RUN LED Off

What does RUN-LED-OFF mean?

The RUN LED on the CPU module is not illuminated, indicating that the CPU module is not in an operational state or its 5V power supply is interrupted. This condition can be caused by insufficient power capacity, improper module mounting, or an internal CPU module failure, preventing system operation.

• External power supply to the power supply module is outside the rated range.
• Insufficient power capacity of the power supply module for the total current consumption of mounted modules (CPU, I/O, intelligent function modules).
• Improper physical mounting of the module in the base unit.
• Internal failure of the CPU module itself.

Click steps to track your progress.

1. 1

   Verify the supply voltage to the power supply module is within its specified rated range.

2. 2

   Calculate the total current consumption of all mounted modules (CPU, I/O, intelligent function modules) and ensure it does not exceed the power supply module's rated capacity.

3. 3

   Check the physical mounting state of the module in the base unit; ensure it is fully seated and securely fastened.

4. 4

   Perform a reset of the CPU module and observe if the RUN LED turns on.

5. 5

   If the RUN LED remains off after attempting the above steps, consult your local Mitsubishi Electric representative.