Abstract:
A method and associated apparatus for monitoring the trip status of the trip cycle in an electronic postage meter, comprising the steps of reading the state of a bistable member having a Home and In cycle states, setting a plurality of bits if the bistable member is Home, re-reading the state of the bistable member after a predetermined period of time has elapsed, storing a fatal error bit if the bistable member is in the Home state after the re-reading and attempting to complete the trip cycle, further re-reading the state of the bistable member after a predetermined period of time has elapsed if the re-reading of the state of the bistable member discloses that the bistable member is In cycle, resetting certain of the set bits if the further reading of the bistable member discloses that it is Home, and ending the trip cycle.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to copending application Ser. No. 447,918, filed on even date herewith in the name of EDWARD C. DUWEL, entitled, COMPLETING AN INCOMPLETE TRIP IN AN ELECTRONIC POSTAGE METER, the disclosure of which is incorporated herein by reference. This application is also related to copending application Ser. No. 447,815, filed on even date herewith in the name of DANILO BUAN, entitled STAND-ALONE ELECTRONIC MAILING MACHINE, the disclosure of which is incorporated herein by reference. 
     PROGRAM APPENDIX 
     A program listing for an electronic postage meter such as disclosed in the aforementioned related patent application in the name of DANILO BUAN is set forth as part of the specification at the end of the detailed description and before the claims. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to electronic postage meters, and more particularly to electronic postage meters of the stand-alone type such as disclosed in copending application Ser. No. 447,815, filed on even date herewith in the name of DANILO BUAN and entitled, STAND-ALONE ELECTRONIC MAILING MACHINE. 
     Known electronic postage meters like their earlier mechanical forerunners have generally included two separate units, i.e., a postage meter and a base or mailing machine to enable the postage meter to be physically taken to the Post Office periodically to recharge the meter. Such a meter is disclosed in U.S. Pat. No. 4,301,507 issued on Nov. 17, 1981 and assigned to Pitney Bowes, Inc. of Stamford, Conn. 
     With the advent of remote meter resetting systems, it is no longer necessary that the postage meter be separated into two distinct units since the necessity to take the meter to the Post Office for recharging has been eliminated. Further, it is desirable to have a self-contained electronic postage meter that includes the metering function as well as all drive mechanisms to reduce the size and weight of the meter as well as making it more economical to produce. The mechanical construction of such a meter is disclosed in detail in the aforementioned patent application entitled, STAND-ALONE ELECTRONIC MAILING MACHINE. 
     The program for use in such a stand-alone postage meter is disclosed in the accompanying Program Appendix. There are certain similarities between the program disclosed in the aforementioned U.S. Pat. No. 4,301,507 and the present program. However, there are also several unique exceptions, one of which is the routine for monitoring the status of the trip cycle through power down as will be described more fully hereinafter. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to monitor the status of the trip cycle in an electronic postage meter. 
     It is a further object of the present invention to store the status of the trip during the trip cycle in an electronic postage meter. 
     It is another object of the present invention to utilize non-volatile memory to control the trip through power down in an electronic postage meter. 
     It is a still further object of the present invention to store bits representative of the trip status during the trip cycle in an electronic postage meter. 
     Briefly, in accordance with the present invention, a method and associated apparatus is provided for monitoring the status of the trip cycle in an electronic postage meter including the steps of reading the state of the bistable member having at Home and In cycle states, setting a plurality of bits if the bistable member is Home, re-reading the state of the bistable member after a predetermined period of time has elapsed, storing a fatal error bit if the bistable member is in the Home state after the re-reading and attempting to complete the trip cycle, further re-reading the state of the bistable member after a predetermined period of time has elapsed if the re-reading of the state of the bistable member discloses that the bistable member is In cycle, resetting certain of the set bits if the further reading of the bistable member discloses that it is Home, and ending the trip cycle. 
