words, the operational functions performed by the controls of the surgical instrument  12200  may define the navigational functions performed by such controls. 
     Referring to  FIGS. 87 and 102 , in certain instances, a processor such as, for example, the processor  13008  can be configured to toggle between a primary interface configuration while the surgical instrument  12200  is in the operational mode and a secondary interface configuration while the surgical instrument  12200  is in the navigational mode; the processor  13008  can be configured to assign operational functions to some or all of the controls of the interface  13001  in the operational mode and assign navigational functions to such controls in the navigational mode, for example. In certain instances, the navigational functions of the controls in the secondary interface configuration are defined by the operational functions of the controls in the primary interface configuration, for example. 
     Referring to  FIG. 102 , in certain instances, the operator of the surgical instrument  12200  may activate the navigational mode by opening or activating a navigational menu  10024  in the display  12250 , for example. In certain instances, the surgical instrument  12200  may comprise a navigational mode button or a switch (not shown) for activating the navigational mode. In any event, the processor  13008  may switch the controls of the interface  13001  from the primary interface configuration to the secondary interface configuration upon receiving a navigational mode input signal. 
     As illustrated in  FIG. 102 , the navigational menu  10024  may comprise various selectable categories, menus, and/or folders and/or various subcategories, sub-menus, and/or subfolders. In certain instances, the navigational menu  10024  may comprise an articulation category, a firing category, a closure category, a battery category and/or, rotation category, for example. 
     In certain instances, the articulation rocker  13012  can be utilized to articulate the end effector  12208 , in the operational mode, as described above, and can be utilized to select the articulation category, and/or launch and/or navigate an articulation menu in the navigational mode, for example. In certain instances, the firing input  13017  ( FIG. 103 ) can be utilized to fire the staples, in the operational mode, as described above, and can be utilized to select the firing category, and/or launch and/or navigate a firing menu in the navigational mode, for example. In certain instances, the closure trigger  10020  can be utilized to transition the end effector  12208  between an open configuration and an approximated configuration in the operational mode, as described above, and can be utilized to select the closure category, and/or launch and/or navigate a closure menu in the navigational mode, for example. In certain instances, the rotation knob  10022  can be utilized to rotate the end effector  12208  relative to the elongate shaft  12204  in the operational mode, and can be utilized to select the rotation category, and/or launch and/or navigate a rotation menu in the navigational mode, for example. 
     Referring primarily to  FIGS. 87 and 103 , the operation of the surgical instrument  12200  may involve a series or a sequence of steps, actions, events, and/or combinations thereof. In various circumstances, as illustrated in  FIG. 103 , the surgical instrument  12200  may include an indicator system  10030  which can be configured to guide, alert, and/or provide feedback to the operator of the surgical instrument  12200  with respect to the various steps, actions, and/or events. 
     In various instances, the indicator system  10030  may include a plurality of indicators  10032 . In certain instances, the indicators  10032  may comprise, for example, visual indicators such as a display screens, backlights, and/or LEDs, for example. In certain instances, the indicators  10032  may comprise audio indicators such as speakers and/or buzzers, for example. In certain instances, the indicators  10032  may comprise tactile indicators such as haptic actuators, for example. In certain instances, the indicators  10032  may comprise combinations of visual indicators, audio indicators, and/or tactile indicators, for example. 
     Referring to  FIG. 103 , the indicator system  10030  may include one or more microcontrollers such as, for example, the microcontroller  13002  which may comprise one or more processors such as, for example, the processor  13008  and/or one or more memory units such as, fore example, the memory  13010 . In various instances, the processor  13008  may be coupled to various sensors  10035  and/or feedback systems which may be configured to provide feedback to the processor  13008  regarding the status of the surgical instrument  12200  and/or the progress of the steps, actions, and/or events pertaining to the operation of the surgical instrument  12200 , for example. 
     In various instances, the operation of the surgical instrument  12200  may include various steps including an articulation step, a closure step, a firing step, a firing reset step, a closure reset step, an articulation reset step, and/or combinations thereof, for example. In various instances, the articulation step may involve articulating the end effector  12208  relative to the elongate shaft  12204  to an articulated position, for example; and the articulation reset step may involve returning the end effector  12208  to an articulation home state position, for example. In various instances, the closure step may involve transitioning the end effector  12208  to a closed configuration, for example; and the closure reset step may involve transitioning the end effector  12208  to an open configuration, for example. In various instances, the firing step may involve advancing a firing member to deploy staples from the staple cartridge  10006  and/or cut tissue captured by the end effector  12208 , for example. In various instances, the firing reset step may involve retraction of the firing member to a firing home state position, for example. 
     Referring to  FIG. 103 , one or more of the indicators  10032  of the indicator system  10030  can be associated with one or more of the various steps performed in connection with the operation of the surgical instrument  12200 . In various instances, as illustrated in  FIG. 103 , the indicators  10032  may include a bailout indicator  10033  associated with the bailout assembly  12228 , an articulation indicator  10034  associated with the articulation step, a closure indicator  10036  associated with the closure step, a firing indicator  10038  associated with the firing step, an articulation reset indicator  10040  associated with the articulation reset step, a closure reset indicator  10042  associated with the closure reset step, and/or a firing reset indicator  10044  associated with the firing reset step, for example. The reader will appreciate that the above described steps and/or indicators are exemplary in nature and are not intended to limit the scope of the present disclosure. Various other steps and/or indicators are contemplated by the present disclosure. 
     Referring to  FIG. 87 , in various instances, one or more of the controls of the interface  13001  can be employed in one or more of the steps of operation of the surgical instrument  12200 . In certain instances, the closure trigger  10020  can be employed in the closure step, for example. In certain instance, the firing input  13017  ( FIG. 103 ) can be employed in the firing step, for example. In certain instances, the articulation rocker  13012  can be employed in the articulation step and/or the articulation reset step, for example. In certain instances, the home state input  13014  can be employed in the firing reset step, for example. 
     Referring to  FIG. 103 , in various instances, the indicators  10032  associated with one of the steps of operation of the surgical instrument  10030  may also be associated with the controls employed in such steps. For example, the articulation indicator  10034  can be associated with the articulation rocker  13012 , the closure indicator  10036  can be associated with the closure trigger  10020 , the firing indicator  10038  can be associated with the firing input  13017 , and/or the firing reset indicator  10044  can be associated with the home state input  13014 . In certain instances, associating an indicator with a control of the interface  13001  may include placing or positioning the indicator on, within, partially within, near, and/or in close proximity to the control, for example, to aid the operator in associating the indicator with the control. The reader will appreciate that the above described controls and/or the indicators associated with such controls are exemplary in nature and are not intended to limit the scope of the present disclosure. Various other controls and the indicators associated with such controls are contemplated by the present disclosure. 
     In various instances, the processor  13008  can be configured to activate the indicators  10032  in one or more sequences defined by the order of the steps associated with the indicators  10032 . For example, the operator may need to operate the surgical instrument  12200  in a series of steps starting with the articulation step followed by the closure step, and further followed by the firing step. In such example, the processor  13008  can be configured to guide the operator through the sequence of steps by activating the corresponding articulation indicator  10034 , closure indicator  10036 , and firing indicator  10038  in the same order as the order of the steps. In other words, the processor  13008  can be configured to first activate the articulation indicator  10034  followed by the closure indicator  10036 , and further followed by the firing indicator  10038 , for example. In certain instances, the surgical instrument  12200  may comprise a bypass switch (not shown) which may be configured to allow the operator to bypass a step that is recommended but not required, for example. In such instances, pressing the bypass switch may signal the processor  13008  to activate the next indicator in the sequence. 
     In various instances, the processor  13008  can be configured to toggle the indicators  10032  between a plurality of indicator configurations to guide, alert, and/or provide feedback to the operator of the surgical instrument  12200 . In various instances, the processor  13008  may provide visual cues to the operator of the surgical instrument  12200  by the toggling of the indicators  10032  between the plurality of indicator configurations which may include activated and/or deactivated configurations, for example. In certain instances, one or more of the indicators  10032  may comprise a light source which can be activated in a first indicator configuration, for example, to alert the operator to perform a step associated with the indicators  10032 , for example; and the light source can be deactivated in a second indicator configuration, for example, to alert the operator when the step is completed, for example. 
     In certain instances, the light source can be a blinking light which can be transitioned by the processor  13008  between a blinking configuration and a non-blinking configuration. In certain instances, the blinking light, in the non-blinking configuration, may be transitioned to solid illumination or turned off, for example. In certain instances, the blinking light, in the blinking configuration, may represent a waiting period while a step is in progress, for example. In certain instances, the blinking frequency of the blinking light may be changed to provide various visual cues. For example, the blinking frequency of the blinking light that represents a waiting period may be increased or decreased as the waiting period approaches its completion. The reader will appreciate that the waiting period can be a forced waiting period and/or a recommended waiting period, for example. In certain instances, forced waiting periods can be represented by a blinking configuration different from recommended waiting periods. In certain instances, the blinking light may comprise a first color representing a forced waiting period and a second color representing a recommended waiting period, wherein the first color is different from the second color. In certain instances, the first color can be a red color, for example, and the second color can be a yellow color, for example. 
     In various instances, one or more of the indicators  10032  can be toggled by the processor  13008  between a first indicator configuration representing controls that are available for use in a standard next step of the steps of operation of the surgical instrument  12200 , a second indicator configuration representing controls that are available for use in a non-standard next step of the steps of operation of the surgical instrument  12200 , and/or a third indicator configuration representing controls that are not available for use in a next step of the steps of operation of the surgical instrument  12200 , for example. For instance, when the end effector  12208  of the surgical instrument  12000  is in an open configuration, the articulation indicator  10034  and the closure indicator  10036  can be illuminated indicating to the operator of the surgical instrument  12200  that those two functions, i.e., end effector articulation and end effector closure, are available to the operator at that moment. In such a state, the firing indicator  10038  may not be illuminated indicating to the operator that the firing function is not available to the operator at that moment. Once the end effector  12208  has been placed in a closed and/or clamped configuration, the articulation indicator  10034  may be deilluminated indicating to the operator that the articulation function is no longer available at that moment. In such a state, the illumination of the closure indicator  10036  may be reduced indicating to the operator that the closing function can be reversed at that moment. Moreover, in such a state, the firing indicator  10038  can become illuminated indicating to the operator that the firing function is available to the operator at that moment. Once the firing member has been at least partially advanced, the closure indicator  10036  may be deilluminated indicating that the closing function cannot be reversed at that moment. When the firing member is retracted back to its unfired position, the illumination of the firing indicator  10038  may be reduced indicating to the operator that the firing member can be readvanced, if needed. Alternatively, once the firing member has been retracted, the firing indicator  10038  may be deilluminated indicating to the operator that the firing member cannot be readvanced at that moment. In either event, the closure indicator  10036  can be reilluminated after the firing member has been retracted back to its unfired position indicating to the operator that the closing function can be reversed at that moment. The articulation indicator  10034  may remain deilluminated indicating that the articulation function is not available at that moment. Once the end effector  12208  has been opened, the firing indicator  10038  can be deilluminated, if it hadn&#39;t been deilluminated already, indicating to the operator that the firing function is not available at that moment, the closing indicator  10036  can remain illuminated or its illumination can be reduced indicating to the operator that the closing function is still available at that moment, and the articulation indicator  10034  can be reilluminated indicating to the operator that the articulation function is available at that moment. The example provided above is exemplary and other embodiments are possible. 
     In certain instances, the one or more of the indicators  10032  may include a light source that can be toggled by the processor  13008  between a first color in the first indicator configuration, a second color in the second indicator configuration, and/or a third color in the third indicator configuration, for example. In certain instances, the indicators  10032  can be toggled by the processor  13008  between the first indicator configuration, the second indicator configuration, and/or the third indicator configuration by changing the light intensity of the light source or scanning through the color spectrum, for example. In certain instances, the first indicator configuration may comprise a first light intensity, for example, the second indicator configuration may comprise a second light intensity, for example, and/or the third indicator configuration may comprise a third indicator configuration, for example. 
     In various instances, in the firing step of operation of the surgical instrument  12200 , the firing member can be motivated to deploy the plurality of staples from the staple cartridge  10006  into tissue captured between the anvil  10002  and the staple cartridge  10006 , and advance a cutting member (not shown) to cut the captured tissue. The reader will appreciate that advancing the cutting member to cut the captured tissue in the absence of a staple cartridge or in the presence of a spent staple cartridge may be undesirable. Accordingly, in various instances, the surgical instrument  12200  may comprise a lockout mechanism (not shown) which can be activated to prevent advancement of the cutting member in the absence of a staple cartridge or in the presence of a spent staple cartridge, for example. 
     Referring to  FIG. 104 , a module  10046  can be employed by an indicator system such as, for example, the indicator system  10030  ( FIG. 103 ). In various instances, the module  10046  may comprise program instructions stored in one or more memory units such as, for example, the memory  13010 , which when executed may cause the processor  13008  to employ the indicators  10032  to alert, guide, and/or provide feedback to the operator of the surgical instrument  12200  during the firing step of operation of the surgical instrument  12200 , for example. In certain instances, one or more of the indicators  10032  such as the firing indicator  10038  and/or the firing reset indicator  10044 , for example, can be toggled by the processor  13008  between the first indicator configuration, the second indicator configuration, and/or the third indicator configuration to alert, guide, and/or provide feedback to the operator of the surgical instrument  12200  during the firing step of operation of the surgical instrument  12200 , for example. 
     Referring to  FIGS. 103 and 104 , the operator of the surgical instrument  12200  may actuate the firing input  13017  to cause the processor  13008  to activate the motor  12216 , for example, to motivate the firing member to deploy the plurality of staples from the staple cartridge  10006  into the captured tissue and advance the cutting member to cut the captured tissue. In certain instances, the firing indicator  10038  can be set to the first indicator configuration to alert the operator that the firing input  13017  is available for use and/or is one of the standard control options available for completion of the firing step. 
     In certain instances, as illustrated in  FIGS. 103 and 104 , if the processor  13008  detects that the lockout mechanism is active, the processor  13008  may stop the advancement of the cutting member by stopping and/or deactivating the motor  12216 , for example. In addition, the processor  13008  can be configured to transition the firing indicator  10038  from the first indicator configuration to the third indicator configuration to caution the operator that the firing input  13017  is not available for use. In certain instances, the processor  13008  may also be configured to illuminate the display  12250  and display an image of a missing staple cartridge, for example. In certain instances, the processor  13008  may also set the firing reset indicator  10044  to the first indicator configuration, for example, to inform the operator that home state input  13014  is available for use to motivate the firing member to retract the cutting member to the firing home state position, for example. In certain instances, the processor  13008  can be configured to detect the installation of a new staple cartridge, through the sensors  10035  for example, and in response, return the firing indicator  10038  to the first indicator configuration, for example. 
     In certain instances, as illustrated in  FIG. 104 , if the operator releases the firing input  13017  before completion of the firing step, the processor  13008  can be configured to stop the motor  12216 . In certain instances, the processor  13008  may also maintain the firing indicator  10038  in the first indicator configuration, for example, to alert the operator that the firing input  13017  is available for use as the standard control option available for completion of the firing step of operation of the surgical instrument  12200 , for example. In certain instances, the processor  13008  may also set the firing reset indicator  10044  to the second indicator configuration, for example, to inform the operator that home state input  13014  is available for use as a non-standard control option available for use to retract the cutting member to the firing home state position, for example, if the operator decides to abort the firing step of operation of the surgical instrument  12200 , for example. 
