Chapter 12. TROUBLE SHOOTING
Contents
1. Input signal does not Leakage current of external device turn OFF Drive by a limit switch with neon lamp Leakage current Fl External device Input signal does not Leakage current due to line capacity of turn OFF wiring cable AC input Leakage current Q turn OFF External device Input signal does not e Sneak current due to the use of two different power supplies E1 E2 l e E1 gt E2 Sneaked DC input e Connect an appropriate register and capacity which will make the voltage across the terminals of the input module lower than AC input e C and R values are determined by the leakage current value Reminded value C 0 1 0 47 R 47 120Q 1 2W Or make up another independent display circuit e Power supply is located on the external device side as shown below exteranl device e Connect an appropriate register which will make the voltage across input module terminal and common higher than the OFF voltage as shown below DC input Use only one power supply e Connect a sneak current prevention diode as shown below Chapter 12 TROUBLE SHOOTING 12 4 2 Output circuit troubles and corrective actions The following desires possible troubles with output circuits as well as corrective actions Condition When the output is Off excessive voltage is applied to the load The load does not turn OFF When the load is C R type timer time constant fluct2. input terminal and CPU terminal Is the indicator LED Of the input module ON Check the input signal OFF in monitor mode with the peripheral devices Is the voltage of power supply for load applied Check the wiring load of the power supply for load and restore the power Is the voltage of power ly for lied supply for load applied Check external wiring and external input equipment Output module defect Check the wiring load of the power supply for load and restore the power Contact the nearest service center REMARK 1 If the input or load signals are not switched OFF see Section 12 4 1 Chapter 12 TROUBLE SHOOTING 12 2 5 Troubleshooting flowchart used when a program cannot be written to the CPU module The following flowchart shows the corrective action procedure used when a program cannot be written to the PLC module Program cannot be written to the PC CPU Set the mode setting switch to the Is the mode setting switch remote STOP mode and execute set the remote STOP the program write Read the error code using the peripheral devices and correct the contents Is the STOP LED flickering Chapter 12 TROUBLE SHOOTING 12 3 Troubleshooting Questionnaire When problems have been met during operation of the GM6 series PLC please write down this questionnaires and contact the service center via telephone or facsimile e For errors relating to special or communica
3. Chapter 12 TROUBLE SHOOTING Chapter 12 TROUBLE SHOOTING The following explains contents diagnosis and corrective actions for various errors that can occur during system operation 12 1 Basic Procedures of Troubleshooting System reliability not only depends on reliable equipmentbut also on short down times in the event of faults The short discovery and corrective action is needed for speedy operation of system The following shows the basic instructions for troubleshooting 1 Visual checks Check the following points e Machine motion In stop and operating status e Power ON or OFF e Status of I O devices e Condition of wiring I O wires extension and communications cables e Display states of various indicators such as POWER LED RUN LED STOP LED and I O LED After checking them connect the peripheral devices and check the operation status of the PLC and the program contents 2 Trouble Check Observe any change in the error conditions during the following e Set the mode setting switch to the STOP position and then turn the power ON and OFF 3 Narrow down the possible causes of the trouble Deduce where the fault lies i e e Inside or outside of the PLC e O module or another module e PLC program 12 2 Troubleshooting This section explains the procedure for determining the cause of troubles as well as the errors and corrective actions for the error codes Occurrence of error yA Is the power LED turned OFF F
4. NNUN ER ANC ERR n and correct the STOP 04sec fault devices and then re start the system i j Correct the program so that the error elements that ee i a are nenon invoked the E_STOP function can be eliminated inthe STOP program and re start the system Cold re start Communications neng module configuration If the number of computer 4communications module is STOP 0 4 sec Snor included then adjust the maximum number with in 8 Special Communications Adjust the number of high speed communications module initialization modules loaded failure wi memory backup If the battery has no error pRUN ATC data error lfi paien has no error re set the time using the Lower battery voltage Replace the battery which the power is being applied Check the scan delay time specified by parameters and correct the parameters or the program and then re STOP 0 4 sec start the program 12 11 When power is applied When power is applie When power is appli When power is appli Q When power is appli When power is app During run When power is appli When power is appli Change into the RUN mode Change into the RUN mode Cold Change into the RUN mode When scan completes Cold p When power is applied When scan completes During execution of progran During execution of cold progran During execution of When scan completes cold During execution of i When power is app Wh
5. STOP LED is flickering The following flowchart explains corrective action procedure use when the power is applied starts or the STOP LED is flickering during operation Stop LED goes OFF Read the error code in the system flag S W error Correct the program Program error Set the operation mode to the STOP mode Correct in accordance with the error contents Write the program newly Set the operation mode to the RUN mode Program error Write down the troubleshooting questionnaires and contact the nearest Complete service center Chapter 12 TROUBLE SHOOTING 12 2 3 Troubleshooting flowchart used when the RUN and STOP LEDs turns off The following flowchart explains corrective action procedure use when the power is applied starts or the RUN and STOP LED is turned OFF is flickering during operation RUN and STOP LED is turned OFF Tum the power supply module from OFF to ON Are RUN and STOP LED Turned OFF contact the nearest service center Complete Chapter 12 TROUBLE SHOOTING 12 2 4 Troubleshooting flowchart used when the output load of the output module does not turns on The following flowchart explains corrective action procedure used when the output load of the output module does not turn ON during operation Output load does not turn ON No Is the indicator LED of the output module ON Check the output status in monitor Measure the voltage across module
