Troubleshooting; Fundamentals Of Troubleshooting - Mitsubishi Electric MELCEC Q Series User Manual

11. TROUBLESHOOTING

11 TROUBLESHOOTING
The description, cause investigation, and corrective actions of each error which may occur
during system usage are described.

11.1 Fundamentals of Troubleshooting

Besides using obviously highly-reliable devices to increase system reliability, it is an
important point to quickly start up the system again when an error occurs.
In order to quickly start up the system, find the cause of the problem and resolve it. There
are the following three basic points to be aware of when performing troubleshooting.
(1)
(2)
(3)
Visual confirmation
Confirm the following points:
(a) Machine operation (stop status and operation status)
(b) Power supply ON/OFF
(c) I/O equipment status
(d) Wiring status (I/O wires and cable)
(e) Display status of each display indicator (POWER LED, RUN LED, ERR. LED, I/
O LED, etc.)
(f) Status of each setting switch (extension base, latch, etc.)
After confirming (a) to (f), connect a peripheral device and observe the operation
status of the programmable controller and program contents.
Error confirmation
Observe how the error changes by performing the following operations:
(a) Set the RUN/STOP switch to "STOP".
(b) Reset using the RUN/STOP switch.
(c) Turn on and off the power supply.
Narrow down the range.
By performing the (1) and (2) above, assume the faulty area in the following:
(a) Programmable controller or external devices?
(b) I/O module or others?
(c) Sequence program?
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