     Other objects, aspects and advantages of the present invention will be apparent from the detailed description considered in conjunction with the preferred embodiment of the invention illustrated in the drawings, as follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of the general electronic circuit for a stand-alone electronic postage meter; 
     FIGS. 2A and 2B are a detailed block diagram of the electronic circuitry for a stand-alone electronic postage meter; 
     FIGS. 3A and 3B are a flowchart of the DOTRIP Routine illustrating the present invention; 
     FIG. 4 is a flowchart for the logic used in the DOTRIP Routine; 
     FIG. 5 is a timing diagram for the logic used in the DOTRIP Routine; 
     FIG. 6 is a plan view of the print wheel selection mechanism for a stand-alone electronic postage meter; and 
     FIG. 7 is a side elevation of the locking mechanism for the print wheel selection mechanism. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, the electronic postage meter includes an 8-bit microprocessor 10 (CPU), such as an Intel Model 8085A microprocessor which is connected to various components through a system bus 12. ROM 14 is connected to the microprocessor 10 through the system bus 12. The ROM 14 stores the programs for controlling the postage meter. It should be understood that the term ROM as used herein includes permanently programmed and reprogrammable devices. An integrated circuit 16, which may be Intel Model 8155, is connected to the system bus 12 and includes RAM, input and output lines and a timer. The RAM portion of the intergrated circuit 16 has memory space allocated for transient storage of the data for the ascending register and descending register. An external data communication port 18 is connected to the microprocessor 10 through optical isolator 20. The external data communication port 18 allows connection with devices such as an electronic scale, an external computer, servicing equipment and the like. Also electrically connected to the microprocessor 10 through the system bus 12 is the keyboard 22 of the postage meter and a non-volatile memory (NVM) 24. Stepper motors 26, 28 are also in electrical connection with the microprocessor 10 via motor drivers 30 and the integrated circuit 16. A reset and power control 32 is electrically connected between the integrated circuit 16, the NVM 24 and the microprocessor 10. A relay 34 connects the AC printer motor 36 to the integrated circuit 16. A display 38 is also electrically connected to the integrated circuit 16. Trip photosensor 40 is connected to the microprocessor 10 through integrated circuit 16 to indicate the presence of an envelope to be stamped, as described more fully in the aforementioned patent application entitled, STAND-ALONE ELECTRONIC MAILING MACHINE. 
     The electronic postage meter is controlled by the microprocessor 10 operating under control of the programs stored in the ROM 14. The microprocessor 10 accepts information entered via the keyboard 22 or via the external communication port 18 from external message generators. Critical accounting data and other important information is stored in the non-volatile memory 24. The non-volatile memory 24 may be an MNOS semiconductor type memory, a battery augmented CMOS memory, core memory, or other suitable non-volatile memory component. The non-volatile memory 24 stores critical postage meter data during periods when power is not applied to the postage meter. This data includes, in addition to the serial number of the mailing machine or postage meter, information as to the value in the descending register (the amount of postage available for printing), the value in the ascending register (the total amount of postage printed by the meter), and the value in the piece count register (the total number of cycles the meter has performed), as well as other types of data, such as trip status, initialization and service information, which are desired to be retained in the memory even though no power is applied to the meter. 
     When an on/off power switch 42 is turned on (closed) a power supply internal to the mailing machine energizes the microprocessor 10 and the balance of the electronic components. The information stored in the non-volatile memory 24 is transferred via the microprocesor 10 to the RAM of the integrated circuit 16. After power up the RAM contains an image or copy of the information stored in the non-volatile memory 24 prior to energization. During operation of the postage meter, certain of the data in the RAM is modified. Accordingly, when postage is printed, the descending register will be reduced by the value of the printed postage, the ascending register increased by the value of the printed postage and the piece counter register incremented. When the power switch 42 is turned off (opened), the updated data in the RAM is transferred via the microprocessor 10 back into a suitably prepared area of the non-volatile memory 24. A like transfer of information between the non-volatile memory 24 and the RAM takes place during power failure. 