     Further to the above, as illustrated in  FIG. 104 , if the firing input  13017  is re-actuated by the operator, the processor  13008  may, in response, reactivate the motor  12216  to continue advancing the cutting member until the cutting member is fully advanced. In certain instances, the processor  13008  may employ the sensors  10035  to detect when the cutting member is fully advanced; the processor  13008  may then reverse the direction of rotation of the motor  12216 , for example, to motivate the firing member to retract the cutting member to the firing home state position, for example. In certain instances, the processor  13008  can be configured to stop the motor  12216 , for example, and/or set the closure reset indicator  10042  to the first indicator configuration, for example, if the processor detects that the cutting member has reached the firing home state position, for example. 
     As described herein, a surgical instrument can enter into various operational states, modes, and/or configurations. In certain instances, the instrument may enter into an operational state, mode, and/or configuration that is undesired by the operator who may be unsure as to how to remove the instrument from that undesired state, mode, and/or configuration. In at least one instance, the surgical instrument can include a reset button which, when actuated, can place the instrument in a default state, mode, and/or configuration. For instance, the default state, mode, and/or configuration can comprise an operational mode, and not a navigational mode. In at least one instance, the default state and/or configuration can comprise a certain orientation of the display output  12250 , for example. The reset button can be in signal communication with the processor  13008  which can place the surgical instrument in the default state, mode, and/or configuration. In certain instances, the processor  13008  can be configured to hold the surgical instrument in the default state, mode, and/or configuration. In at least one instance, the surgical instrument can include a lock button which, when actuated, can lock the surgical instrument in its default state, mode, and/or configuration. In certain instance, a lock button can lock the surgical instrument in its current state, mode, and/or configuration. The operational state, mode, and/or configuration can be unlocked by actuating the lock button once again. In various embodiments, the surgical instrument can include at least one accelerometer in signal communication with the processor  13008  which can determine when the instrument handle is being shaken or being moved back and forth quickly. When such shaking is sensed, the processor  13008  can place the surgical instrument into a default operation state, mode, and/or configuration. 
     Referring to  FIG. 105 , in various instances, a surgical assembly  10050  may include a surgical instrument such as, for example, the surgical instrument  12200  and a remote operating unit  10052 . In certain instances, the surgical instrument  12200  may comprise a primary interface such as, for example, the interface  13001  which may reside in the handle assembly  12202 , as illustrated in  FIG. 87 . In certain instances, the interface  13001  may include a plurality of primary controls such as, for example, the closure trigger  10020  ( FIG. 87 ), the rotation knob  10022 , the articulation rocker  13012 , the home state input  13014 , and/or the firing input  13017  ( FIG. 103 ). 
     In various instances, an operator of the surgical instrument  12200  may manually operate the primary controls of the interface  13001  to perform a surgical procedure, for example. As described above, the operator may actuate the articulation rocker  13012  to activate the motor  12216  to articulate the end effector  12208  between an unarticulated position and an articulated position, for example. In certain instances, the operator may actuate the closure trigger  10020  to transition the end effector  12208  between an open configuration and a closed configuration, for example. In certain instances, the operator may actuate the firing input  13017  to activate the motor  12216  to motivate the firing member of the surgical instrument  12200  to fire the staples from the staple cartridge  10006  and/or cut tissue captured between the anvil  10002  and the staple cartridge  10006 , for example. 
     In various instances, the operator of the surgical instrument  12200  may not be sufficiently close in proximity to the handle assembly  12202  to be able to manually operate the interface  13001 . For example, the operator may operate the surgical instrument  12200  together with a robotically-controlled surgical system, which may be controlled from a remote location. In such instances, the operator may need to operate the surgical instrument  12200  from the remote location where the operator operates the robotically-controlled surgical system, for example; the operator may employ the remote operating unit  10052  to operate the surgical instrument  12200  remotely, for example. Various robotic systems, instruments, components, and methods are disclosed in U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535, which is incorporated by reference herein in its entirety. 
     Referring to  FIGS. 105 and 106 , the remote operating unit  10052  may include a secondary interface  13001 ′, a display  12250 ′, and/or a power assembly  12206 ′ (or “power source” or “power pack”), for example. In various instances, the secondary interface  13001 ′ may include a plurality of secondary controls which may correspond to the primary controls of the primary interface  13001 ′. In certain instances, the remote operating unit  10052  may include a remote articulation rocker  13012 ′ corresponding to the articulation rocker  13012 , for example. In certain instances, the remote operating unit  10052  may include a remote firing input  13017 ′ corresponding to the firing input  13017  of the surgical instrument  12200 , for example. In certain instances, the remote operating unit  10052  may include a remote home state input  13014 ′ corresponding to the home state input  13014  of the surgical instrument  12200 , for example. 
     In certain instances, as illustrated in  FIG. 105 , the remote operating unit  10052 , the interface  13001 ′, and/or the plurality of secondary controls may comprise a different shape and/or design from the handle assembly  12202 , the interface  13001 , and/or the plurality of primary controls, respectively. In certain instances, as illustrated in  FIG. 106 , the remote operating unit  10052 , the interface  13001 ′, and/or the plurality of secondary controls may comprise the same, or at least substantially the same, shape and/or design to the handle assembly  12202 , the interface  13001 , and/or the plurality of primary controls, respectively. 
     In various instances, as illustrated in  FIGS. 105 and 106 , the remote operating unit  10052  can be coupled to the handle assembly  12202  of the surgical instrument  12200  via an elongate flexible cable  10054 , for example, which can be configured to transmit various actuation signals to the processor  13008  of the surgical instrument  12200 , for example; the various actuation signals can be generated by actuating the plurality of secondary controls of the interface  13001 ′, for example. In certain instances, as illustrated in  FIG. 107 , the remote operating unit  10052  may comprise a transmitter  10056  which can be configured to wirelessly transmit the actuation signals generated by the secondary controls of the secondary interface  13001 ′ from the remote operating unit  10052  to the processor  13001 , for example, through a receiver  10058  which can be located in the handle assembly  12202 , for example. 
     In various instances, the surgical instrument  12200  and/or the remote operating unit  10052  may include communication activation inputs (not shown). In certain instances, actuating the communication activation inputs may be a precursory step to establishing communication between the surgical instrument  12200  and the remote operating unit  10052 , for example; once communication is established, the operator may employ the remote operating unit  10052  to remotely control the surgical instrument  12200 , for example. 
     In various instances, the memory  13010  may include program instructions for a puppet mode, which when executed may cause the processor  13008  to respond to the actuation signals generated by the plurality of secondary controls of the secondary interface  13001 ′ in the same, or at least similar, manner to the response of the processor  13008  to the actuation signals generated by the plurality of primary controls of the primary interface  13001 . In other words, the responses of the processor  13008  to the actuation signals generated by the plurality of secondary controls can be configured to mimic the responses of the processor  13008  to the actuation signals generated by the plurality of primary controls, for example. 
     In certain instances, actuation of the remote firing input  13017 ′ may solicit the same, or at least a similar, response from the processor  13008  as the actuation of the firing input  13017 ; the solicited response may include activation of the motor  12216  to motivate the firing member to fire the staples from the staple cartridge  10006  and/or cut tissue captured between the anvil  10002  and the staple cartridge  10006 , for example. In certain instances, actuation of the remote articulation rocker  13012 ′ may solicit the same, or at least a similar, response from the processor  13008  as the actuation of the articulation rocker  13012 ; the solicited response may include activation of the motor  12216  to articulate the end effector  12208  relative to the elongate shaft  12204 , for example. 
     In certain instances, the processor  13008  can be configured to require input actuation signals from both of the primary controls of the primary interface  13001  and the corresponding secondary controls of the secondary interface  13001 ′ to perform the function solicited by such controls. In such instances, the remote operator of the remote operating unit  10052  may need the assistance of an additional operator who can be employed to manually actuate the primary controls of the primary interface  13001  while the remote operator actuates the secondary controls of the secondary interface  13001 ′, for example. 
     In various instances, as described above, an operator may operate the surgical instrument  12200  together with a robotically-controlled surgical system, which may be controlled by a robotic control system from a remote location. In certain instances, the remote operating unit  10052  can be configured to work in tandem with the robotic control system. In certain instances, the robotic control system may include one or more control ports; and the remote operating unit  10052  may comprise connection means for coupling engagement with the control ports of the robotic control system. In such instances, the operator may operate the surgical instrument  12200  through an interface of the robotic control system, for example. In various instances, the control ports may comprise unique mechanical and/or electrical configurations which may require the use of original equipment manufacturer components to ensure consistent product quality and performance, for example. 
     In various instances, the remote operating unit  10052  may include various indicators  10032 ′ which can be similar in many respects to the indicators  10032  of the handle assembly  12202 . In certain instances, the indicators  10032 ′ of the remote operating unit  10052  can be employed by the processor  13008  in the same, or at least substantially the same, manner as the indicators  10032  to guide, alert, and/or provide feedback to the operator with respect to the various steps of operation of the surgical instrument  12200 . 
     In various instances, the remote operating unit  10052  may include various feedback devices  12248 ′ which can be similar in many respects to the feedback devices  12248  of the handle assembly  12202 . In certain instances, the feedback devices  12248 ′ of the remote operating unit  10052  can be employed by the processor  13008  in the same, or at least substantially the same, manner as the feedback devices  12248  to provide sensory feedback to the operator with respect to the various steps of operation of the surgical instrument  12200 . Similar to the feedback devices  12248 , the feedback devices  12248 ′ may include, for example, visual feedback devices, audio feedback devices, tactile feedback devices, and/or combinations thereof. 
     In various instances, as illustrated in  FIG. 108 , the remote operating unit  10052  can be included or integrated with a first surgical instrument  10060  and can be utilized to operate a second surgical instrument  10062 , for example. In certain instances, the first surgical instrument  10060  can reside in a surgical field  10065  and can be manually operated by the operator from within the surgical field  10065 , for example; and the second surgical instrument  10062  can reside outside the surgical field  10065 . In certain instances, to avoid exiting the surgical field  10065 , the operator may use the remote operating unit  10052  to remotely operate the second surgical instrument  10062  from within the surgical field  10065 , for example. In certain instances, the second surgical instrument  10062  may be a circular stapler, for example. The entire disclosure of U.S. Pat. No. 8,360,297, entitled SURGICAL CUTTING AND STAPLING INSTRUMENT WITH SELF ADJUSTING ANVIL, which issued on Jan. 29, 2013, is incorporated by reference herein. 
     In various instances, the first surgical instrument  10060  and/or the second surgical instrument  10062  may include communication activation inputs (not shown). In such instances, actuating the communication activation inputs may be a precursory step to establishing communication between the first surgical instrument  10060  and the second surgical instrument  10062 , for example; once communication is established, the operator may employ the remote operating unit  10052  to remotely control the second surgical instrument  10062 , for example. 
     In various instances, a surgical system can include modular components that can be attached and/or combined together to form a surgical instrument. In certain instances, the modular components can be designed, manufactured, programmed, and/or updated at different times and/or in accordance with different software and/or firmware revisions and updates. For example, referring primarily to  FIGS. 109 and 110 , a surgical instrument  14100  can include a first modular component  14110 , such as a handle, for example, and a second modular component  14120 , such as a shaft  14122  and an end effector  14124 , for example, which are described in greater detail herein. In various circumstances, the first modular component  14110  and the second modular component  14120  can be assembled together to form the modular surgical instrument  14100  or at least a portion thereof. Optionally, a different modular component may be coupled to the first modular component  14110 , such as shaft having different dimensions and/or features than those of the second modular component  14120 , for example. In various instances, the surgical instrument can include additional modular components, such as a modular battery, for example. Components of the modular surgical instrument  14100  can include a control system that is designed and configured to control various elements and/or functions of the surgical instrument  14100 . For example, the first modular component  14110  and the second modular component  14120  can each comprise a control system, and the control systems of each modular component  14110 ,  14120  can communicate and/or cooperate. In various instances, the first modular component  14110  may have been designed, manufactured, programmed, and/or updated at a different time and/or with different software and/or firmware than the second modular component  14120 , for example. 
     Referring now to  FIG. 111 , the assembled surgical system can include a first control system  14150 ′ and a second control system  14150 . The control systems  14150 ′,  14150  can be in signal communication, for example. In various instances, the second modular component  14120  can comprise the control system  14150 , for example, which can include a plurality of control modules  14152 . The control modules  14152  can affect a surgical function with and/or by an element or subsystem of the surgical instrument  14100 , for example. The control modules  14152  can affect a surgical function based on a pre-programmed routine, operator input, and/or system feedback, for example. In various instances, the first modular component  14110  can also comprise a control system  14150 ′, for example, which can include a plurality of control modules  14152 ′. The control system  14150 ′ and/or one of the control modules  14152 ′ of the first modular component  14110  may be different than the control system  14150  and/or one of the control modules  14152  of the second modular component  14120 . Though the control systems  14150  and  14150 ′ can be different, the control systems  14150  and  14150 ′ can be configured to control corresponding functions. For example, the control module  14152 ( a ) and the control module  14152 ( a )′ can both issue commands to firmware modules  14158  to implement a firing stroke, for example. In various instances, one of the control systems  14150 ,  14150 ′ and/or a control module  14152 ,  14152 ′ thereof may include updated software and/or firmware and/or can have a more-recent effective date, as described in greater detail herein. 
     A control module  14152 ,  14152 ′ can comprise software, firmware, a program, a module, and/or a routine, for example, and/or can include multiple software, firmware, programs, control modules, and/or routines, for example. In various circumstances, the control systems  14150 ,  14150 ′ can include multiple tiers and/or levels of command. For example, the control system  14150  can include a first tier  14144  of control modules  14152 , a second tier  14146  of control modules  14152 , and/or a third tier  14148  of control modules  14152 . Control modules  14152  of the first tier  14144  can be configured to issue commands to the control modules  14152  of the second tier  14146 , for example, and the control modules  14152  of the second tier  14146  can be configured to issue commands to the control modules  14152  of the third tier  14148 . In various instances, the control systems  14150 ,  14150 ′ can include less than three tiers and/or more than three tiers, for example. 
     Referring still to  FIG. 111 , the control module(s)  14152  in the first tier  14144  can comprise high-level software, or a clinical algorithm  14154 . The clinical algorithm  14154  can control the high-level functions of the surgical instrument  14100 , for example. In certain instances, the control module(s)  14152  in the second tier  14146  can comprise intermediate software, or framework module(s)  14156 , which can control the intermediate-level functions of the surgical instrument  14100 , for example. In certain instances, the clinical algorithm  14154  of the first tier  14144  can issue abstract commands to the framework module(s)  14156  of the second tier  14146  to control the surgical instrument  14100 . Furthermore, the control modules  14152  in the third tier  14148  can comprise firmware modules  14158 , for example, which can be specific to a particular hardware component  14160 , or components, of the surgical instrument  14100 . For example, the firmware modules  14158  can correspond to a particular cutting element, firing bar, trigger, sensor, and/or motor of the surgical instrument  14100 , and/or can correspond to a particular subsystem of the surgical instrument  14100 , for example. In various instances, a framework module  14156  can issue commands to a firmware module  14158  to implement a surgical function with the corresponding hardware component  14160 . Accordingly, the various control modules  14152  of the surgical system  14100  can communicate and/or cooperate during a surgical procedure. 
