Akif KC

Bus Off Detected Problem

6 posts in this topic

Hi All,

I came across a new problem called Bus Off Error Detected in my one of the Devicenet Cards here in plant. I went through different web searches regarding that and came to know there are different problems that will cause this. I cam to know  temporary fix which will help to resume the production which is unplug the devicenet and plug it in. But this problem is now happening frequently and it is giving headache for the operator. Can someone please tell me more detailed solution for this ? Thank you very much.

Akif.

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Something has changed to your DeviceNet network and the interface card is letting you know it.  Poor connection, damaged DeviceNet media, one too many nodes attached.  DeviceNet is very rugged and robust, but I have seen many DNet networks show signs of failure and nobody has a definitive schematic of the network.  Do you have a good schematic?  Start going through the network looking for physical signs of failure, pinched trunk or drop lines, poor connections.  We had a similar failure; root-cause - someone pushed the SCADA computer too close to the office wall, shoving the termination resistor to the side and making a poor contact.  Had it not been for the cleaning lady, the problem would have never occurred. 

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Thank you very much for the valuable replies. Thanks for the pdf Mr. Alex.

And Mr. Will, there are so much cables going from this problem giving devicenet scanner module. So maybe I have to check all the cable connections from this module right? Hopefully I can find it and fix it. Thanks you again.

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Akif I have been in your position, inheriting a DeviceNet mess "that worked".  Working around production, myself and our technicians isolated a DNet connection point, monitored the network to find out where the break was, and took good notes.  It is easy to separate the network and ring out wires.  However it usually means "breaking" the network, which might affect production.

Dig into the DNet module to find diagnostic history.  Work your way backwards.

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Oh, Okay. I don't have any Devicenet meter with me, I don't know whether I need that. Can I with the help of  my people here physically check for the bad wires or the cables, working backward as you told?

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