     Referring to FIGS. 2A and 2B, a more detailed block diagram of the arrangement of the electrical components for the postage meter is illustrated generally as 48. Power is supplied to the postage meter from the AC line voltage, typically 115 volts. This line voltage is applied to the meter through a hot switch 50 which cuts off power to the postage meter to protect the electrical components thereof if the temperature rises above a preset limit, nominally 70° C. The hot switch 50 is connected to the AC drive motor 36A through an RF filter 52 and an opto-triac 54 which provides isolation between the line voltage and the control logic for the meter. The hot switch 50 is also connected to a transformer 56 protected by a fuse 58. The output of the transformer 56 is coupled to a pre-regulator 59 through a cold switch 60. The cold switch 60 cuts off power to the pre-regulator 59 if the temperature drops below a preset limit, nominally 0° C. The pre-regulator 59 provides an output voltage of a predetermined range to a switcher 62 which generates the output voltage + 5 V; and the voltages for generating -12 V and -30 V. 
     The +5 V is applied to a +3 volt regulator 64 and then to the display 38A. The +5 V from the switcher 62 is also applied to a +5 V filter 66 which provides +5 V for logic circuits. Specifically, the +5 V is applied to the keyboard 22A, the display 38A, and bank, digit and trip sensor logic 68 and to the integrated circuits. The -12 V is applied to a -12 V regulator 70 and then to the non-volatile memory 24A. 
     The -30 V output from the switcher 62 is also applied to a -30 V regulator 74 and then to a -30 V switch 76 which switches its output voltage on and off in response to the requirements of writing in NVM as dictated by the program. The output of the -30 V switch is applied to the non-volatile memory 24A. The -30 V supply is connected to the power on reset 72 of the microprocessor 10A. 
     +5 V from the switcher 62 is also supplied to one input of he power on reset 72; the other input receives -30 V from the regulator 74 as previously described. A low voltage sensor 88 also receives one input of +5 V from the switcher 62 and its other input from the pre-regulator 59; its output is applied to the microprocessor 10A. The low voltage sensor 88 detects power failure and communicates this to the microprocessor 10A which in turn addresses the RAM through system bus 12A to transfer all security data present in the RAM to the non-volatile memory 24A. 
     Another output from the pre-regulator 59 in the form of +24 V is applied to the digit and bank motor drive 30A for the bank motor 26A and digit motor 28A, which selects the particular printing wheel (bank) which is to be activated and the particular digit of the selected printing wheel which is to be set. 
     An output strobe from the integrated circuit 16A is buffered through buffer driver 68 and applied to digit sensor (encoder) 78, bank sensor (encoder) 80, and trip sensor 40A. The opto strobe applies power to the digit sensor 78, bank sensor 80 and trip sensor 40A when needed. The output from the trip sensor 40A is applied to the input/output lines 82 which are coupled to the intergrated circuit 16A. The outputs from the digit sensor 78 and bank sensor 80 and cycle switch 84 are applied to a storage buffer 86. 
     During power up, the key switch 42, see FIG. 1, is closed, and the AC line voltage energizes the electrical components previously described and an Initialization process will occur. Such initialization may include a hard and/or soft initialization process as disclosed in the aforementioned U.S. Pat. No. 4,301,507. Preferably the Initialization process is that described in copending application Ser. No. 447,913, filed on even date herewith in the names of Alton B. Eckert and Easwaran C. N. Nambudiri entitled, INITIALIZING THE PRINT WHEELS IN AN ELECTRONIC POSTAGE METER, and assigned to the same assignee as the present invention. 
     In operation, the microprocessor 10A under control of the ROM 14A and possibly the auxiliary ROM 100 communicates over the address bus 94 and control bus 96 with the device select 98. The output of the device select 98 communicates with the particular module to be addressed over select lines 99. The modules to be addressed are the RAM, the ROM 14A, an auxiliary ROM 100, a demultiplexer 102, NVM logic 104 and the buffer 86. The RAM of integrated circuit 16A provides the working memory for the postage meter and the microprocessor 10A. The ROM 14A stores the program; the auxiliary ROM 100 may be used to provide additional program storage space. The non-volatile memory 24A provides storage of all security information for the meter and retains such information during power down or power failure. The demultiplexer 102 latches the lower eight (8) bits of address information that defines a particular location which is used immediately thereafter. The NVM logic 104 controls the mode of operation of the NVM 24A and also provides ready wait and NVM ready signals to the microprocessor 10A to indicate the presence of the slow speed device (NVM) as active on the bus 12A. 
