Chapter18 Troubleshooting; Troubleshooting Basics - Mitsubishi MELSEC-Q Series User Manual

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TROUBLESHOOTING

CHAPTER18 TROUBLESHOOTING

This chapter explains various types of error information, the return values (error codes) of
the bus interface functions and MELSEC data link functions, and the corrective actions for
the cases of problem occurrence.

18.1 Troubleshooting Basics

First check the following three points for troubleshooting.
(1) Visual checks
(2) Fault verification
(3) Narrowing down the range
Check the following.
1) Check the operating states of the external devices
2) Check the operating state of the external power supply
3) Check if the cables are connected normally.
4) Check the LEDs to see the operating states of the C Controller module and
power supply module.
Example: The RUN and ERR. LEDs of the C Controller module
The POWER LED of the power supply module
5) Check if the LEDs of the input and output modules can turn on responding to
the input (X) and output (Y) states.
6) Check if each module is securely mounted to the base unit.
After checking 1) to 6), connect the C Controller to external devices and check the
user program operation.
Check how the fault state changes by the following operations.
1) Switch the input (X) status between ON and OFF and check if the status can
be read with a test program.
2) Switch the output (Y) status between ON and OFF and check if the status of
the corresponding external device changes correctly.
By the above (1) and (2), hardware or software that showed many error results can be
identified as a cause of the error.
Narrow the range from the following to identify the hardware or software that could be
the error cause, and troubleshoot the problem.
1) C Controller module
2) External device
3) Module (other than the C Controller module)
4) Connection cable
5) User program
18.1 Troubleshooting Basics
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