     Referring still to  FIG. 111 , the control system  14150  of the second component  14120  can correspond to the control system  14150 ′ of the first component  14110 , and the various control modules  14152  of the second component  14120  can correspond to the control modules  14152 ′ of the first component  14110 . Stated differently, each control module  14152  can include a parallel, or corresponding control module  14152 ′, and both control modules  14152  and  14152 ′ can be configured to perform identical, similar and/or related functions and/or to provide identical, similar and/or related commands. Referring still to  FIG. 111 , the control module  14152   a  can correspond to the control module  14152   a ′. For example, the control modules  14152   a  and  14152   a ′ can both control the firing stroke of a cutting element; however, control module  14152   a  can be configured to control a first cutting element design or model number and control module  14152   a ′ can be configured to control a different cutting element design or model number, for example. In other instances, the control module  14152   a ′ can comprise a software program and control module  14152   a  can comprise an updated or revised version of the software program, for example. 
     In various instances, the first component  14110  of the surgical instrument  14100  can include a clinical algorithm  14154 ′ that is different than the clinical algorithm  14154  of the second component  14120 . Additionally and/or alternatively, the first component  14110  can include a framework module  14156 ′ that is different than a corresponding framework module  14156  of the second component  14120 , and/or the first component  14110  can include a firmware module  14158 ′ that is different than a corresponding firmware module  14158  of the second component  14120 . 
     In various instances, corresponding control modules  14152 ,  14152 ′ can comprise different effective dates. A person having ordinary skill in the art will appreciate that the effective date of a control module  14152 ,  14152 ′ can correspond to a date that the control module  14152 ,  14152 ′ was designed, created, programmed, and/or updated, for example. The effective date of a control module can be recorded or stored in the program code of the control module, for example. In certain instances, a control module of the surgical instrument  14100  can be outdated. Furthermore, an out-of-date, or less-recently updated, control module may be incompatible with, disjointed from, and/or disconnected from an up-to-date and/or more-recently updated, control module. Accordingly, in certain instances, it may be desirable to update out-of-date control modules to ensure proper and effective operation of the surgical instrument  14100 . 
     In various instances, a modular component of the surgical system can include a predetermined default, or master, control system. In such instances, if the control systems of the assembled modular components are different, the default control system can update, overwrite, revise, and/or replace the non-default control systems. In other words, if corresponding control modules are different, incompatible, or inconsistent, for example, the non-default control module can be updated and the default control module can be preserved. For example, if the handle  14110  comprises the control system  14150 ′, which is the non-default control system, and the shaft  14120  comprises the control system  14150 , which is the master control system, the control system  14150 ′ of the handle  14110  can be updated based on the control system  14150  of the shaft  14120 . 
     It may be desirable to program a shaft component  14120  of the surgical instrument to include the default control system in circumstances where shaft components are more frequently updated and/or modified than handle components. For example, if new generations and/or iterations of shaft components  14120  are introduced more frequently than new generations and/or iterations of handle components  14110 , it may be advantageous to include a default, or master, control system in the shaft component  14120  of the modular surgical instrument  14100 . Various circumstances described throughout the present disclosure relate to updating control modules of a handle component based on control modules of the shaft component; however, a person of skill in the art will readily appreciate that, in other contemplated circumstances, the control modules of the shaft component and/or a different modular component may be updated instead of or in addition to the control modules of the handle component. 
     In various instances, the surgical instrument  14100  ( FIGS. 109 and 110 ) can compare the control module(s)  14152 ′ at each tier or level in the control system  14150 ′ to the control module(s)  14152  at each corresponding tier or level in the control system  14150 . If the control modules  14152  and  14152 ′ in corresponding tiers are different, a control system  14150 ,  14150 ′ can update the non-default control module(s), for example. Referring to  FIG. 112 , at step  14201 , the control system  14150  and/or the control system  14150 ′ can compare the control module(s)  14152 ′ of the first tier  14144 ′ of the first component  14110  to the control module(s)  14152  of the first tier  14144  of the second component  14120 . Where the first tiers  14144 ,  14144 ′ comprise high-level clinical algorithms  14154 ,  14154 ′, respectively, the control system  14150  and/or the control system  14150 ′ can compare the clinical algorithms  14154  and  14154 ′, for example. Furthermore, at step  14203 , if the control modules  14152 ,  14152 ′ in the first tiers  14144 ,  14144 ′ are different, the control system  14150  and/or the control system  14150 ′ can update the module(s)  14152 ′ of the first tier  14144 ′ with the default module(s)  14152  of the first tier  14144 , for example. In various instances, the control system  14150  can compare and/or update a control system and/or control modules and, in other circumstances, the control system  14150 ′ can compare and update a control system and/or control modules, for example. In various instances, one of the control systems  14150 ,  14150 ′ can be configured to compare and/or update a control system and/or control modules and, in other instances, both control systems  14150 ,  14150 ′ can be configured to compare and/or update a control system and/or control modules. 
     At step  14205 , the control system  14150  and/or the control system  14150 ′ can compare the control modules  14152 ′ of the second tier  14146 ′ of the first component  14110  to the control modules  14152  of the second tier  14146  of the second component  14120 . For example, where the second tiers  14146 ,  14146 ′ comprise mid-level framework algorithms  14156 ,  14156 ′, the control systems  14150 ,  14150 ′ can compare the framework algorithms  14156  and  14156 ′, for example. At step  14207 , if the modules  14152 ,  14152 ′ in the second tiers  14146 ,  14146 ′ are different, the control systems  14150 ,  14150 ′ can update the control modules  14152 ′ of the second tier  14146 ′ with the default control modules  14152  of the second tier  14146 . In various instances, though one or more of the control modules  14152 ′ in the second tier  14146 ′ can be the same as a corresponding module  14152  in the second tier  14146 , all control modules  14152 ′ of the second tier  14146 ′ can be updated if any corresponding second tier modules  14152 ,  14152 ′ are different. In other instances, as described in greater detail herein, only the control module(s)  14152 ′ that is/are different than the corresponding module(s)  14152  may be updated. 
     At step  14209 , the control systems  14150  and/or the control system  14150 ′ can compare the control modules  14152 ′ of the third tier  14148 ′ of the first component  14110  to the control modules  14152  of the third tier  14148  of the second component  14120 . For example, where the third tiers  14148 ,  14148 ′ comprise firmware modules  14158 ,  14158 ′, the control system  14150  and/or the control system  14150 ′ can compare the firmware modules  14158  and  14158 ′, for example. If the modules  14152 ,  14152 ′ in the third tiers  14148 ,  14148 ′ are different, the control system  14150  and/or the control system  14150 ′ can update the control modules  14152 ′ of the third tier  14148 ′ with the default control modules  14152  of the third tier  14148  at step  211 . In various instances, though one or more of the control modules  14152 ′ in the third tier  14148 ′ can be the same as a corresponding control module  14152  in the third tier  14148 , all modules  14152 ′ of the third tier  14148 ′ can be updated if any corresponding third tier modules  14152 ,  14152 ′ are different. In other instances, only the control module(s)  14152 ′ that is/are different than the corresponding control module(s)  14152  may be updated, as described in greater detail herein. Referring still to  FIG. 112 , the first tier control modules  14154 ,  14154 ′ can be updated prior to the second tier control modules  14156 ,  14156 ′, for example, and the second tier control modules  14156 ,  14156 ′ can be updated prior to the third tier control modules  14158 ,  14158 ′, for example. In other instances, as described in greater detail herein, the third tier control modules  14158 ,  14158 ′ can be updated prior to the second tier control modules  14156 ,  14156 ′, for example, and the second tier control modules  14156 ,  14156 ′ can be updated before the first tier control modules  14154 ,  14154 ′, for example. 
     As described above, the control system  14150  and/or the control system  14150 ′ may compare the control system  14150 ,  14150 ′ and/or the control modules  14152 ,  14152 ′ thereof prior to updating, replacing and/or overwriting an outdated control module  14152 ,  14152 ′ and/or control systems  14150 ,  14150 ′. A reader will appreciate that this step can reduce the instrument startup time when software updates and/or upgrades are unnecessary or unmerited. Alternatively, the comparison steps  14201 ,  14205 , and  14209  could be eliminated, and the control systems  14150 ,  14150 ′ may automatically update, replace, revise and/or overwrite the control module(s)  14152 ′ of the first modular component  14110  and/or specific, predetermined control module(s)  14152  of the first modular component  14110 , for example. 
     In various instances, the control modules  14152 ,  14152 ′ can be compared and updated on a tier-by-tier basis and, in other instances, the control systems  14150 ,  14150 ′ can be compared and updated on a system-by-system basis. In still other instances, the control modules  14152 ,  14152 ′ can be updated on a module-by-module basis. For example, referring now to  FIG. 113 , at step  14221 , a third tier module  14158 ′ of the first control system  14150 ′ can be compared to a corresponding third tier module  14158  of the second control system  14150 . In various instances, the effective date of the third tier module  14158 ′ can be compared to the effective date of the corresponding third tier module  14158 . Moreover, the control system  14150  and/or the control system  14150 ′ can determine if the effective date of the third tier module  14158 ′ postdates the effective date of the third tier module  14158 . If the third tier module  14158 ′ is newer than the third tier module  14158 , for example, the third tier module  14158 ′ can be preserved at step  14225 . Conversely, if the third tier module  14158 ′ is not newer than the third tier module  14158 , i.e., the third tier module  14158  predates the corresponding third tier module  14158  or the third tier module  14158  and the corresponding third tier module  14158 ′ have the same effective date, the third tier module  14158 ′ can be updated, replaced, revised, and/or overwritten by the corresponding third tier module  14158 , for example. Furthermore, in various instances, steps  14221  and either  14223  or  14225  can be repeated for each module  14158 ,  14158 ′ in the third tier of the control systems  14150 ,  14150 ′. Accordingly, the modules  14158 ′ in the third tier  14148 ′ may be updated on a module-by-module basis, and in various instances, only outdated modules  14158 ′ can be updated and/or overwritten, for example. 
     Referring still to  FIG. 113 , after all third tier modules  14158 ,  14158 ′ have been compared and possibly updated, the control systems  14150 ,  14150 ′ can progress to step  14227 . At step  14227 , the control system  14150  and/or the control system  14150 ′ can confirm that a third tier module  14158 ′ of the first control system  14150 ′ is connected and/or in proper communication with a second tier module  14156 ′ of the control system  14150 ′. For example, in circumstances where the third tier module  14158 ′ was updated at step  14223 , the second tier module  14156 ′ may be disconnected from the updated third tier module  14158 ′. If the third tier module  14158 ′ is disconnected from the second tier module  14156 ′, for example, the second tier module  14156 ′ can be updated, replaced, revised, and/or overwritten at step  14229 . The second tier module  14156 ′ can be replaced by the corresponding second tier module  14156  of the second control system  14150 , for example. Conversely, if the third tier module  14158 ′ is properly connected and/or in communication with the second tier module  14156 ′, the second tier module  14156 ′ can be preserved. Furthermore, in various instances, steps  14227  and either  14229  or  14231  can be repeated for each module  14158 ,  14158 ′ in the third tier of the control systems  14150 ,  14150 ′. Accordingly, the modules  14156 ′ in the second tier  14146 ′ may be updated on a module-by-module basis, and in various instances, only disconnected modules  14156 ′ can be updated or overwritten, for example. 
     After updating any outdated third tier modules  14158 ′ (steps  14221  and  14223 ) and ensuring all updated third tier modules  14158 ′, if any, are connected to the appropriate second tier module  14156 ′ on the first modular component  14110  (steps  14227 ,  14229 , and  14231 ), the control systems  14150 ,  14150 ′ can progress to step  14233 , wherein the first tier module  14154 ′ of the first control system  14150 ′ can be compared to a corresponding first tier module  14154  of the second control system  14150 . If the first tier modules  14154 ,  14154 ′ are the same, the updating and/or revising process can be complete. Conversely, if the first tier modules  14154 ,  14154 ′ are different, the first tier module  14154 ′ of the first control system  14150 ′ can be updated, replaced, revised, and/or overwritten by the first tier module  14154  of the second control system  14150 . 
     As described herein, the software and/or firmware modules of the modular components  14110 ,  14120  can be updated, revised, and/or replaced on a module-by-module, tier-by-tier, and/or system-by-system basis. In certain instances, the updating and/or revision process can be automatic when the modular components are attached and/or operably coupled. In other circumstances, an operator of the surgical instrument  14100  can initiate or trigger the updating and/or revision process described herein. 
     In various instances, a modular surgical instrument, such as the modular surgical instrument  14100  ( FIGS. 109 and 110 ), for example, can include a microcontroller in signal communication with an engagement sensor and a display. In various instances, the engagement sensor can detect the relative positioning of modular components of the surgical system. Referring again to  FIGS. 109 and 110 , where the first modular component  14110  comprises a handle and the second modular component  14120  comprises a shaft, for example, an engagement sensor can detect whether the shaft  14120  is engaged with and/or operably coupled to the handle  14110 . In various instances, the shaft  14120  can be moveable between engagement with the handle  14110  ( FIG. 109 ) and disengagement from the handle  14110  ( FIG. 110 ). 
     Referring primarily to  FIGS. 114A and 114B , an engagement sensor, such as the engagement sensor  14602 , for example, can be in signal communication with a microcontroller, such as the microcontroller  14604 , for example, of a surgical system. In various instances, the engagement sensor  14602  can detect whether the modular components  14110 ,  14120  are engaged or disengaged, for example, and can communicate the engagement or lack thereof to the microcontroller  14604 , for example. When the engagement sensor  14602  indicates that the shaft  14120  is engaged with the handle  14110 , for example, the microcontroller  14604  can permit a surgical function by the modular surgical instrument  14100  ( FIG. 109 ). If the modular components  14110 ,  14120  are operably coupled, for example, an actuation of the firing trigger  14112  ( FIG. 109 ) on the handle  14110  can affect, or at least attempt to affect, a firing motion in the shaft  14120 , for example. Conversely, if the engagement sensor  14602  indicates that the shaft  14120  is disengaged from the handle  14110 , the microcontroller  14604  can prevent a surgical function. For example, if the modular components  14110 ,  14120  are disconnected, an actuation of the firing trigger  14612  may not affect, or not attempt to affect, a firing motion in the shaft  14120 . 
     In various instances, the modular surgical instrument  14100  can include a display, such as the display  14606  ( FIG. 114(B) ), for example. The display  14606  can be integrated into one of the modular components  14110 ,  14120  of the surgical instrument  14100  and/or can be external to the modular components  14110 ,  14120  and in signal communication with the microcontroller  14604  of the surgical instrument  14100 . In various instances, the microcontroller  14604  can communicate the information detected by the engagement sensor  14602  to the display  14606 . For example, the display  14606  can depict engagement and/or non-engagement of the modular components  14110 ,  14120 . Moreover, in various instances, the display  14606  can provide instructions and/or guidance regarding how to (a) properly attach, couple, and/or engage the disengaged components  14110 ,  14120  of the surgical instrument  14100 , and/or how to (b) properly un-attach, decouple, and/or disengage the engaged components  14110 ,  14120  of the surgical instrument  14100 . Referring again to  FIG. 114A , in various instances, the engagement sensor  14604  can comprise a Hall Effect switch, and in other instances, the engagement sensor can comprise a different and/or additional sensor and/or switch, for example. 
