Chapter9 Troubleshooting; Troubleshooting Basics - Mitsubishi Electric MELSEC QS SERIES User Manual

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TROUBLESHOOTING

CHAPTER9 TROUBLESHOOTING

This section describes the various types of trouble that occur when the the safety remote
I/O module is operated, and causes and remedies of these troubles.

9.1 Troubleshooting Basics

In order to increase the reliability of the system, not only highly reliable devices are used
but also the speedy startup of the system after the occurrence of trouble becomes an
important factor.
To start up the system speedily, the cause of the trouble must be located and eliminated
correctly. The basic three points that must be followed in the troubleshooting are as
follows.
(1) Visual inspection
(2) Checking malfunctions
(3) Narrowing down the range of trouble occurrence causes
Visually check the following.
1) Movement of programmable controller (stop status and operation status)
2) Power supply status of the safety remote I/O module
3) Status of extenal devices
4) Installation condition of the safety power supply module, safety CPU module
and safety master module
5) Status of wiring (I/O wires, power cables, CC-Link dedcated cables)
6) Display status of various types of indicators ("POWER" LED, "RUN" LED,
"ERR." LED, etc.)
7) Status of setting of various types of set switches
After checking items 1) to 7), connect GX Developer to the safety CPU module,
and conduct PLC diagnostics or monitor the operating condition and program
contents of the safety CPU module.
Check how the malfunction of the programmable controller changes when the
following operations are performed.
1) Set the RUN/STOP/RESET switch of the safety CPU module to "STOP".
2) Perform the reset operation with the RUN/STOP/RESET switch of the safety
CPU module.
3) Turn ON and OFF the power supply of the safety remote I/O module.
4) Perform the reset operation with the reset switch of the safety remote I/O
module.
Estimate the failure location in accordance with items (1) and (2) above.
1) Safety remote I/O module or external devices
2) Safety master module or others
3) Safety CPU module
4) Sequence program
9.1 Troubleshooting Basics
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