     As previously mentioned, the digital sensor 78 (optical encoder) and bank sensor 80, (optical encoder) and cycle switch 84 whose current state is read, i.e., &#34;Home&#34; or &#34;In Cycle&#34;, apply input signals to the buffer 86 which sends output signals over data bus 108 to the microprocessor 10A for storage in the proper RAM location. 
     The RAM is also electrically coupled to I/O lines to transmit or receive data from the trip sensor 40A, the display 38A, keyboard 22A, and privilege access switch 110, if present. The privilege access switch 110 may be used in applications which require manual resetting of meter postage via a switch which is kept under seal. 
     A program listing for an electronic postage meter of the type described in the aforementioned patent application entitled, STAND-ALONE ELECTRONIC MAILING MACHINE is set forth in the accompanying Program Appendix. This program is similar in certain respects to the program disclosed in the aforementioned United States Letters Patent. However, there are significant differences in certain of the routines of the present program which interact with the electrical and mechanical components of the electronic postage meter disclosed in the aforementioned patent application entitled, STAND-ALONE ELECTRONIC MAILING MACHINE. Specifically, one such exception occurs during the trip routine in that the trip cycle is monitored as illustrated in FIGS. 3A and 3B. After the postage meter is properly initialized during power up and the desired postage values are set via the keyboard 22A, the postage meter is ready for the trip cycle or the printing of postage on an envelope. (See the aforementioned patent application entitled, INITIALIZING THE PRINT WHEELS IN AN ELECTRONIC POSTAGE METER). To accomplish this operation, an envelope is inserted in the throat of the postage meter. The end of the envelope is sensed by the trip sensor 40A which sends a signal to the RAM which communicates with the microprocessor 10A under control of the program in the ROM 14A to begin the trip cycle, illustrated as DOTRIP Routine 120 in FIG. 3. Additionally, the meter may be tripped by an external trip as disclosed in copending application Ser. No. 447,925, filed on even date herewith in the names of John H. Sodenberg and Edward C. Duwel entitled, CONTROLLING FIRMWARE BRANCH POINTS IN AN ELECTRONIC POSTAGE METER. 
     When DOTRIP Routine 120 commences, the display 38A is blanked and the timer which provides a blinking display is deactivated. The position of the cycle switch 84 is then read by reading its current state. This current state is then stored in the storage buffer 86 and eventually communicated to the RAM. If the cycle switch is in its &#34;Home&#34; or &#34;off&#34; position, the routine proceeds. However, if the cycle switch is In Cyle (current flowing) FINTR2 sequence occurs and a fatal error is declared and logged by setting a bit in non-volatile memory 24A. The meter is then locked up and rendered non-functional. 
     If the cycle switch 84 is Home (not in cycle), certain flags or bits are then set. Specifically, the following bits are set: 
     1. UNKSEL--not certain where the trip mechanism is or if in a postage selection--this is set TRUE. If not set TRUE, i.e., FALSE, nothing mechanically is being done. 
     2. QUEREG--end of a trip cycle to output extra information--this is set TRUE for a trip and false for no trip. 
     3. TRPREQ--request has been made for a trip--set FALSE when we start the trip. 
     4. QUEPOS--at the end of the trip cycle this will result in a postage value message--this is set TRUE. After the trip is completed it is set FALSE. 
     The UNKSEL and QUEREG bits are transmitted from the RAM 16A to the non-volatile memory 24A. The trip lever 142 of the selection mechanism is then moved under control of the microprocessor 10A from its lock position to its trip position, see FIG. 6. A sensor sends a flag to the microprocessor 10A to indicate whether this movement was accomplished. If it is not accomplished, a fatal error is declared and logged by setting a bit in the non-volatile memory 24A. The meter is then locked up and rendered inoperative. 
     If the move is okay the AC drive motor is energized and the power down interrupt is disabled so that the postage can be accounted for by undergoing a DOACCT Subroutine similar to that disclosed in the aforementioned U.S. Pat. No. 4,301,507. 