     In certain circumstances, the engagement sensor  14604  can detect the degree of engagement between modular components of a surgical instrument. In instances where the first component comprises the handle  14110 , for example, and the second component comprises the shaft  14120 , for example, the handle  14110  and the shaft  14120  can move between a disengaged position, a partially-engaged position, and an engaged position. The partially-engaged position can be intermediate the disengaged position and the engaged position, for example, and there may be multiple partially-engaged positions intermediate the engaged position and the disengaged position, for example. In various instances, the engagement sensor  14604  can include a plurality of sensors, which can detect the partially-engaged position(s) of the components  14110 ,  14120 . For example, the engagement sensor  14606  can comprise a plurality of sensors and/or electrical contacts, for example, which can be staggered along an attachment portion of at least one of the modular components  14110 ,  14120 , for example. In certain instances, the engagement sensor(s)  14604  can comprise a Hall Effect sensor, for example. 
     In certain instances, referring primarily to  FIGS. 115A and 115B , the surgical system  14100  can include multiple sensors in signal communication with a microcontroller, such as the microcontroller  14614 , for example. The multiple sensors can include a first sensor  14612  ( FIG. 115A ), which can detect the presence of the first component  14120 , and can communicate the presence of the first component  14120  to the microcontroller  14614 , for example. In various instances, the first sensor  14612  may not detect and/or communicate the degree of engagement between the first component  14110  and the second component  14120 , for example. In various instances, a second sensor  14613  ( FIG. 115A ) can also be in signal communication with the microcontroller  14614 . The second sensor  14613  can detect the degree of engagement between the modular components  14110 ,  14120 , for example. 
     Similar to the control system depicted in  FIGS. 114A and 114B , the microcontroller  14614  can issue commands based on the feedback received from the sensors  14612  and  14613 , and/or can be in signal communication with a display to display the feedback and/or otherwise communicate with an operator of the surgical system. For example, the microcontroller  14614  can prevent a surgical function until the modular components  14110 ,  14120  are in the engaged position, and can prevent a surgical function when the modular components  14110 ,  14120  are partially-engaged, for example. Furthermore, the microcontroller  14614  can communicate the information detected by the engagement sensor to a display. For example, the display can depict engagement, partial-engagement and/or non-engagement of the modular components  14110 ,  14120 . Moreover, in various instances, the display can provide instructions and/or guidance regarding how to properly attach, couple, and/or engage disengaged and/or partially-engaged components  14110 ,  14120  of the surgical instrument, for example. 
     In various instances, a surgical instrument can include a microprocessor such as the microprocessor  14604  ( FIGS. 114A and 114B ) or  14614  ( FIGS. 115A and 115B ), for example, which can be in signal communication with a memory chip or memory unit. The microprocessor can communicate data and/or feedback detected and/or calculated by the various sensors, programs, and/or circuits of the surgical instrument to the memory chip, for example. In various instances, recorded data can relate to the time and/or duration of the surgical procedure, as well as the time and/or duration of various functions and/or portions of the surgical procedure, for example. Additionally or alternatively, recorded data can relate to conditions at the treatment site and/or conditions within the surgical instrument, for example. In certain instances, recordation of data can be automatic and, in other instances, the microprocessor may not record data unless and/or until instructed to record data. For example, it may be preferable to record data during a surgical procedure, maintain or store the recorded data in the memory chip, and/or transfer the recorded data to a secure site. In other circumstances, it may be preferable to record data during a surgical procedure and delete the recorded data thereafter, for example. 
     A surgical instrument and/or microcontroller thereof can comprise a data storage protocol. The data storage protocol can provide rules for recording, processing, storing, transferring, and/or deleting data, for example. In various instances, the data storage protocol can be preprogrammed and/or updated during the lifecycle of the surgical instrument. In various instances, the data storage protocol can mandate deletion of the recorded data after completion of a surgical function and/or surgical operation and, in other instances, the data storage protocol can mandate deletion of the recorded data after the elapse of a predefined period of time. For example, recorded data can be deleted, in accordance with the data storage protocol, one minute, one hour, one day, one week, one month or one year after the surgical function. The predefined period of time can be any suitable and appropriate period permitted by the circumstances. 
     In certain circumstances, the data storage protocol can mandate deletion of the recorded data after a predefined number of surgical functions, such as firing strokes, for example. In still other instances, the data storage protocol can mandate deletion of the recorded data when the surgical instrument is powered off. For example, referring to  FIG. 117 , if the surgical instrument is powered off, the microcontroller can proceed to step  14709 , wherein the microcontroller can determine if an error or major issue, such as an instrument, component or subsystem failure, for example, occurred during the surgical procedure. In various instances, if an error is detected, the microcontroller can proceed to step  14713 , wherein the data can be stored in the memory chip, for example. Moreover, in certain instances, if an error is not detected, the microcontroller can proceed to step  14711 , wherein the data can be deleted, for example. In other instances, the data storage protocol may not comprise the step  14709 , and the data storage protocol can continue without checking for a major error or failure, for example. 
     In still other instances, the data storage protocol can mandate deletion of the recorded data after a predefined period of inactivity or stillness of the surgical instrument. For example, if the surgical instrument is set down and/or put into storage, the data storage protocol can mandate deletion of the recorded data after the surgical instrument has been still or idle for a predefined period of time. The requisite period of stillness can be one minute, one hour, one day, one week, one month, or one year, for example. The predefined period of stillness can be any suitable and appropriate period permitted by the circumstances. In various instances, the surgical instrument can include an accelerometer, for example, which can detect movement and stillness of the surgical instrument. Referring again to  FIG. 117 , when the surgical instrument has not been powered off at step  14701 , the accelerometer can be set to detect movement of the surgical instrument. If movement is detected at step  14703 , prior to lapsing of the predefined idle period at step  14707 , the predefined idle time count can be restarted at step  14705 . Conversely, if movement is not detected by the accelerometer prior to lapsing of the predefined idle period at step  14707 , the microprocessor can proceed to step  14709 , for example. In other circumstances, the microprocessor can proceed directly to step  14711  or  14713 , depending on the data storage protocol, without checking for an instrument error or failure, for example. 
     As described herein, the data storage protocol can include one of more default rules for deleting recorded data. In certain instances, however, it may be desirable to override the default rule or procedure. For example, for research and/or development purposes, it may be desirable to store recorded data for a longer period of time. Additionally or alternatively, it may be desirable to store recorded data for teaching and/or investigative purposes. Moreover, in various instances, the data storage protocol may not include an error-checking step and, in such instances, it may be desirable to override the data storage protocol and ensure storage of data when the operator detects or suspects an error and/or anomaly during a surgical procedure, for example. The recovered data can facilitate review of the procedure and/or a determination of the cause of the error, for example. In various instances, a key or input may be required to overcome or override the standard data storage protocol. In various instances, the key can be entered into the surgical instrument and/or a remote storage device, and can be entered by an operator and/or user of the surgical instrument, for example. 
     In various instances, a surgical system may prompt the user or instrument operator to select either data deletion or data storage for each surgical procedure or function. For example, the data storage protocol may mandate solicitation of instructions from the user, and may command subsequent action in accordance with the user&#39;s instructions. The surgical system may solicit instructions from the user upon the occurrence of a particular trigger event, such as powering down of the instrument, the elapse of a predefined period of time, or the completion of a particular surgical function, for example. 
     In certain instances, the surgical system can request input from a user when the surgical instrument is powered down, for example. Referring to  FIG. 116 , when a user initiates powering off of a surgical instrument at step  14801 , for example, the surgical system can request data storage instructions from the user. For example, at step  14803 , a display of the surgical system can ask, “KEEP DATA Y/N?” In various instances, the microcontroller of the surgical system can read the user input at step  14805 . If the user requests storage of the data, the microcontroller can proceed to step  14809 , wherein the data is stored in a memory unit or memory chip of the surgical system. If the user requests deletion of the data, the microcontroller can proceed to step  14811 , wherein the data is erased. In various instances, the user may not enter input. In such instances, the data storage protocol can mandate a particular process at step  14813 . For example, the data storage protocol may mandate “Process I”, “Process II”, or an alternative process, for example. In certain instances, “Process I” can command the deletion of data at step  14813 ( a ), and “Process II” can command the storage of data at step  14813 ( b ), for example. In various circumstances, the user can provide instructions to the surgical instrument before instruction have been solicited, for example. Additionally or alternatively, a display associated with the surgical system can request instruction from the user prior to initiating the surgical function and/or at different time(s) during instrument use, for example. 
     If data is stored in the memory of the surgical instrument, the data can be securely stored. For example, a code or key may be required to access the stored data. In certain instances, the access key can comprise an identification code. For example, the identification code can be specific to the operator, user, or owner of the surgical instrument. In such instances, only an authorized person can obtain a licensed identification code, and thus, only authorized personnel can access the stored data. Additionally or alternatively, the access key can be specific to the instrument and/or can be a manufacturer&#39;s code, for example. In certain instances, the access key can comprise a secure server, and data can be transferred and/or accessed by an approved Bluetooth and/or radio frequency (RF) transmission, for example. In still other circumstances, the access key can comprise a physical key, such as memory key and/or a data exchange port connector, which can be physically coupled to a data exchange port of the surgical instrument. In such instances, the access key can be preprogrammed to obtain access to the secure data, and to securely store and/or transfer the data, for example. In various circumstances, an access key can correspond to a specific surgical instrument, for example. 
     In various instances, data extraction from the memory device of a surgical instrument can be restricted by various security measures. In certain instances, the memory device of the surgical instrument can comprise a secure data connection or data exchange port. For example, the data exchange port can have a proprietary geometry or shape, and only authorized personnel can obtain a corresponding port key designed and structured to fit the proprietary geometry or shape, for example. In various instances, the data exchange port can comprise a mechanical lock, which can comprise a plug, a plurality of pins, and/or a plurality of springs, for example. In various instances, a physical key or extraction device can unlock the mechanical lock of the data exchange port. For example, the physical key can contact the plurality of pins, deform the plurality of springs, and/or bias the plug from a locked orientation to an unlocked orientation to unlock the data exchange port, for example. 
     In various instances, the data exchange port can comprise at least one connection pin, which can be biased and/or held in a first position. When a physical key is inserted into and/or engages the data exchange port, the physical key can bias the connection pin from the first position to a second position, for example. In various instances, the first position can comprise a retracted position, for example, and the second position can comprise an extended position, for example. Moreover, when the connection pin is moved to the second position, the connection pin can operably interface with a data connection port in the physical key, for example. Accordingly, the data exchange port of the memory device can move into signal communication with the data exchange port of the physical key via the connection pin, for example, such that data can be exchanged and/or transferred therebetween. In various instances, the physical key can comprise a modular component, for example, which can be configured to removably attach to the modular surgical instrument. In certain instances, the physical key can replace or mimic a modular component  14110 ,  14120  of a surgical instrument  14100  ( FIGS. 109 and 110 ). For example, the physical key can attach to an attachment portion of the handle  14110  in lieu of a shaft attachment  14120 , for example, for the transfer of data from a memory device in the handle  14120 . 
     Additionally or alternatively, the key or extraction device can comprise a security token. In various instances, the data exchange port can be encrypted, for example, and/or the key can provide information or codes to the data exchange port to verify that the key is authorized and/or approved to extract data from the data exchange port. In certain circumstances, the key can comprise a specialized data reader, for example, and data can be transferred via an optical data transmission arrangement, for example. 
     Referring now to  FIGS. 118A-118C , before data access is granted to a proposed data reader, the data reader may need to be verified and/or confirmed by the surgical instrument. For example, the proposed data reader can request and read a checksum value of the surgical instrument at step  14821 . As depicted in the surgical instrument flowchart depicted in  FIG. 118C , the surgical instrument can first receive the proposed data reader request at step  14841 , and can then send the checksum value to the proposed data reader at step  14843 . Referring again to  FIG. 118A , at step  14823 , the proposed data reader can calculate or determine an appropriate return code based on the checksum value provided by the surgical instrument. The proposed data reader can have access to a code table, for example, and, if the proposed data reader is appropriately attempting to access the data, the appropriate return code can be available in the code table. In such instances, the proposed data reader can pull or calculate the return code at step  14823  and can send the return code to the surgical instrument at step  14825 . Referring again to  FIG. 118C , upon receiving the return code from the proposed data reader at step  14845 , the surgical instrument can verify that the return code is correct at step  14847 . If the code is incorrect, the microprocessor of the surgical instrument can proceed to step  14849 , for example, and the surgical instrument can be shut down, or access to the stored data can be otherwise denied. However, if the code is correct, the microprocessor can proceed to step  14851 , for example, and the surgical instrument can provide data access to the proposed data reader. For example, the data can be securely transferred to the data reader at step  14851 . Thereafter, at step  14827  ( FIG. 118A ), the proposed data reader can read the data from the surgical instrument, for example. In various instances, the transferred data can be encrypted, for example, and the data reader may need to decrypt the unintelligible data prior to reading it, for example. 
     Referring primarily to  FIG. 118B , an alternate data extraction security method can be similar to the method depicted in  FIG. 118A , for example, and can also require the consideration of a reader-specific code. Although the reader can read the checksum of the device at step  14831  and the return code can be based on the checksum, in various circumstances, the proposed data reader can have a reader-specific code, and the appropriate return code from the code table can be based on the reader-specific code. For example, the proposed data reader can consider the reader-specific code at step  14832 , and can determine the appropriate return code at step  14833  based on the reader-specific code and the code table, for example. The proposed data reader can provide the reader-specific code and the return code to the surgical instrument at step  14835 , for example. In such instances, referring again to  FIG. 118C , the microcontroller of the surgical instrument can verify the return code and reader-specific code, at step  14845 . Moreover, if these codes are correct, the surgical instrument can provide access to the proposed data reader. Thereafter, at step  14827 , the proposed data reader can read the data from the surgical instrument, for example. If one or both of the codes are incorrect, the surgical instrument can prevent the reader from reading the data. For example, the surgical instrument can shut down or otherwise restrict the transfer of data to the reader. 
     Referring now to  FIG. 119 , in various instances, a surgical system can comprise a surgical instrument  21600 , which can be formed from a plurality of modular components. As described in greater detail herein, a handle component can be compatible with a plurality of different shaft components, for example, and the handle component and/or the shaft components can be reusable, for example. Moreover, a microcontroller of the surgical instrument  21600  can include a locking circuit, for example. In various instances, the locking circuit can prevent actuation of the surgical instrument until the locking circuit has been unlocked, for example. In various circumstances, the operator can enter a temporary access code into the surgical system to unlock the locking circuit of the microcontroller, for example. 
     In various circumstances, the operator can purchase or otherwise obtain the temporary access code for entering into the surgical system. For example, the instrument manufacturer or distributor can offer access codes for sale, and such access codes can be required in order to unlock, and thus use, the surgical instrument  21660 . In various instances, the access code can unlock the locking circuit for a predefined period of time. The instrument manufacturer or distributor can offer different durations of use for purchase, and the user can select and purchase or acquire, a desired or preferable duration of use. For example, the user may acquire ten minutes of use, one hour of use, or one day of use. In other instances, additional and/or different suitable periods of use can be offered for sale or authorization. In various instances, after the acquired period of use expires, the locking circuit can be relocked. In other instances, an access code can unlock the locking circuit for a predefined number of surgical functions. For example, a user may purchase or otherwise obtain a single instrument firing or multiple firings, for example. Moreover, after the user has fired the instrument the purchased or authorized number of times, the locking circuit can be relocked. In still other instances, an access code can permanently unlock the locking circuit, for example. 
