When The Power Led Does Not Turn On; When The Mode Led Does Not Turn On - Mitsubishi MELSEC L Series User Manual

15.1.1

When the POWER LED does not turn on

Check the following:
The MODE LED of the CPU module is on.
Power supply voltage is not appropriate.
The internal current consumption for the entire system
exceeds the rated output current of the power supply
module.
The POWER LED turns on when power is supplied again to
the system after all modules, except for the power supply
module, were removed.
If the POWER LED does not turn on even after taking the above actions, the possible cause is a hardware failure.
Please consult your local Mitsubishi service center or representative, explaining a detailed description of the problem.
15.1.2

When the MODE LED does not turn on

Check the following:
The forced ON/OFF is set.
The MODE LED turns on when power is supplied to the
system again after the power supply module was replaced.
AC power is not supplied to the power supply module.
The MODE LED does not turn on even when power is
supplied to the system again after the power supply module
was replaced.
A branch module is connected to another branch module
using an extension cable.
If the MODE LED does not turn on even after taking the above actions, the possible cause is a hardware failure.
Please consult your local Mitsubishi service center or representative, explaining a detailed description of the problem.
92
Check item
Check item
Action
The power supply module has failed. Replace the power
supply module.
Supply power voltage within the specified range.
( Page 67, Section 7.2)
Reexamine the system configuration so that the internal
current consumption does not exceed the rated output
current.
( Page 401, Appendix 9)
Repeatedly supply power to the system, returning the
modules back to the system one by one.
The last module mounted immediately before the POWER
LED turned off is failed.
Action
Cancel the forced ON/OFF registration.
The original power supply module has a problem.
Please consult your local Mitsubishi service center or
representative, explaining a detailed description of the
problem.
Supply AC power to the power supply module.
The CPU module or any other module mounted has a
problem.
Repeatedly supply power to the system, returning the
modules back to the system one by one.
The last module mounted immediately before the MODE
LED turned off is failed.
Connection of the extension cable is incorrect. Connect the
cable correctly.