6. en power is appli When power is applie When power is appli When scan complete When power is applied When scan completes
7. lowchart used when the POWER LED is tumed OFF Is the stop LED flickering Flowchart used when the STOP LED is flickering Flowchart used when the RUN and STOP LED is tumed OFF Are the RUN and STOP LED turned OFF 0 module dose not operate properly Flowchart used when the output load of the output module dose not turn on Program cannot be written Flowchart used when a program cannot be written to the PLC Chapter 12 TROUBLE SHOOTING 12 2 1 Troubleshooting flowchart used when the POWER LED turns OFF The following flowchart explains corrective action procedure used when the power is all lied or the POWER LED turns OFF during operation Power LED is turned OFF singly operatig Apply the power supply Does the Power LED turn ON See the supply power to within the rated power Does the Power LED turn ON Replace the fuse Does the Power LED turn ON Is the power supply module Fix the power supply module correctly Fixed to the base Does the Power LED turn ON 1 Eliminate the excess current 2 Switch the input power OFF then ON Is the line voltage 85 to 264VAC Is Fuse disconnected Yes Over current protection Device activated Does the Power LED turn ON Write down the troubleshooting questionnaires and contact the nearest service center Complete 12 2 Chapter 12 TROUBLE SHOOTING 12 2 2 Troubleshooting flowchart used when the
8. rror occurs STOP 0 4 sec replace the memory module Memory module Correctthe memory module program and re operate Ea program fault the system STOP 0 4 sec 2 1 2 2 0 Replace the battery if ithas error check the program 0 Program memory after cc loading it and if an error is detected replace STOP 0 4 sec backup error the CPU module 2 3 An normal program Re load the program and start it STOP 0 4 sec Module type inconsistency error the specified modules Refer to the flags _IO_TYER 10 DEER_N by parameters and the O TYER n and correct the incorrective slot and re loaded modules start the system Module mounting dismounting error Module dismounting or 31 additional mounting OEE A EOS DEER N STOP 0 4 sec and correct the in corrective slot and re start the system ection error Fuse disconnection o the flags _ FUSE_ER FUSE _ER_N during run _ER n and correct the in corrective slot and re tart the system 0 module read write error rape re Refer to the flags IO_RWER _IP_RWER_N _IO_RWER n and restart the system during run Abnormal special link Special link module interface error module data access Refer to the flags _SP_IFER IP_IFER_N IP_IFER during run n and restart the system During run Scan time 40 over than the scan delay time specified by parameters Unreadable instructions r Refer to the external device fatal error 50 ede device fatal Aags A
9. tions modules use the questionnaire included in the user s Manual of the unit 1 Telephone amp FAX No Tel FAX 2 Used Equipment 3 Details of used Equipment CPU module OS version No Serial No GMWIN version No used to compile programs 4 General description of the device or system used as the control object 5 Operations used by the CPU module Operation by the mode setting switch Operation by the GMWIN or communications 6 Is the STOP LED of the CPU module turned ON Yes No 7 GMWIN error message 8 Used initialization program initialization program 9 History of corrective actions for the error message in the article 7 10 Other tried corrective actions 11 Error character sties e Repetitive Periodic Related to a particular sequence _ Related to environment eSometimes General error assurance interval 12 Detailed Description of error contents 13 Configuration Diagram for the applied system Chapter 12 TROUBLE SHOOTING 12 4 Troubleshooting Examples Possible troubles with various circuits and their corrective actions are explained 12 4 1 Input circuit troubles and corrective actions The followings describe possible troubles with input circuits as well as corrective actions Corrective Action Input signal close not Leakage current of external device such as a drive by non contact switch a Leakage current external device
10. uates The load does not turn OFF Cause Load is half wave rectified inside in some cases itis true of a solenoid e When the polarity of the power supply is as shown in C is charged When the polarity is as shown in the voltage charged in C plus the line voltage are applied across D Max voltage is approx If a resistor is used in this way it does not pose a problem to the output element But it may make the performance of the diode D which is built in the load drop to cause problems e Leakage current by surge absorbing circuit which is connected to output element in parallel Output Leakage current e Leakage current by surge absorbing circuit which is connected to output element in parallel e Sneak current due to the use of two different power supplies Output eE1 lt E2 sneak current e E1 is switched Off and E2 is switched ON sneak current Corrective Action e Connect registers of tens to hundreds kQ across the load in parallel e Connect C and R across the load which are of registers of tens KQ When the wiring distance from the output module to the load is long there may be a leakage current due to the line capacity LR J e Drive the relay using a contact and drive the C R type timer using the since contact e Use other timer than the C R contact Some timers have half ware rectified internal circuits therefore be cautious meer ME oO e Use only one power suppl
11. y e Connect a sneak current prevention diode F igure below Output If the load is the relay etc connect a counter electromotive voltage absorbing code as show by the dot line Chapter 12 TROUBLE SHOOTING Output circuit troubles and corrective actions continued Condition The load off response time is long Output transistor is destroyed Cause e Over current at Off state The large solenoid current fluidic load L R is large such as is directly driven with the transistor output Output Off current e The off response time can be delayed by one or more second as some loads make the current flow across the diode at the off time of the transistor output Surge current of the white lamp Output IF A surge current of 10 times or more when turned ON 12 10 Corrective Action e Insert a small L R magnetic contact and drive the load using the same contact Output e To suppress the surge current make the dark current of 1 3 to 1 5 rated current flow Output Source type transistor output Chapter 12 TROUBLE SHOOTING 12 5 Error code list STOP Error LED Cause Corrective Action code Flickerin ycle gc Contact the service center if it reactively occurs when OS ROW eror a ATC rau D Q 6 Program memory faut Data memory aul Watch dog error due to J Check and correct the memory module mounting 21 Memory module defect condition Re apply the power and if an e
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