     In various instances, the operator can enter the temporary access code directly into the surgical system via a keypad or other suitable input arrangement. In other instances, the locking circuit can be unlocked by coupling a nonvolatile memory unit to the surgical instrument  21600 , wherein the nonvolatile memory unit comprises a preprogrammed access code. In various instances, the nonvolatile memory unit can be loaded into a battery  21650  of the surgical instrument  21660 , for example. Moreover, the nonvolatile memory unit can be reloaded and/or replaced. For example, the user can purchase replacement nonvolatile memory units. Additionally or alternatively, new codes can be purchased and uploaded to the nonvolatile memory unit, for example, after the previously-obtained access codes expire or lapse. In various instances, new codes can be loaded onto the nonvolatile memory unit when the battery  1650  is coupled to a power source and/or external computer  21670 , for example. 
     In other instances, the temporary access code can be entered into an external or remote access code input, such as a display screen, computer, and/or heads up display. For example, a temporary access code can be purchased via a computer  21660 , and can be transmitted to a radio frequency (RF) device  21680  coupled to the computer  21660 . In various instances, the surgical instrument  21600  can comprise a receiver or antenna, which can be in signal communication with the radio frequency device  21680 , for example. In such instances, the radio frequency device  21680  can transmit the acquired temporary access code(s) to the surgical instrument  21600  receiver, for example. Accordingly, the locking circuit can be unlocked, and the operator can use the surgical instrument  21600  for the purchased time period and/or number of surgical functions, for example. 
     In various instances, a modular surgical instrument may be compatible with an external display for depicting data and/or feedback from the surgical instrument. For example, the surgical instrument can comprise an instrument display for displaying feedback from the surgical procedure. In various instances, the instrument display can be positioned on the handle of the instrument, for example. In certain instances, the instrument display can depict a video feed viewed from an endoscope, for example. Additionally or alternatively, the display can detect sensed, measured, approximated, and/or calculated characteristics of the surgical instrument, surgical operation, and/or surgical site, for example. In various instances, it may be desirable to transmit the feedback to an external display. The external display can provide an enlarged view of the duplicated and/or reproduced feedback, for example, which can allow multiple operators and/or assistants to simultaneously view the feedback. In various instances, it may be desirable to select the surgical instrument for connection to the external display, for example, and, in other instances, the selection of a surgical instrument may be automatic. 
     Referring to  FIG. 120 , an external display  21700  can depict an end effector  21720  of a surgical instrument and/or the surgical site, for example. The external display  21700  can also depict feedback and/or data sensed and/or measured by the surgical instrument, for example. In various instances, the external display  21700  can duplicate feedback provided on the display of the surgical instrument. In certain circumstances, the surgical instrument can automatically connect with the external display  21700  and/or a wireless receiver in signal communication with the external, or operating room, display  21700 , for example. In such instances, an operator can be notified if multiple surgical instruments are attempting to connect to the external display  21700 . As described herein, the operator can select the desired surgical instrument(s) from a menu on the external display  21700 , for example. In still other instances, the operator can select the desired surgical instrument by providing an input to the surgical instrument. For example, the operator can issue a command, control sequence, or input a code to select the surgical instrument. In various instances, the operator may complete a specific control sequence with the surgical instrument to select that surgical instrument. For example, the operator may power on the surgical instrument and, within a predefined period of time, hold down the reverse button for a predefined period of time, for example, to select the surgical instrument. When an instrument is selected, the feedback on the selected instrument display can be rebroadcast or duplicated on the external display  21700 , for example. 
     In certain instances, the surgical system can include a proximity sensor. For example, the external display and/or wireless receiver can comprise a proximity sensor, which can detect when a surgical instrument is brought within a predefined range thereof. Referring primarily to  FIGS. 121 and 122 , when the display  21700  and/or wireless receiver detect a surgical instrument, the display can notify the user. In certain circumstances, the display and/or wireless receiver may detect multiple surgical instruments. Referring to  FIG. 121 , the display  21700  can include a non-obtrusive notification  21704 , for example, which can communicate to the user that a surgical instrument, or multiple surgical instruments, have been detected in the proximity of the display  21700 . Accordingly, using the controls for the display  21700 , such as a computer, for example, the user can click the notification  21704  to open the menu  21706  of instrument selections ( FIG. 122 ). The menu  21706  can depict the available surgical instruments, for example, and the user can select the preferred surgical instrument for broadcasting on the display  21700 . For example, the menu  21706  can depict the serial numbers and/or names of the available surgical instruments. 
     In certain instances, the selected surgical instrument can provide feedback to the operator to confirm its selection. For example, the selected surgical instrument can provide auditory or haptic feedback, for example. Additionally, the selected surgical instrument can broadcast at least a portion of its feedback to the external display  21700 . In certain instances, the operator can select multiple surgical instruments and the display  21700  can be shared by the selected surgical instruments. Additionally or alternatively, the operating room can include multiple displays and at least one surgical instrument can be selected for each display, for example. Various surgical system features and/or components are further described in U.S. patent application Ser. No. 13/974,166, filed Aug. 23, 2013, and titled FIRING MEMBER RETRACTION DEVICES FOR POWERED SURGICAL INSTRUMENTS, now U.S. Pat. No. 9,700,310, which is hereby incorporated by reference in its entirety. 
     Referring again to the shaft assembly  200  shown in  FIGS. 8-12 , the shaft assembly  200  comprises a slip ring assembly  600  which is configured to conduct electrical power to and/or from the end effector  300  and/or communicate signals to and/or from the end effector  300 , for example. The slip ring assembly  600  comprises a proximal connector flange  604  mounted to a chassis flange  242  extending from the chassis  240  and, in addition, a distal connector flange  601  positioned within a slot defined in the shaft housings  202 ,  203 . The proximal connector flange  604  comprises a plurality of concentric, or at least substantially concentric, conductors  602  defined in the first face thereof. A connector  607  is mounted on the proximal side of the distal connector flange  601  and may have a plurality of contacts, wherein each contact corresponds to and is in electrical contact with one of the conductors  602 . Such an arrangement permits relative rotation between the proximal connector flange  604  and the distal connector flange  601  while maintaining electrical contact there between. The proximal connector flange  604  can include an electrical connector  606  which places the conductors  602  in signal communication with a shaft circuit board  610  mounted to the shaft chassis  240 , for example. In at least one instance, a wiring harness comprising a plurality of conductors can extend between the electrical connector  606  and the shaft circuit board  610 . The electrical connector  606  extends proximally through a connector opening  243  defined in the chassis mounting flange  242 , although any suitable arrangement can be used. 
     Alternative embodiments of the shaft assembly  200  are depicted in  FIGS. 123-136 . These embodiments include shaft assembly  25200  in  FIGS. 123 and 124 , shaft assembly  26200  in  FIGS. 126-129 , shaft assembly  27200  in  FIGS. 131-133 , and shaft assembly  28200  in  FIGS. 134-136 . The shaft assemblies  25200 ,  26200 ,  27200 , and  28200  are similar to the shaft assembly  200  in many respects, most of which will not be discussed herein for the sake of brevity. Moreover, certain components have been removed from  FIGS. 123-136  to more clearly illustrate the differences between the shaft assemblies  25200 ,  26200 ,  27200 , and  28200  and the shaft assembly  200 . 
     The shaft assembly  25200  comprises an articulation drive system, an end effector closure system, and a stapling firing system. Similar to the above, the articulation drive system is selectively engageable with the staple firing system. When the articulation drive system is operably engaged with the staple firing system, the staple firing system can be used to drive the articulation drive system and articulate the end effector. When the articulation is not operably engaged with the staple firing system, the articulation drive system is not drivable by the staple firing system, and the staple firing system can be used to perform a staple firing stroke. 
     As mentioned above, the shaft assembly  25200  depicted in  FIGS. 123 and 124  is similar in many respects to the shaft assembly  200  depicted in  FIGS. 8-12 . Although not shown, the shaft assembly  25200  comprises the nozzle housing  203  depicted in  FIG. 10 . The shaft assembly  25200  further comprises a rotatable switch drum  25500 , a torsion spring  25420 , and a chassis mounting flange  25242 . The switch drum  25500  is rotatable between a first position and a second position relative to the chassis mounting flange  25242 . As discussed in greater detail below, the torsion spring  25420  is mounted to the switch drum  25500  and the nozzle housing  203 . The torsion spring  25420  is configured to bias the switch drum  25500  into its first position. When the switch drum  25500  is in its first position, the articulation drive system is operably engaged with the firing drive system. Thus, when the switch drum  25500  is in its first position, the firing drive system may drive the articulation drive system to articulate the end effector of the shaft assembly  25200 . When the switch drum  25500  is in its second position, the articulation drive system is operably disengaged from the firing drive system. Thus, when the switch drum  25500  is in its second position, the firing drive system will not drive the articulation drive system. 
     The torsion spring  25420  comprises a first end  25421  and a second end  25423 . The switch drum  25500  comprises a hollow shaft segment  25502  that has a shaft boss  25504  formed thereon. The first end  25241  of the torsion spring  25420  is engaged with the nozzle housing  203  and the second end  25423  of the torsion spring  25420  is engaged with the boss  25504  on the switch drum  25500 . As the switch drum  25500  is rotated from a first position to a second position to decouple the articulation drive system from the staple firing system, the first end  25241  of the torsion spring  25420  remains stationary with respect to the nozzle housing  203  while the second end  25423  of the torsion spring  25420  travels with the switch drum  25550 . The displacement of the second end  25423  relative to the first end  25421  of the torsion spring  25420  causes the torsion spring  25420  to be stretched, resulting in a decrease in the inductance of the torsion spring  25420 . Rotation of the switch drum  25500  back to the first position results in the elastic contraction of the torsion spring  25420  and an increase in the inductance of the torsion spring  25420 , as discussed below. 
     A first wire  25422  and a second wire  25424  are electrically connected to the first end  25241  and the second end  25423  of the torsion spring  25420 , respectively. As discussed in greater detail below, the first wire  25422 , the second wire  25424 , and the torsion spring  25420  form an electrical circuit which is used to monitor an operating state or mode of the shaft assembly  25200 . The electrical circuit is in communication with a circuit board  25610  positioned in the shaft assembly  25200 . In various instances, the shaft circuit board  25610  comprises an Inductance-to-Digital Converter (LDC)  25612  which is part of the electrical circuit and configured to monitor changes in the inductance of the torsion spring  25420 . 
     An exemplary operating state that can be monitored through the electrical circuit is an articulation state. As discussed above, the articulation drive system is operably engaged with the firing drive system such that the end effector can be articulated when the switch drum  25500  is in its first position. Correspondingly, the articulation drive system is operably disengaged from the firing drive system when the switch drum  25500  is in its second position.  FIG. 123  represents the shaft assembly  25200  when the switch drum  25500  is in its first position. In the first position of the switch drum  25500 , the torsion spring  25420  is either unstretched or only partially stretched. The depiction of the shaft assembly  25200  in  FIG. 124  shows the switch drum  25500  in its second position, wherein the torsion spring  25420  is noticeably stretched. A stretched torsion spring  25420  has a different inductance than an unstretched torsion spring  25420 . Furthermore, a stretched torsion spring  25420  has a different inductance than a less-stretched torsion spring  25420 . The LDC  25612  detects changes in inductance within the torsion spring  25420  when and, thus, can determine whether the articulation drive system is engaged with or disengaged from the firing drive system. In various instances, the LDC  25612  can perform the calculations where, in other embodiments, a separate microprocessor in signal communication with the LDC  25612  can perform the calculations. 
       FIG. 125  depicts a graph  25900  representing the relationship between the angular position of the switch drum  25500  and the inductance of the torsion spring  25420 . When the articulation drive system is engaged with the firing drive system, the inductance of the torsion spring  25420  is high while the angular position of the switch drum  25500  is low. As the switch drum  25500  is rotated in direction R ( FIG. 124 ), the torsion spring  25420  is stretched, and the inductance of the torsion spring  25420  decreases. The lower spring inductance indicates to the LDC  25612  that the articulation drive system is disengaged from the firing drive system. Such an arrangement can verify that the switch over between the articulation state and the firing state has occurred without relying on a purely mechanical system. 
     While the above description describes monitoring inductance through rotation of the torsion spring, it is also envisioned that the articulation state of the shaft assembly could be determined or verified by measuring the linear compression, stretch of compression, and/or tension of the torsion spring, for example. Moreover, it is also envisioned that the above-described induction monitoring system can be adapted to other forms of detection throughout the shaft and handle of the surgical instrument such as, for example, monitoring the state of the closure and/or staple firing drive systems. 
       FIGS. 126-129  depict a shaft assembly  26200  that is similar in many respects to the shaft assembly  200  depicted in  FIGS. 8-12 . The shaft assembly  26200  comprises an articulation drive system, an end effector closure system, and a stapling firing system. Similar to the above, the articulation drive system is selectively engageable with the staple firing system. When the articulation drive system is operably engaged with the staple firing system, the staple firing system can be used to drive the articulation drive system and articulate the end effector. When the articulation is not operably engaged with the staple firing system, the articulation drive system is not drivable by the staple firing system, and the staple firing system can be used to perform a staple firing stroke. 
     The shaft assembly  26200  comprises a nozzle housing  26201  which is similar to the nozzle housing  203  depicted in  FIG. 10 . The shaft assembly  26200  further comprises a rotatable switch drum  26500 , a torsion spring  26420 , and a chassis mounting flange  26242 . The switch drum  26500  is rotatable between a first position and a second position relative to the chassis mounting flange  26242 . As discussed in greater detail below, the torsion spring  26420  is mounted to the switch drum  26500  and the nozzle housing  26201 . The torsion spring  26420  is configured to bias the switch drum  26500  into its first position. When the switch drum  26500  is in its first position, the articulation drive system is operably engaged with the firing drive system. Thus, when the switch drum  26500  is in its first position, the firing drive system can drive the articulation drive system to articulate the end effector of the shaft assembly  26200 . When the switch drum  26500  is in its second position, the articulation drive system is operably disengaged from the firing drive system. Thus, when the switch drum  26500  is in its second position, the firing drive system will not drive the articulation drive system. 
     The torsion spring  26420  comprises a first end  26421  and a second end  26423 . The switch drum comprises a hollow shaft segment  26502  that has a shaft boss  26504  formed thereon. The first end  26421  of the torsion spring  26420  is engaged with the nozzle housing  26201  and the second end  26423  of the torsion spring  26420  is engaged with the boss  26504  on the switch drum  26500 . As the switch drum  26500  is rotated from a first position to a second position to decouple the articulation drive system from the staple firing system, the first end  26421  of the torsion spring  26420  remains stationary with respect to the nozzle housing  203  ( FIG. 10 ) while the second end  26423  of the torsion spring  26420  travels with the switch drum  26550 . The displacement of the second end  26423  relative to the first end  26421  of the torsion spring  26420  causes the torsion spring  26420  to be elastically stretched. 
