11 TROUBLESHOOTING

11.2.17 Flowchart for when CONTROL BUS ERR. occurs

MELSEC-Q

The following shows the flowchart to be followed when CONTROL BUS ERR. occurs at PLC power-on or during operation.

This flow chart can be confirmed only when a specific slot/base unit can be detected by the error code.

CONTROL BUS ERR. occurs.

Check the slot base unit where error occurred with the GX Developer.

Is the module of the

NO

 

 

 

 

 

 

applicable slot installed properly?

 

 

 

 

 

 

 

 

 

 

Is the extension cable of the

 

 

 

Install the module and cable properly.

 

 

 

 

 

 

 

applicable base unit

 

 

 

 

 

 

 

 

installed properly?

 

 

 

 

 

 

 

 

 

YES

 

NO

Is the "ERR." LED

YES

 

 

 

 

 

 

 

 

turned off?

 

 

 

 

 

 

 

 

 

 

 

 

Are all the extension

NO

 

 

 

 

 

 

 

cables of the base unit

 

 

Install the extension cable properly.

 

 

connected properly?

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

Is the "ERR." LED

YES

 

 

 

 

 

 

 

 

 

turned off?

 

 

 

 

Proper operation

 

 

 

 

 

 

 

 

Replace the applicable module.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Error detection

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Proper operation

Replace the CPU module.

Error detection

Replace the applicable

Proper operation

base unit.

 

Error detection

Hardware fault

Please consult your local Mitsubishi service center or representative, explaining a detailed description

 

of the problem.

Completion

 

 

11 - 17

 

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