Patent Publication Number: US-2022218382-A1

Title: Feedback algorithms for manual bailout systems for surgical instruments

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 16/587,803, entitled FEEDBACK ALGORITHMS FOR MANUAL BAILOUT SYSTEMS FOR SURGICAL INSTRUMENTS, filed Sep. 30, 2019, now U.S. Patent Application Publication No. 2020/0093506, which is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 16/041,145, entitled FEEDBACK ALGORITHMS FOR MANUAL BAILOUT SYSTEMS FOR SURGICAL INSTRUMENTS, filed Jul. 20, 2018, now U.S. Patent Application Publication No. 2018/0333169, which is a continuation application claiming priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 14/226,093, entitled FEEDBACK ALGORITHMS FOR MANUAL BAILOUT SYSTEMS FOR SURGICAL INSTRUMENTS, filed Mar. 26, 2014, which issued on Jul. 24, 2018 as U.S. Pat. No. 10,028,761, 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 ; and 
         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; and 
         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; and 
         FIG. 68C  is a table listing various specifications of a magnetoresistive sensor according to various embodiments of the present disclosure. 
     
    
    
     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. 9,358,033; 
     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. Pat. No. 9,883,860; 
     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. Pat. No. 9,808,244; 
     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. Pat. No. 9,888,919. 
     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. 14/226,142, entitled SURGICAL INSTRUMENT COMPRISING A SENSOR SYSTEM, now U.S. Pat. No. 9,913,642; 
     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. Pat. No. 9,826,977; 
     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. 2015/0272580; 
     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. Pat. No. 10,013,049; 
     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. 14/226,116, 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. Pat. No. 9,820,738; 
     U.S. patent application Ser. No. 14/226,126, entitled INTERFACE SYSTEMS FOR USE WITH SURGICAL INSTRUMENTS, now U.S. Pat. No. 10,004,497; 
     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. Pat. No. 9,804,618; 
     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. Pat. No. 10,201,364. 
     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 . Eventhough 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, eventhough 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, now U.S. Patent Application Publication No. 2014/0263541. 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, 33A and 33B , 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  2516  and the capacitor  2518 . 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, an ND  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. 68(C) , 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. 68(B) , 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. 
     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; 
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     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, now U.S. Pat. No. 8,308,040, 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.