     The switch drum  26500  further comprises a conductive leaf spring  26700  attached to an outer surface of the switch drum  26500 . As discussed in greater detail below, the conductive leaf spring  26700  forms a part of an electrical circuit which is used to monitor an operating state or mode of the shaft assembly  26200 . Referring primarily to  FIG. 129 , the chassis mounting flange  26242  comprises a first annular step  26244  and a second annular step  26246 . The first annular step  26244  is positioned distal to the second annular step  26246 , and the first annular step  26244  has a smaller diameter than the diameter of the second annular step  26246 ; however, any suitable arrangement could be used. The first annular step  26244  comprises a first conductive trace  26245  wrapped around, or defined on, an outer circumference of the first annular step  26244 . The second annular step  26246  comprises a second conductive trace  26247  wrapped around, or defined on, an outer circumference of the second annular step  26246 . The first and second conductive traces  26245 ,  26247  are electrically connected to a shaft circuit board  26610  by suitable conductors. As discussed in greater detail below, the first conductive trace  26245  and the second conductive trace  26247  form part of the electrical circuit along with the conductive leaf spring  26700 . 
     As depicted in  FIGS. 127 and 128 , the nozzle  26201  comprises a plurality of inwardly-extending projections such as a first inward projection  26210  and a second inward projection  26220 . A first electrical contact  26215  is defined on the inward-most surface of the first inward projection  26210  which is aligned with the first annular step  26244  of the chassis mounting flange  26242 . A second electrical contact  26225  is defined on the inward-most surface of the second inward projection  26220  which is aligned with the second annular step  26246  of the chassis mounting flange  26244 . When the switch drum  26500  is in its first position, as shown in the depiction of the shaft assembly  26200  in  FIG. 127 , the conductive leaf spring  26700  of the switch drum  26500  is out of alignment with one or both of the first and second electrical contacts  26215  and  26225  on the first and second nozzle projections  26210  and  26220 . Thus, the circuit is open when the switch drum is in its first position, as the conductive leaf spring  26700  does not have electrical connectivity with both of the first and second electrical contacts  26215  and  26225 . When the switch drum  26500  is in its second position, the conductive leaf spring  26700  is in electrical contact with the first and second electrical contacts  26215  and  26225  and the electrical circuit is closed. In such instances, the first and second electrical contacts  26215  and  26225  can permit a signal current, for example, to pass through the circuit including the first and second conductive traces  26245  and  26247  and the shaft circuit board  26610 . A microprocessor on the shaft circuit board  26610  is configured to monitor an operating state or mode of the shaft assembly  26200  based on whether the electrical circuit is open or closed. 
     An exemplary operating state that can be monitored through the electrical circuit is an articulation state. As discussed above, when the switch drum  26500  is in its first position, the articulation drive system is operably engaged with the firing drive system, and when the switch drum  26500  is in its second position, the articulation drive system is operably disengaged from the firing drive system.  FIG. 127  represents the shaft assembly  26200  when the switch drum  26500  is in its first position. In the first position of the switch drum  26500 , the conductive leaf spring  26700  is out of alignment with one or both of the first and second electrical contacts  26215  and  26225  on the first and second inward projections  26210  and  26220  of the nozzle  26201 . In this state, the electrical circuit is open. The depiction of the shaft assembly  25200  in  FIG. 128  shows the switch drum  25500  in its second position, wherein the conductive leaf spring  26700  is in alignment and contact with the first and second electrical contacts  26215  and  26225 . In this state, the electrical circuit is closed. As described above, the electrical signal can now pass between the conductive leaf spring  26700 , the first and second electrical contacts  26215  and  26225 , and the first and second conductive traces  26245  and  26247 . A microcontroller on the shaft circuit board  26610  is configured to determine whether the articulation drive system is engaged with or disengaged from the firing drive system based on whether the electrical circuit is open or closed. 
       FIG. 130  depicts a chart  26900  detailing the relationship between the state of the above-discussed electrical circuit and whether the articulation drive system is engaged with or disengaged from the firing drive system. When the articulation drive system is engaged with the firing drive system, the electrical circuit is open because the conductive leaf spring  26700  is out of alignment with one or both of the first and second electrical contacts  26215  and  26225  on the first and second inward projections  26210  and  26220  of the nozzle  26201 . When the articulation drive system is disengaged from the firing drive system, the electrical circuit is closed because the conductive leaf spring  26700  is in alignment and in contact with the first and second electrical contacts  26215  and  26225  on the first and second inward projections  26210  and  26220  of the nozzle  26201 . 
     While the system described above monitors the state of the articulation drive system, it is also envisioned that the above-described system can be adapted to other forms of detection throughout the shaft and handle of the surgical instrument such as, for example, monitoring the state of the closure and/or staple firing drive systems. 
     The shaft assembly  27200  depicted in  FIGS. 131-133  is similar in many respects to the shaft assembly  200  depicted in  FIGS. 8-12 . The shaft assembly  27200  comprises an articulation drive system, an end effector closure system, and a stapling firing system. Similar to the above, the articulation drive system is selectively engageable with the staple firing system. When the articulation drive system is operably engaged with the staple firing system, the staple firing system can be used to drive the articulation drive system and articulate the end effector. When the articulation is not operably engaged with the staple firing system, the articulation drive system is not drivable by the staple firing system, and the staple firing system can be used to perform a staple firing stroke. 
     Although not shown, the shaft assembly  27200  comprises the nozzle housing depicted in  FIG. 10 . The shaft assembly  27200  further comprises a rotatable switch drum  27500  and a chassis mounting flange  27242 . The switch drum  27500  is rotatable between a first position and a second position relative to the chassis mounting flange  27242 . When the switch drum  27500  is in its first position, the articulation drive system is operably engaged with the firing drive system. Thus, when the switch drum  27500  is in its first position, the firing drive system may drive the articulation drive system to articulate the end effector of the shaft assembly  27200 . When the switch drum  27500  is in its second position, the articulation drive system is operably disengaged from the firing drive system. Thus, when the switch drum  27500  is in its second position, the firing drive system will not drive the articulation drive system. 
     The shaft assembly  27200  further comprises a sensing fork  27700  configured to be driven at a vibrational frequency. Referring primarily to  FIGS. 132 and 133 , the switch drum  27500  comprises a plurality of inwardly-facing projections  27502 . When the switch drum  27500  is in its first position, as illustrated in  FIG. 132 , the inwardly-facing projections  27502  are not in contact with the tines of the sensing fork  27700 . In other words, a space separates the inwardly-facing projections  27502  and the sensing fork  27700 . In such instances, the switch drum  27500  does not vibrationally dampen the sensing fork  27700 . When the switch drum  27500  is rotated in a direction R to the switch drum&#39;s  27500  second position, as illustrated in  FIG. 133 , the inwardly-facing projections  27502  come into contact with the tines of the sensing fork  27700 . In this second position, the contact between the inwardly-facing projections  27502  and the sensing fork  27700  vibrationally dampens the sensing fork  27700 . 
     Referring primarily to  FIG. 131 , the shaft assembly  27200  further comprises a shaft circuit board  27610  comprising an output actuator that is configured to emit vibrations. In various instances, the output actuator comprises a transducer that converts an electrical signal to mechanical acoustic waves and transmits the mechanical acoustic waves to the sensing fork  27700 . Such acoustic waves cause the sensing fork  27700  to vibrate, and owing to the mechanical characteristics of the sensing fork  27700 , the emitted signal can change within the sensing fork  27700 . A distal end of the shaft circuit board  27610  comprises an input transducer  27602  configured to detect the vibrational frequency within the sensing fork  27700  and monitor any changes within this frequency. As the input transducer  27602  detects the vibrational frequency of the sensing fork  27700 , the input transducer  27602  converts the detected frequency back to an electrical signal for communication with the shaft circuit board  27610  which is configured to compare the return signal to the emitted signal. In various instances, a slightly dampened sensing fork  27700  may result in a small change between the emitted signal and the return signal, if any at all, while a highly dampened sensing fork  27700  may result in a large change between the emitted signal and the return signal. A microprocessor on the shaft circuit board  27610  is configured to monitor the change in frequency and assess the operating state or mode of the shaft assembly  27200  based on the detected frequency of the sensing fork  27700 . 
     An exemplary operating state that can be monitored through the electrical circuit is an articulation state. As discussed above, when the switch drum  27500  is in its first position, the articulation drive system is operably engaged with the firing drive system, and when the switch drum  27500  is in its second position, the articulation drive system is operably disengaged from the firing drive system.  FIG. 132  illustrates the shaft assembly  27200  when the switch drum  27500  is in its first position. When the switch drum  27500  is in its first position, the sensing fork  27700  vibrates at a higher frequency, as it is not experiencing vibrational damping from contact with the inwardly-facing projections  27502  of the switch drum  27500 . When the sensing fork  27700  is being driven by the output actuator, the input transducer  27602  will detect the frequency of the sensing fork  27700  and subsequently communicate with the shaft circuit board  27610  to determine that the articulation drive system is engaged with the firing drive system.  FIG. 133  illustrates the shaft assembly  27200  when the switch drum  27500  is in its second position. When the switch drum  27500  is in its second position, the sensing fork  27700  vibrates at a lower frequency, as it is experiencing vibrational damping due to contact with the inwardly-facing projections  27502  of the switch drum  27500 . When the sensing fork  27700  is being driven by the output actuator, the input transducer  27602  will detect the frequency of the sensing fork  27700  and subsequently communicate with the shaft circuit board  27610  to determine that the articulation drive system is disengaged from the firing drive system. 
     While the above-described system monitors the state of the articulation drive system, it is also envisioned that the above-described system can be adapted to other forms of detection throughout the shaft and the handle of the surgical instrument such as, for example, monitoring the state of the closure and/or staple firing drive systems. 
     As mentioned above, the shaft assembly  28200  depicted in  FIGS. 134-136  is similar in many respects to the shaft assembly  200  depicted in  FIGS. 8-12 . The shaft assembly  28200  comprises an articulation drive system, an end effector closure system, and a stapling firing system. Similar to the above, the articulation drive system is selectively engageable with the staple firing system. When the articulation drive system is operably engaged with the staple firing system, the staple firing system can be used to drive the articulation drive system and articulate the end effector. When the articulation is not operably engaged with the staple firing system, the articulation drive system is not drivable by the staple firing system, and the staple firing system can be used to perform a staple firing stroke. 
     Although not shown, the shaft assembly  28200  comprises a nozzle housing  28201  which is similar to the nozzle housing  203  depicted in  FIG. 10 . The shaft assembly  28200  further comprises a rotatable switch drum  28500  and a chassis mounting flange  28242 . The switch drum  28500  is rotatable between a first position and a second position relative to the chassis mounting flange  28242 . When the switch drum  28500  is in its first position, the articulation drive system is operably engaged with the firing drive system. Thus, when the switch drum  28500  is in its first position, the firing drive system may drive the articulation drive system to articulate the end effector of the shaft assembly  28200 . When the switch drum  28500  is in its second position, the articulation drive system is operably disengaged from the firing drive system. Thus, when the switch drum  28500  is in its second position, the firing drive system will not drive the articulation drive system. 
     Referring primarily to  FIG. 134 , the switch drum  28500  comprises a switch drum collar  28505  located on a proximal end thereof. The switch drum collar  28505  comprises one or more switch collar windows  28510 . The switch collar windows  28510  are arranged in an annular pattern along the switch drum collar  28505 . The switch collar windows  28510  are evenly spaced apart, although any suitable arrangement can be used. The nozzle  28201  comprises an annular, inward projection  28205  positioned distal to the switch drum collar  28505 . A proximal surface of the inward projection  28205  comprises one or more dark markings  28210 . The dark markings  28210  are arranged in an annular pattern along the proximal surface of the inward projection  28205 . The dark markings  28210  are spaced apart at a distance corresponding to the spacing of the switch collar windows  28510 , although any suitable arrangement can be used. The dark markings  28210  can be laser-etched, printed in ink, and/or formed from any suitable material on the proximal surface of the inward projection  28205 . 
     The shaft assembly  28200  further comprises a shaft circuit board  28610  comprising a barcode scanning element  28612  configured to detect the presence or absence of the dark markings  28210  in the switch collar windows  28510 . The barcode scanning element  28612  converts the amount of dark markings  28210  within the switch collar windows  28510  into an electrical signal. A microprocessor on the shaft circuit board  28610  is configured to receive the electrical signal from the barcode scanning element  28612  and is configured monitor an operating state or mode of the shaft assembly  28200  based on the detected amount of dark markings  28210  in the switch collar windows  28510 , as discussed below. 
     An exemplary operating state that can be monitored through the barcode scanning element  28612  is an articulation state. As discussed above, when the switch drum  28500  is in its first position, the articulation drive system is operably engaged with the firing drive system, and when the switch drum  28500  is in its second position, the articulation drive system is operably disengaged from the firing drive system.  FIG. 135  illustrates the shaft assembly  28200  when the switch drum  28500  is in its first position. When the switch drum  28500  is in its first position, the dark markings  28210  are not visible through the switch collar windows  28510 . In such instances, the barcode scanner element  28612  will detect the absence of dark markings  28210  and subsequently communicate with the shaft circuit board  28610  which can determine that the articulation drive system is engaged with the firing drive system.  FIG. 136  illustrates the shaft assembly  28200  when the switch drum  28500  is in its second position. When the switch drum  28500  is in its second position, the dark markings  28210  are visible through the switch collar windows  28510 . In such instances, the barcode scanner element  28612  will detect the presence of dark markings  28210  and subsequently communicate with the shaft circuit board  28610  which can determine that the articulation drive system is disengaged from the firing drive system. 
     Further to the above, the shaft circuit board  28610  comprises a processor, such as a microprocessor, for example, which is configured to assess the state of the shaft assembly  28200 . In some instances, the switch drum  28500  is not completely in its first position or its second position. In such instances, only a portion of the dark markings  28210  will be visible in the switch collar windows  28510 . The barcode scanning element  28612  is configured to detect this partial overlap and the microprocessor is configured to evaluate the signal output by the barcode scanning element  28612  to assess whether or not the switch drum  28500  has been sufficiently rotated to disengage the articulation drive system from the staple firing system. In various instances, the microprocessor can utilize a threshold to make this decision. For instance, when at least half of the switch collar windows  28510  have been darkened by the dark markings  28210 , for example, the microprocessor can assess and verify that the shaft assembly  28200  has been sufficiently switched and that the articulation drive system is no longer engaged with the staple firing system. If less than the threshold has been darkened, the microprocessor can determine that the articulation drive system has not been sufficiently decoupled from the staple firing system. 
     As discussed above, the processor, or controller, of a shaft assembly can be used to verify or confirm that the shaft assembly has been switched over from an end effector articulation state to a staple firing state. In the instances where the processor or controller is unable to verify or confirm that the shaft assembly has been switched over, even though other sensors suggest that it has been, the processor or controller can warn the user of the surgical system and/or prevent the use of the shaft assembly. In such instances, the user can either resolve the issue or replace the shaft assembly. 
     While the above-described system monitors the state of the articulation drive system, it is also envisioned that the above-described system can be adapted to other forms of detection throughout the shaft and the handle of the surgical instrument such as, for example, monitoring the state of the closure and/or staple firing drive systems. 
       FIGS. 137-141  depict a surgical cutting and fastening instrument  29010  which is similar in many respects to the surgical instrument  10  shown in  FIG. 1 . The instrument  29010  comprises a handle  29014  that is configured to be grasped, manipulated, and actuated by a clinician. The handle  29014  includes a frame  29020  and a housing  29012 , and is configured to be operably attached to an interchangeable shaft assembly  29200 . The shaft assembly  29200  includes a surgical end effector  300  ( FIG. 1 ), or any other suitable end effector, which is configured to perform one or more surgical tasks or procedures. As discussed in greater detail below, the handle  29014  operably supports a plurality of drive systems therein that are configured to generate and transmit various control motions to the shaft assembly  29200  operably attached thereto. 
