Mitsubishi MELSEC LJ71C24, User Manual

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A - 14 A - 14
13.3.2 Checking with the buffer memory................................................................................................ 13-15
14 MAINTENANCE AND INSPECTION
14.1 Inspection Items.................................................................................................................................. 14- 1
14.2 When Replacing Modules................................................................................................................... 14- 2
14.2.1 Procedure of C24 replacement and re-registration of data ........................................................ 14- 2
15 TROUBLESHOOTING
15.1 Checking the Status of the C24.......................................................................................................... 15- 1
15.1.1 Checking the H/W LED information............................................................................................. 15- 2
15.1.2 Checking the H/W switch information.......................................................................................... 15- 6
15.1.3 Reading the RS-232 control signal status................................................................................... 15- 9
15.1.4 Reading the data communication status (Transmission sequence status) ............................... 15-10
15.1.5 Reading the switch setting status ................................................................................................ 15-11
15.1.6 How to read the current operation status .................................................................................... 15-13
15.2 Error Code........................................................................................................................................... 15-15
15.2.1 How to check the error codes...................................................................................................... 15-15
15.2.2 Error code list ............................................................................................................................... 15-19
15.2.3 A compatible 1C frame communications error code list ............................................................. 15-31
15.2.4 Error code list while modem function is used.............................................................................. 15-32
15.3 Troubleshooting by Symptom............................................................................................................. 15-34
15.3.1 The "RUN" LED is turned OFF .................................................................................................... 15-36
15.3.2 The "RD" LED does not blink even after message transmission from the external device....... 15-37
15.3.3 No response message is returned even though the external device transmitted a message
and the "RD" LED blinked............................................................................................................ 15-38
15.3.4 Transmission request does not make the "SD" LED blink ......................................................... 15-39
15.3.5 Read request signal does not turn ON even though the external device transmitted
a message and the "RD" LED was blinking ................................................................................ 15-40
15.3.6 The CPRTCL instruction execution is not completed although the "RD" LED blinked.............. 15-41
15.3.7 Communication error "NAK" ........................................................................................................ 15-42
15.3.8 Communication error "C/N" ......................................................................................................... 15-42
15.3.9 Communication error "P/S".......................................................................................................... 15-43
15.3.10 Communication error "PRO."..................................................................................................... 15-44
15.3.11 Communication error "SIO" ....................................................................................................... 15-45
15.3.12 Communication error "CH1 ERR." or "CH2 ERR." ................................................................... 15-46
15.3.13 Communication is intermittent ................................................................................................... 15-48
15.3.14 Undecodable data are transmitted or received......................................................................... 15-50
15.3.15 Whether the communication error is caused on the C24 or external device is unclear .......... 15-51
15.3.16 Communication is not available via the modem ....................................................................... 15-52
15.3.17 Communication is not available with the ISDN sub-address.................................................... 15-52
15.3.18 Constant cycle transmission is not performed normally ........................................................... 15-53
15.3.19 Condition agreement transmission is not performed normally................................................. 15-53
15.3.20 Data cannot be received due to by an interrupt program ......................................................... 15-53
15.3.21 Data cannot be written to the flash ROM .................................................................................. 15-53
15.3.22 Troubleshooting on the protocol setting data reading/writing................................................... 15-54
15.3.23 The "ERR." LED is lit ................................................................................................................. 15-54
15.4 Initializing Error Information of the Serial Communication Module ................................................... 15-55
15.5 Clearing the Programmable Controller CPU Information .................................................................. 15-59