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Profibus Problem at MCC

Profibus Problem at MCC

Profibus Problem at MCC

Dear All,
We have connected our whole MCC panel with profibus including constant speed and variable speed motors. Today I have found that about 20 motors were giving communication problem. When these were reset they became ok. But this kind of problem frequently occurs with 2 or 3 motors giving communication problem

RE: Profibus Problem at MCC

The #1 cause of that is people making up their own Profibus cables, thinking it's no big deal. It is.

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RE: Profibus Problem at MCC

Does the communication problems only happen when the VFD's run?
If yes, then it is probably a cabling issue as jraef indicates. VFD's, as well as varying the frequency, are a good method of finding poor installation techniques and inferior cables. The problem is not the VFD btw.
If comms problems are there all the time, it could be the type of connectors/cables used but could be something deeper.

RE: Profibus Problem at MCC

From the information you provide it could really be a number of problems.
The specifications for the physical layer of a Profibus network are very strict, and if any of the requirements is not followed it could lead to problems.

To start you may want to make sure all components (including cables and connectors) are Profibus certified.
If they are make sure the physical dimensions of your network are within spec. Not only the total bus length is specified, also the MINIMUM length between two slaves is specified. Next step is to make sure all your bus parameters are OK.
You can check IEC 61158, or contact the experts (like procentec - see djs' post above) for more information.

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