Troubleshooting Bus Faults on a Devicenet System?

Do you have a CAN bus analyzer? It would allow you to look at the traffic on your network and should show faults as well. Check with the PLC maker and see what they recommend.

Yes we use a bus analyzer, but it still is difficult to pinpoint bus faults. The last time we had the problem we hooked up the analyzer and it pinpointed the problem @ node 6 then node 7. We spent allot of time tracing wires at these points, yet we found the problem to located at a different location. The analyzer basically just verified that we had a voltage drop and was no help pinpointing the trouble location. I was hoping there is some input on an easier way to find bus problems.

I was thinking more along the lines of using the analyzer to determine which nodes weren't communicating properly... then you could check the wires between the nodes for problems. This was assuming it was a purely physical problem.

What and where was the root cause of your last problem?

After inspecting all the prox cables, sensors, pneumatic valves and other field devices, we inspected the main trunk and found a 1/8" bare spot in the bus duct. Intermittently. the bare spot would touch the metal bus and go to ground. It was a problem off and on for a couple of months, so I went ahead shut the system down until the problem was found