     Further to the above, the handle  29014  includes a frame  29020  that supports the plurality of drive systems. In at least one form, the frame  29020  supports a firing drive system that is configured to transmit a firing motion to the shaft assembly  29200 . The firing drive system comprises an electric motor  82  ( FIG. 4 ), or any other suitable electric motor, configured to drive a longitudinal drive member  29120  axially in proximal and/or distal directions. Alternatively, the handle  29014  can comprise a trigger which is used to manually drive and/or retract the drive member  29120 . In any event, the drive member  29120  comprises an attachment cradle  29126  defined in the distal end  29125  thereof which is configured to receive a portion of a shaft firing member  29220  of the shaft assembly  29200 . Referring primarily to  FIGS. 138 and 139 , the shaft firing member  29220  comprises an attachment lug  29226  formed on the proximal end thereof. When the shaft assembly  29200  is coupled to the handle  29014 , the attachment lug  29226  is received in the attachment cradle  29126 . The attachment lug  29226  comprises a larger diameter than that of the longitudinal body  29222  of the shaft firing member  29220  to facilitate the engagement of the shaft firing member  29220  with the firing shaft attachment cradle  29126 . 
     The shaft assembly  29200  comprises a shaft frame  29240  which is fixedly mountable to an attachment flange  29700  defined on the distal end of the handle frame  29020 . The shaft frame  29240  includes one or more tapered attachment portions  29244  formed thereon that are adapted to be received within corresponding dovetail slots  29702  defined within the attachment flange  29700  of the handle frame  29020 . Each dovetail slot  29702  is tapered, or somewhat V-shaped, to seatingly receive the attachment portions  29244  therein. To couple the shaft assembly  29200  to the handle  29014 , a clinician can position the frame  29240  of the shaft assembly  29200  above or adjacent to the attachment flange  29700  of the handle frame  29020  such that the tapered attachment portions  29244  defined on the shaft frame  29240  are aligned with the dovetail slots  29702  in the handle frame  29020 . The clinician can then move the shaft assembly  29200  along an installation axis IA-IA that is perpendicular to the shaft axis SA-SA to seat the attachment portions  29244  in the corresponding dovetail slots  29702 . In doing so, the shaft attachment lug  29226  defined on the shaft firing member  29220  will also be seated in the firing shaft attachment cradle  29126  defined in the handle drive member  29120 . 
     The shaft assembly  29200  further includes a latch system  29710  configured to releaseably couple the shaft assembly  29200  to the handle  29014 . Referring primarily to  FIG. 137 , the latch system  29710  comprises a housing latch  29712  configured to engage the handle housing  29012  and releaseably prevent the shaft assembly  29200  from being detached from the handle  29014 . Similar to the housing latch of the surgical instrument  10 , the housing latch  29712  can be depressed to unlock the shaft assembly  29200  from the handle  29014  so that the shaft assembly  29200  can be disassembled from the handle  29014 . The latch system  29710  further includes a firing latch  29720  that is configured to hold the shaft firing member  29220  in position prior to the shaft assembly  29200  being assembled to the handle  29014  and/or during the assembly of the shaft assembly  29200  to the handle  29014 . The firing latch  29720  is movably coupled to the shaft frame  29240  by a pivot  29722 . When the shaft assembly  29200  is unattached to the handle  29014 , referring primarily to  FIGS. 138 and 140 , the firing latch  29720  is engaged with the shaft firing member  29220 . More specifically, an end of the firing latch  29720  is biased into a recess  29221  defined in the longitudinal body  29222  of the firing member  29220  by a biasing member  29730  such that the end of the latch  29720  is positioned in front of a distal shoulder  29223  defined on the lug  29226 . The biasing member  29730  comprises a spring, for example, which is positioned in a cavity  29731  defined in the shaft frame  29420  and is compressed between the shaft frame  29420  and the firing latch  29720 . When the firing latch  29720  is positioned in front of the lug  29226 , as illustrated in  FIG. 138 , the firing latch  29720  prevents the firing member  29220  from being advanced distally inadvertently. 
     As the shaft assembly  29200  is being attached to the handle  29014 , referring primarily to  FIGS. 139 and 141 , the firing latch  29720  contacts the handle drive member  29120  and rotates upwardly out of the recess  29221  defined in the shaft firing member  29220 . As a result, the end of the firing latch  29720  is no longer positioned in front of the distal shoulder  29223  of the lug  29226 . In such instances, the shaft firing member  29220  has become unlocked as the firing latch  29720  can no longer prevent the shaft firing member  29220  from being moved distally. Notably, the shaft firing member  29220  is operably engaged with the handle drive member  29120  when the shaft firing member  29220  is unlocked such that the shaft firing member  29220  can be moved longitudinally by the handle drive member  29210 . In various instances, the shaft firing member  29220  is unlocked at the same time that the shaft firing member  29220  is operably engaged with the handle drive member  29210 ; however, the shaft firing member  29220  could be unlocked just before the shaft firing member  29220  is operably coupled with the handle drive member  29210 . In either event, once unlocked and engaged with the handle drive member  29210 , the shaft firing member  29220  can be used to articulate the end effector  300  of the shaft assembly  29200  and/or perform a staple firing stroke. 
     As discussed above, the firing latch  29720  is moved from an unlocked position to a locked position when the firing latch  29270  contacts the handle drive member  29210 . In various alternative embodiments, the handle frame  29020  can comprise a shoulder, for example, which can rotate the firing latch  29720  into its unlocked position as the shaft assembly  29200  is being assembled to the handle  29014 . 
     When the shaft assembly  29200  is disassembled from the handle  29014 , the latch  29720  is moved out of contact with the handle drive member  29210 . In such instances, the biasing member  29730  biases the firing latch  29720  back into its locked position and can hold the shaft firing member  29220  in position while the shaft assembly  29200  is being disassembled from the handle  29104  and/or after the shaft assembly  29200  has been completely detached—assuming that the shaft firing member  29220  has been returned to its home position ( FIGS. 138 and 139 ). In various instances, further to the above, the shaft assembly  29200  and/or handle  29014  are configured such that shaft assembly  29200  cannot be detached from the handle  29014  unless the shaft firing member  29220  has been returned to its home position ( FIGS. 138 and 139 ). In such instances, the entire surgical instrument  29010  is reset to its home state before the shaft assembly  29200  can be removed which, as a result, makes it more convenient for a clinician to assemble another shaft assembly to the handle  29014 . That said, various embodiments are envisioned in which the shaft assembly  29200  could be removed from the handle  29014  before the surgical instrument  29010  is returned to its home state; however, in such instances, the firing latch  29720  may not hold the shaft firing member  29220  in position while the shaft assembly  29200  is unattached to the handle  29014 . 
       FIGS. 142-147  depict a shaft assembly  30200  which is similar to the shaft assembly  29200  in many respects. Similar to the above, the shaft assembly  30200  comprises a latch system  30710  configured to hold the shaft firing member  29220  in position while the shaft assembly  30200  is not attached to the handle  29014  and/or is being attached to the handle  29014 , but is configured to release the shaft firing member  29220  once the shaft assembly  30200  is assembled to the handle  29014 . Referring primarily to  FIGS. 143 and 146 , the latch system  30710  includes a firing lock  30720 . The firing lock  30720  comprises a central gripping portion  30721  and lateral mounting portions  30722 . The central gripping portion  30721  comprises lateral sidewalls  30723  which are configured to resiliently engage, or grip, the recess portion  29221  of the shaft firing member  29220 . The distance between the lateral sidewalls  30723  is the same as or less than the diameter of the recess portion  29221  such that the shaft firing member  29220  fits snugly within the central gripping portion  30721 . The lateral mounting portions  30722  are fixedly embedded in the shaft frame  29240  such that the lateral mounting portions  30722  do not move, or at least substantially move, relative to the shaft frame  29240 . That said, the other portions of the firing lock  30720  are configured to move and/or deflect when the shaft assembly  30200  is assembled to the handle  29014 , as discussed in greater detail below. 
     Further to the above, referring again to  FIGS. 143 and 146 , the firing lock  30720  is releaseably engageable with the recess portion  29221  of the shaft firing member  29220 . In such instances, the central gripping portion  30721  is positioned intermediate the distal shoulder  29223  of the lug  29226  and a distal end wall  29225  of the recess portion  29221  when the firing lock  30720  is engaged with the shaft firing member  29220 . Moreover, in such instances, the firing lock  30720  prevents the shaft firing member  29220  from moving proximally and/or distally prior to being assembled to the handle  29014 . The central gripping portion  30721  of the firing lock  30720  is sized and configured such that it is closely received between the lug shoulder  29223  and the distal end wall  29225 . As a result, very little relative movement, if any, is possible between the shaft firing member  29220  and the firing lock  30720  when the firing lock  30720  is engaged with the shaft firing member  29220 . When the shaft assembly  30200  is assembled to the handle  29014 , the firing lock  30720  contacts the handle drive member  29120  and then deflects as illustrated in  FIGS. 144 and 147 . In such instances, the firing lock  30720  becomes disengaged from the shaft firing member  29220 . 
     Further to the above, the firing lock  30720  releases, or unlocks, the shaft firing member  29220  as the shaft firing member  29220  is operably coupled with the handle drive member  29120 ; however, the shaft firing member  29220  could be unlocked just before the shaft firing member  29220  is operably coupled with the handle drive member  29210 . In either event, once unlocked and engaged with the handle drive member  29210 , the shaft firing member  29220  can be used to articulate the end effector  300  of the shaft assembly  29200  and/or perform a staple firing stroke, as illustrated in  FIG. 145 . Notably, the shaft firing member  29220  and the handle drive member  29120  move relative to the firing lock  30720  which remains stationary during the staple firing stroke. When the shaft assembly  30200  is disassembled from the handle  29014 , the firing lock  30720  is moved out of contact with the handle drive member  29210 . In such instances, the firing lock  30720  resiliently returns to its original locked configuration as illustrated in  FIGS. 143 and 146 . Assuming that the shaft firing member  29220  has been returned to its home position ( FIGS. 143 and 144 ) when the shaft assembly  30200  is disassembled from the handle  29014 , the firing lock  30720  can once retain the shaft firing member  29220  in position. 
     As discussed above, it can be desirable to have the actuation systems of a surgical instrument in their home state when a replaceable shaft assembly of the surgical instrument is attached to and/or detached from the handle. In various instances, for example, it can be difficult for a clinician to properly connect the staple firing sub-system of the shaft assembly with the staple firing sub-system of the handle unless they are in their home states. In some such instances, the shaft assembly can be attached to the handle even though the corresponding staple firing sub-systems are not properly connected—a condition which may not be readily apparent to the clinician. In various embodiments, a surgical instrument can be configured to assess the status of a shaft assembly once it has been attached to the handle. In at least one such embodiment, the surgical instrument comprises a controller including a microprocessor and a memory device configured to run a software module which, among other things, evaluates whether or not the shaft assembly is properly connected to the handle, as discussed in greater detail below. 
       FIG. 148  depicts an exemplary software module  31100  for use with a controller of an interchangeable shaft assembly such as, for example, any of the controllers disclosed herein. In various instances, the interchangeable shaft assemblies  29200  and  30200 , discussed above, comprise such a controller. The controller may comprise one or more processors and/or memory units which may store a number of software modules such as, for example, the module  31100 . Although certain modules and/or blocks of the interchangeable shaft assembly and surgical instrument handle may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used. Further, although various instances may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components such as, for example, processors, DSPs, PLDs, ASICs, circuits, registers and/or software components such as, for example, programs, subroutines, logic and/or combinations of hardware and software components. 
     Upon coupling the interchangeable shaft assembly  29200 , for example, to the handle  29014 , an interface may facilitate communication between the controller and a memory to execute the module  31100 . After coupling the interchangeable shaft assembly  29200  to the handle  29014 , referring again to  FIG. 148 , the module  31100  is configured to detect the position of the drive member  29120  in the handle  29014 . One or more sensor circuits including sensors, such as Hall Effect sensors, for example, in signal communication with the controller could be used to detect the position of handle driver member  29120 . If the handle drive member  29120  is not in its home position, one or more functions of the surgical instrument are disabled. For instance, the articulation of the end effector, the closing of the end effector, and/or the performing a staple firing stroke can be prevented. Deactivating, or locking out, one or more of these systems can be accomplished by decoupling electrical power to such systems, for example. The software module  31100  will routinely detect the position of the longitudinal drive member  29120  until it is determined to be in its home position, thus providing the surgical instrument and/or clinician with opportunity to remedy the locked out condition. If the handle drive member  29120  is detected as being in its home position, the software module  31100  then detects the position of the shaft firing member  29220 , as discussed in greater detail below. 
     As discussed above, the shaft firing member  29220  is operably coupled to the handle drive member  29120  when the shaft assembly  29200  is assembled to the handle  29014 . 
     Although any suitable coupling arrangement could be used, the handle drive member  29120  comprises an attachment cradle  29126  configured to receive a portion of the shaft firing member  29220 . One or more sensor circuits including sensors, such as proximity sensors, for example, could be used to detect the presence of shaft firing member  29220  in the attachment cradle  29126 . If the module  31100  determines that the firing member  29220  is not in the attachment cradle  29126 , one or more functions of the surgical instrument are disabled. For instance, the articulation of the end effector, the closing of the end effector, and/or the performing a staple firing stroke can be prevented. Deactivating, or locking out, one or more of these systems can be accomplished by decoupling electrical power to such systems, for example. Other systems for detecting the position, and/or proper attachment, of the shaft firing member  29220  can be used. The software module  31100  will routinely monitor the firing member  29220  until it determines that the firing member  29220  is suitably attached to the shaft drive member  29120 . 
     Once the software module  31100  determines that the shaft firing member  29220  is suitably coupled to the handle drive member  29120 , the software module  31100  then determines if an articulation switch has been activated. The articulation switch evaluates whether or not the articulation system has been operably coupled to, is currently coupled to, and/or has been driven by the staple firing system. Such information can be stored in a memory device within the shaft assembly and/or handle. In order to determine if the articulation drive system has been engaged with the staple firing system, for instance, the software module  31100  analyzes the memory device. If the articulation drive system has never been engaged with the staple firing system, and the articulation switch was never activated, the software module  31100  is configured to disable one or more functions of the surgical instrument. For instance, the articulation of the end effector, the closing of the end effector, and/or the performing a staple firing stroke can be prevented. Deactivating, or locking out, one or more of these systems can be accomplished by decoupling electrical power to such systems, for example. If the articulation drive system has previously been engaged, or sensed as having been engaged, with the staple firing system, the software module  31100  permits the user to proceed with a desired operating function of the surgical instrument such as, for example, articulating the end effector, performing a staple firing stroke, and/or closing the end effector. 
     Further to the above, other software modules can be used. For instance, the software module  31100  can perform two or more of the above-discussed steps at the same time. In at least one such instance, the software module  31100  can contemporaneously assess the position of the handle drive member  29120 , whether the shaft firing member  29220  is properly coupled to the handle drive member  29120 , and/or whether the end effector articulation system has been previously driven by the staple firing system, for example. 