     In the DOACCT Subroutine, the value of the ascending register in the RAM is increased to the value present in the ascending register plus the preset postage value which was just used in printing postage on an envelope. Thereafter a new cycle redundancy character (CRC) is computed for the ascending register. The descending register in the RAM is then reduced to the present value in the descending register minus the preset postage value which was just used in printing postage on an envelope. Likewise, a new cyclic redundancy character is computed for the descending register. The value of the piece count register in the RAM is then incremented to the value present in the price count register plus one (1) to account for the piece of mail just stamped with preset postage. The DOACCT Subroutine is then completed and its completion is reported to the superordinate process, e.g., the DOTRIP. After completion of the accounding Subroutine DOACCT, another flat or bit is set INCYC=TRUE. If INCYC=FALSE, the DOTRIP routine has not progressed far enough to complete the accounting. This INCYC bit is transmitted from the ram to the non-volatile memory 24A. 
     After setting INCYC=TRUE, the power down interrupt is then enabled once again. A period is then entered where the cycle switch must change from &#34;Home&#34; indication to &#34;In-Cycle&#34; indication before the elapse of a predetermined period of time, e.g., 20 milliseconds. If this time period expires and the cycle switch still yields a &#34;Home&#34; indication, a fatal error is declared and stored in non-volatile memory 24A and the remainder of the trip is attempted to be completed by procedure FINTRP as disclosed in the aforementioned related copending patent application entitled, COMPLETING AN INCOMPLETE TRIP IN AN ELECTRONIC POSTAGE METER. 
     Once the cycle switch 84 yields the desired &#34;In-Cycle&#34; condition, the trip selection mechanism is moved from the trip position back to its lock position. If this move is unsuccessful, the error condition is stored in non-volatile memory and the remainder of the trip completed as normal. 
     The last portion of the trip cycle is waiting for the cycle switch to change from &#34;In-Cycle&#34; back to &#34;Home&#34; condition. This transition has a time limit, e.g., of one (1) second, and if exceeded will result in a fatal error being declared and stored in non-volatile memory 24A. Once the cycle switch again indicates a &#34;Home&#34; condition, the UNKSEL bit is set FALSE and the INCYC bit set FALSE. Both the INCYC bit and the UNKSEL bit are stored in non-volatile memory 24A for the purpose of being tolerant of power interruptions during the trip process. Thereafter, the AC drive motor 36A is de-energized and the ENABLED bit is set FALSE completing the DOTRIP Routine. The fact of completion is reported to the superordinate process, e.g., the executive. 
     Referring to FIG. 4, a flow chart for the logic is set forth as 130, designated PWRABN which occurs during the power up cycle. If the UNKSEL bit is FALSE, control is resumed by the superordinate process since no trip or postage selection is in progress. However, if UNKSEL bit is TRUE, the QUEREG bit is TRUE and the INCYC bit is TRUE the FINTRP Routine as disclosed in the aforementioned copending patent application entitled, COMPLETING AN INCOMPLETE TRIP IN AN ELECTRONIC POSTAGE METER, is commenced. Upon completion of the FINTRP Routine the UNKSEL bit is examined, and if determined to be TRUE, control is resumed by superordinate process. If UNKSEL is FALSE a SEKP08 Routine is undertaken to establish a predefined reference for the entire selection mechanism. If the INCYC bit is FALSE, SEKTRP and DOACCT Routines are undergone prior to the FINTRP Routine. The DOACCT Subroutine has been previously discussed. The SEKTRP Subroutine moves the trip selection mechanism from its current position to the trip position. 
     Referring to FIG. 5, the timing diagram for the bits and cycle switch referred to in FIGS. 3 and 4 is illustrated generally as 132. As seen by the arrow indicating the start of the trip cycle, the trip cycle commences with the TRPREQ bit changing from TRUE to FALSE and the QUEREG and UNKSEL bits changing from FALSE to TRUE. Sometime subsequent to the start of the trip cycle the CYCSW bit (cycle switch) goes TRUE (positive) since it is in cycle. Either shortly before or shortly after the CYCSW bit goes TRUE the INCYC bit is set TRUE. At the end of the trip as indicated in FIG. 5, the UNKSEL, INCYC and CYCSW bits change from TRUE to FALSE. Subsequently, to allow for certain administrative actions to take place in the meter, the QUEREG bit goes FALSE and the trip is complete. Thereafter, TRPREQ may be set TRUE in preparation for another trip. The commitment to start a trip begins when the TRPREQ bit changes from TRUE to FALSE. 
