Hello Everyone,

We are facing communication loss problem between PLC-S7-400H and RIO Panel. This RIO Panel having two ET200M Rack communicating with PLC on profibus. IM 153-2 Redundancy bundle is used in ET200M Rack. Profibus OLM is used in RIO panel to convert fiber optic to Profibus. one ET200M (profibus address 7) is communicating with PLC without any problem. Another ET200M (Profibus address 6) having frequent communication loss problem with PLC.

Once communication loss between profibus node 6 and PLC, after few seconds same node  automatically communicates again with PLC. This communication loss happen frequently in night time only. In day time only 2 to 3 times happen.

Please find attached screen shots for CPU diagnostic buffer and Profibus Network diagram.

Please advice on this.

Thank you

hi sacheen,

is there anything at night what can disturb the communication?

check the wiring and proper grounding of the nodes.

regards,

Hello..,

Thanks for your reply,

I will check proper grounding of profibus nodes.

Also I will check the devices or Power Cables which is creating noise at night time.

Thank you

Regards

Sacheen

Hello,

I replaced the backplane modules for IM-153-2 and DI Cards, after that problem of communication break is solved.

Thank you your support

Regards

Sacheen