     The entire disclosures of: 
     U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE, which issued on Apr. 4, 1995; 
     U.S. Pat. No. 7,000,818, entitled SURGICAL STAPLING INSTRUMENT HAVING SEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, which issued on Feb. 21, 2006; 
     U.S. Pat. No. 7,422,139, entitled MOTOR-DRIVEN SURGICAL CUTTING AND FASTENING INSTRUMENT WITH TACTILE POSITION FEEDBACK, which issued on Sep. 9, 2008; 
     U.S. Pat. No. 7,464,849, entitled ELECTRO-MECHANICAL SURGICAL INSTRUMENT WITH CLOSURE SYSTEM AND ANVIL ALIGNMENT COMPONENTS, which issued on Dec. 16, 2008; 
     U.S. Pat. No. 7,670,334, entitled SURGICAL INSTRUMENT HAVING AN ARTICULATING END EFFECTOR, which issued on Mar. 2, 2010; U.S. Pat. No. 7,753,245, entitled SURGICAL STAPLING INSTRUMENTS, which issued on Jul. 13, 2010; 
     U.S. Pat. No. 8,393,514, entitled SELECTIVELY ORIENTABLE IMPLANTABLE FASTENER CARTRIDGE, which issued on Mar. 12, 2013; 
     U.S. patent application Ser. No. 11/343,803, entitled SURGICAL INSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Pat. No. 7,845,537; 
     U.S. patent application Ser. No. 12/031,573, entitled SURGICAL CUTTING AND FASTENING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008; 
     U.S. patent application Ser. No. 12/031,873, entitled END EFFECTORS FOR A SURGICAL CUTTING AND STAPLING INSTRUMENT, filed Feb. 15, 2008, now U.S. Pat. No. 7,980,443; 
     U.S. patent application Ser. No. 12/235,782, entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT, now U.S. Pat. No. 8,210,411; 
     U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICAL CUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM, now U.S. Pat. No. 8,608,045; 
     U.S. patent application Ser. No. 12/647,100, entitled MOTOR-DRIVEN SURGICAL CUTTING INSTRUMENT WITH ELECTRIC ACTUATOR DIRECTIONAL CONTROL ASSEMBLY, filed Dec. 24, 2009, now U.S. Pat. No. 8,220,688; 
     U.S. patent application Ser. No. 12/893,461, entitled STAPLE CARTRIDGE, filed Sep. 29, 2012, now U.S. Pat. No. 8,733,613; 
     U.S. patent application Ser. No. 13/036,647, entitled SURGICAL STAPLING INSTRUMENT, filed Feb. 28, 2011, now U.S. Pat. No. 8,561,870; 
     U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat. No. 9,072,535; 
     U.S. patent application Ser. No. 13/524,049, entitled ARTICULATABLE SURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, filed on Jun. 15, 2012, now U.S. Pat. No. 9,101,358; 
     U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat. No. 9,345,481; 
     U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Patent Application Publication No. 2014/0263552; 
     U.S. Patent Application Publication No. 2007/0175955, entitled SURGICAL CUTTING AND FASTENING INSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM, filed Jan. 31, 2006; and 
     U.S. Patent Application Publication No. 2010/0264194, entitled SURGICAL STAPLING INSTRUMENT WITH AN ARTICULATABLE END EFFECTOR, filed Apr. 22, 2010, are hereby incorporated by reference herein. 
     In accordance with various embodiments, the surgical instruments described herein may comprise one or more processors (e.g., microprocessor, microcontroller) coupled to various sensors. In addition, to the processor(s), a storage (having operating logic) and communication interface, are coupled to each other. 
     The processor may be configured to execute the operating logic. The processor may be any one of a number of single or multi-core processors known in the art. The storage may comprise volatile and non-volatile storage media configured to store persistent and temporal (working) copy of the operating logic. 
     In various embodiments, the operating logic may be configured to process the collected biometric associated with motion data of the user, as described above. In various embodiments, the operating logic may be configured to perform the initial processing, and transmit the data to the computer hosting the application to determine and generate instructions. For these embodiments, the operating logic may be further configured to receive information from and provide feedback to a hosting computer. In alternate embodiments, the operating logic may be configured to assume a larger role in receiving information and determining the feedback. In either case, whether determined on its own or responsive to instructions from a hosting computer, the operating logic may be further configured to control and provide feedback to the user. 
     In various embodiments, the operating logic may be implemented in instructions supported by the instruction set architecture (ISA) of the processor, or in higher level languages and compiled into the supported ISA. The operating logic may comprise one or more logic units or modules. The operating logic may be implemented in an object oriented manner. The operating logic may be configured to be executed in a multi-tasking and/or multi-thread manner. In other embodiments, the operating logic may be implemented in hardware such as a gate array. 
     In various embodiments, the communication interface may be configured to facilitate communication between a peripheral device and the computing system. The communication may include transmission of the collected biometric data associated with position, posture, and/or movement data of the user&#39;s body part(s) to a hosting computer, and transmission of data associated with the tactile feedback from the host computer to the peripheral device. In various embodiments, the communication interface may be a wired or a wireless communication interface. An example of a wired communication interface may include, but is not limited to, a Universal Serial Bus (USB) interface. An example of a wireless communication interface may include, but is not limited to, a Bluetooth interface. 
     For various embodiments, the processor may be packaged together with the operating logic. In various embodiments, the processor may be packaged together with the operating logic to form a System in Package (SiP). In various embodiments, the processor may be integrated on the same die with the operating logic. In various embodiments, the processor may be packaged together with the operating logic to form a System on Chip (SoC). 
     Various embodiments may be described herein in the general context of computer executable instructions, such as software, program modules, and/or engines being executed by a processor. Generally, software, program modules, and/or engines include any software element arranged to perform particular operations or implement particular abstract data types. Software, program modules, and/or engines can include routines, programs, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. An implementation of the software, program modules, and/or engines components and techniques may be stored on and/or transmitted across some form of computer-readable media. In this regard, computer-readable media can be any available medium or media useable to store information and accessible by a computing device. Some embodiments also may be practiced in distributed computing environments where operations are performed by one or more remote processing devices that are linked through a communications network. In a distributed computing environment, software, program modules, and/or engines may be located in both local and remote computer storage media including memory storage devices. A memory such as a random access memory (RAM) or other dynamic storage device may be employed for storing information and instructions to be executed by the processor. The memory also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. 
     Although some embodiments may be illustrated and described as comprising functional components, software, engines, and/or modules performing various operations, it can be appreciated that such components or modules may be implemented by one or more hardware components, software components, and/or combination thereof. The functional components, software, engines, and/or modules may be implemented, for example, by logic (e.g., instructions, data, and/or code) to be executed by a logic device (e.g., processor). Such logic may be stored internally or externally to a logic device on one or more types of computer-readable storage media. In other embodiments, the functional components such as software, engines, and/or modules may be implemented by hardware elements that may include processors, microprocessors, circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, and so forth), integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, chips, microchips, chip sets, and so forth. 
     Examples of software, engines, and/or modules may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (API), instruction sets, computing code, computer code, code segments, computer code segments, words, values, symbols, or any combination thereof. Determining whether an embodiment is implemented using hardware elements and/or software elements may vary in accordance with any number of factors, such as desired computational rate, power levels, heat tolerances, processing cycle budget, input data rates, output data rates, memory resources, data bus speeds and other design or performance constraints. 
     One or more of the modules described herein may comprise one or more embedded applications implemented as firmware, software, hardware, or any combination thereof. One or more of the modules described herein may comprise various executable modules such as software, programs, data, drivers, application program interfaces (APIs), and so forth. The firmware may be stored in a memory of the controller  2016  and/or the controller  2022  which may comprise a nonvolatile memory (NVM), such as in bit-masked read-only memory (ROM) or flash memory. In various implementations, storing the firmware in ROM may preserve flash memory. The nonvolatile memory (NVM) may comprise other types of memory including, for example, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or battery backed random-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM). 
     In some cases, various embodiments may be implemented as an article of manufacture. The article of manufacture may include a computer readable storage medium arranged to store logic, instructions and/or data for performing various operations of one or more embodiments. In various embodiments, for example, the article of manufacture may comprise a magnetic disk, optical disk, flash memory or firmware containing computer program instructions suitable for execution by a general purpose processor or application specific processor. The embodiments, however, are not limited in this context. 
     The functions of the various functional elements, logical blocks, modules, and circuits elements described in connection with the embodiments disclosed herein may be implemented in the general context of computer executable instructions, such as software, control modules, logic, and/or logic modules executed by the processing unit. Generally, software, control modules, logic, and/or logic modules comprise any software element arranged to perform particular operations. Software, control modules, logic, and/or logic modules can comprise routines, programs, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. An implementation of the software, control modules, logic, and/or logic modules and techniques may be stored on and/or transmitted across some form of computer-readable media. In this regard, computer-readable media can be any available medium or media useable to store information and accessible by a computing device. Some embodiments also may be practiced in distributed computing environments where operations are performed by one or more remote processing devices that are linked through a communications network. In a distributed computing environment, software, control modules, logic, and/or logic modules may be located in both local and remote computer storage media including memory storage devices. 
     Additionally, it is to be appreciated that the embodiments described herein illustrate example implementations, and that the functional elements, logical blocks, modules, and circuits elements may be implemented in various other ways which are consistent with the described embodiments. Furthermore, the operations performed by such functional elements, logical blocks, modules, and circuits elements may be combined and/or separated for a given implementation and may be performed by a greater number or fewer number of components or modules. As will be apparent to those of skill in the art upon reading the present disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several aspects without departing from the scope of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order which is logically possible. 
     It is worthy to note that any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is comprised in at least one embodiment. The appearances of the phrase “in one embodiment” or “in one aspect” in the specification are not necessarily all referring to the same embodiment. 
     Unless specifically stated otherwise, it may be appreciated that terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, such as a general purpose processor, a DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein that manipulates and/or transforms data represented as physical quantities (e.g., electronic) within registers and/or memories into other data similarly represented as physical quantities within the memories, registers or other such information storage, transmission or display devices. 
     It is worthy to note that some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. These terms are not intended as synonyms for each other. For example, some embodiments may be described using the terms “connected” and/or “coupled” to indicate that two or more elements are in direct physical or electrical contact with each other. The term “coupled,” however, also may mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. With respect to software elements, for example, the term “coupled” may refer to interfaces, message interfaces, application program interface (API), exchanging messages, and so forth. 
     It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. 
     The disclosed embodiments have application in conventional endoscopic and open surgical instrumentation as well as application in robotic-assisted surgery. 
     Embodiments of the devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. Embodiments may, in either or both cases, be reconditioned for reuse after at least one use. Reconditioning may include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, embodiments of the device may be disassembled, and any number of the particular pieces or parts of the device may be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, embodiments of the device may be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device may utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     By way of example only, embodiments described herein may be processed before surgery. First, a new or used instrument may be obtained and when necessary cleaned. The instrument may then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument may then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation may kill bacteria on the instrument and in the container. The sterilized instrument may then be stored in the sterile container. The sealed container may keep the instrument sterile until it is opened in a medical facility. A device also may be sterilized using any other technique known in the art, including but not limited to beta or gamma radiation, ethylene oxide, or steam. 
     One skilled in the art will recognize that the herein described components (e.g., operations), devices, objects, and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration modifications are contemplated. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be taken limiting. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations are not expressly set forth herein for sake of clarity. 
     The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated also can be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality, and any two components capable of being so associated also can be viewed as being “operably couplable,” to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable, and/or wirelessly interacting components, and/or logically interacting, and/or logically interactable components. 
     Some aspects may be described using the expression “coupled” and “connected” along with their derivatives. It should be understood that these terms are not intended as synonyms for each other. For example, some aspects may be described using the term “connected” to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some aspects may be described using the term “coupled” to indicate that two or more elements are in direct physical or electrical contact. The term “coupled,” however, also may mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. 
     In some instances, one or more components may be referred to herein as “configured to,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that “configured to” can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise. 
     While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that when a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. 
     In addition, even when a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.” 
     With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. 
     In summary, numerous benefits have been described which result from employing the concepts described herein. The foregoing description of the one or more embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more embodiments were chosen and described in order to illustrate principles and practical application to thereby enable one of ordinary skill in the art to utilize the various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the claims submitted herewith define the overall scope. 
     EXAMPLES 
     Various aspects of the subject matter described herein are set out in the following numbered examples: 
     Example 1. A surgical instrument comprising a handle, a shaft and an end effector comprising a staple cartridge, wherein the end effector is articulatable relative to the shaft. The surgical instrument further comprises a first sensor configured to detect a condition of the surgical instrument and a second sensor configured to detect the condition, wherein the condition includes one of an end effector articulation mode and a staple firing operating mode. The surgical instrument further comprises a processor, wherein the first sensor and the second sensor are in signal communication with the processor, wherein the processor receives a first signal from the first sensor, wherein the processor receives a second signal from the second sensor, wherein the processor is configured to utilize the first signal and the second signal to determine the condition, and wherein the processor is configured to communicate instructions to the surgical instrument in view of the condition. 
     Example 2. The surgical instrument of Example 1, wherein the first sensor comprises a Hall Effect sensor. 
     Example 3. The surgical instrument of Example 1, wherein the first sensor comprises a moisture sensor. 
     Example 4. The surgical instrument of Example 1, wherein the first sensor comprises an accelerometer. 
     Example 5. The surgical instrument of Example 1, wherein the first sensor comprises a chemical exposure sensor. 
     Example 6. The surgical instrument of Example 1, wherein the staple cartridge comprises staples removably stored therein. 
     Example 7. A surgical instrument configured for use in a surgical procedure, comprising a housing, a first sensor configured to detect a condition of the surgical instrument, and a second sensor configured to detect the condition. The surgical instrument further comprises a processor, wherein the processor is located within the housing, wherein the first sensor and the second sensor are in signal communication with the processor, wherein the processor receives a first signal from the first sensor, wherein the processor receives a second signal from the second sensor, wherein the processor is configured to utilize the first signal and the second signal to determine the condition, and wherein the processor is configured to communicate instructions to the surgical instrument during the surgical procedure in view of the condition. 
     Example 8. The surgical instrument of Example 7, wherein the first sensor comprises a Hall Effect sensor. 
     Example 9. The surgical instrument of Example 7, wherein the first sensor comprises a moisture sensor. 
     Example 10. The surgical instrument of Example 7, wherein the first sensor comprises an accelerometer. 
     Example 11. The surgical instrument of Example 7, wherein the first sensor comprises a chemical exposure sensor. 
     Example 12. The surgical instrument of Example 7, wherein the surgical instrument further comprises a staple cartridge. 
     Example 13. A surgical instrument, comprising a housing comprising an internal housing, a first sensor system, a second sensor system, and a controller positioned within the internal volume of the housing. The first sensor system and the second sensor system are in signal communication with the controller, wherein the controller is configured to receive a first signal from the first sensor system, wherein the controller is configured to receive a second signal from the second sensor system, wherein the controller is configured to utilize the first signal and the second signal to determine a condition of the surgical instrument, and wherein the controller is configured to communicate instructions to the surgical instrument in response to the condition. 
     Example 14. The surgical instrument of Example 13, wherein the first sensor system comprises a Hall Effect sensor. 
     Example 15. The surgical instrument of Example 13, wherein the first sensor system comprises a moisture sensor. 
     Example 16. The surgical instrument of Example 13, wherein the first sensor system comprises an accelerometer. 
     Example 17. The surgical instrument of Example 13, wherein the first sensor system comprises a chemical exposure sensor. 
     Example 18. The surgical instrument of Example 13, wherein the surgical instrument further comprises a staple cartridge.