     Referring to FIGS. 6 and 7, the trip selection mechanism for an electronic postage meter of the type disclosed in the aforementioned copending patent application entitled, STAND-ALONE ELECTRONIC MAILING MACHINE, is illustrated generally as 140 and 180, respectively. Further details regarding the trip selection mechanism and the other mechanical components of such an electronic postage meter may be obtained from said aforementioned patent application, the disclosure of which is incorporated by reference as previously noted. The trip selection mechanism 140 includes a trip lever 142 affixed to a rotatable trip shaft 144 adjacent to one end thereof for engagement and disengagement with a clutch 145. The trip shaft 144 also includes a gear 146 affixed thereto for engagement with and rotation by a gear 148 affixed to a tri-lobed shaft 150. A stepper motor 28A includes an output shaft 152 having a gear 154 and an optical encoder disk 156 (not to scale) on the output shaft 152. The optical encoder disk 156 is received within a sensor 158 so that the position of the stepper motor shaft 152 can be determined. The gear 154 engages a gear 157 affixed to the tri-lobed shaft 150. The gear 148 is disposed within an opening of a carriage 160. 
     In operation, as seen in FIGS. 6 and 7, the stepper motor 28A is energized to rotate the stepper motor gear 154 and the gear 157 affixed to the tri-lobed shaft 150. Rotation of the tri-lobed shaft 150 rotates gear 146 affixed to the trip shaft 144 which rotates a locking lever 162 affixed to the trip lever shaft 144 out of engagement with a carriage slot 164, thereby freeing the carriage 160 for movement along the tri-lobed shaft 150. As shown in FIGS. 6 and 7, the trip shaft 144 and trip lever 142 are in their home or middle position. The down position of the trip lever 142 is the set position. The up position of the trip lever 142 is the trip position. In the middle or intermediate position of the trip lever 142, as shown in FIG. 6., a locked position exists. Rotation of the trip lever 142 to the set position disengages the locking lever 162 from the carriage slot 164 and allows movement to be imparted to the carriage 160 in either direction along the tri-lobed shaft 150 for selecting the appropriate bank of the print wheels (not shown) in response to energization of bank stepper motor 26A which moves gear 166 via stepper motor gear 168. The individual digit of the desired print wheel is then selected by the stepper motor 28A which rotates the tri-lobed shaft 150 and thus gear 148 which is engageable with the teeth of a selected one of four print wheel racks 170. 
     From the foregoing description it is apparent that the bistable member, i.e., the cycle switch, provides the only system feedback for the DOTRIP Routine in monitoring the status of the trip cycle. When the cycle switch is engaging a clutch (trip lever unlocked), the cycle switch is in cycle. When the cycle switch is not engaging the clutch (trip lever locked), the cycle switch is Home. 
     It is known and understood for the purpose of the present application that the term postage meter refers to the general class of device for the imprinting of a defined unit value for governmental or private carrier delivery of parcels, envelopes or other like application for unit value printing. Thus, although the term postage meter is utilized, it is both known and employed in the trade as a general term for devices utilizied in conjunction with services other than those exclusively employed by governmental postage and tax services. For example, private, parcel and freight services purchase and employ such meters as a means to provide unit value printing and accounting for individual parcels. 
     It should be understood by those skilled in the art that various modifications may be made in the present invention without departing from the spirit and scope thereof as described in the foregoing description and defined in the appended claims. ##SPC1## ##SPC2## ##SPC3## ##SPC4## ##SPC5## ##SPC6## ##SPC7## ##SPC8## ##SPC9## ##SPC10## ##SPC11## ##SPC12## ##SPC13## ##SPC14## ##SPC15## ##SPC16## ##SPC17## ##SPC18## ##SPC19## ##SPC20## ##SPC21## ##SPC22## ##SPC23## ##SPC24## ##SPC25## ##SPC26## ##SPC27## ##SPC28## ##SPC29## ##SPC30##