11 TROUBLESHOOTING

11.2.10 Flowchart for when the "BOOT" LED is flickering

MELSEC-Q

The following shows the flowchart to be followed when the "BOOT" LED of the CPU module flickers at PLC power-on, at operation start or during operation.

"BOOT" LED flickering

Power off the PLC.

Remove the memory card.

Move the DIP switches SW2 and

SW3 of the CPU module to ON.

Power on the PLC.

 

Is the "BOOT" LED turned on?

YES

 

Completion of automatic write from

 

 

 

 

 

 

 

 

 

 

memory card to standard ROM

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Perform boot operation from

 

 

 

 

 

 

 

 

 

 

CPU module hardware fault.

 

 

 

 

standard ROM.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Please consult your local Mitsubishi

 

 

 

 

 

 

 

 

 

service center or representative,

 

 

 

 

 

 

 

 

 

explaining a detailed description

 

 

 

 

 

 

 

 

 

of the problem.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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11 - 9