Troubleshooting Of The Master Module - Mitsubishi Electric MELSEC-Q Series User Manual

10.6

Troubleshooting of the Master Module

This section describes the troubleshooting of the master module.
(1) When the RUN LED does not turn on even when the power supply is turned on.
Check the installation or connection of the master module.
Check the internal current consumption of the entire system.
Check for a programmable controller error using the
programming tool.
(2) When the LINK LED on the master module does not flash
Check for a programmable controller error using the
programming tool.
(3) When the ALM LED on the master module is flashing at 0.2 second intervals
Check the power supply voltage of the 24VDC external
power supply.
Check that the power cables (24V, 0V) are not short-
circuited.
Check the wiring of the terminal blocks.
98
Check item
Check item
Check item
Action
Remove the master module. Then mount or connect it again.
Examine the system configuration so that the internal current
consumption does not exceed the rated output current of the
power supply module.
For how to calculate the current consumption of the system,
refer to the following.
 User's Manual (Hardware Design, Maintenance and
Inspection) for the CPU module used
 MELSEC-L CC-Link IE Field Network Head Module
User's Manual
Check and correct the error using the PLC diagnostics of the
programming tool.
Action
Check and correct the error using the PLC diagnostics of the
programming tool.
Action
Adjust the power supply voltage of the 24VDC external
power supply within the rated value (21.6VDC to 27.6VDC).
(The recommended voltage is 26.4VDC.)
• Check that the power cables (24V, 0V) are not
disconnected or short-circuited.
• When crimping the link connector, check that the pin layout
is correct.
• Check that the 24VDC external power supply is properly
connected to the terminal blocks of the master module and
the slave module.
• Check that there is no short circuit or incorrect wiring and
screws are tightened sufficiently.