User`s manual

Troubleshooting Troubleshooting

MELSEC System Q, Hardware 11 – 21

11.2.21 When "CONTROL BUS ERR." has occurred

* May be the failure could be caused by electromagnetic noise. Refer to the notes concerning the wiring in section

9.6.

The CONTROL BUS ERR. has occured.

Check the slot where error occurred

with the programming device.

YES

Is the module of the

applicable slot mounted properly?

Is the extension cable of the applicable

base unit connected

properly?

Mount the module and extension cable properly.

YES

Are all the extension

cables of the base unit connected

properly?

Connect the extension cables properly.

YES

Replace the corresponding

module.

Normal operation

Completed

Replace the CPU module.

Replace the applicable base unit.

Error detection

Hardware fault.

Please consult your local Mitsubishi

service center or representative.

Error detection*

Is the ERR. LED of the CPU on?