DeviceNet problems

Hello,
The problem started with an intermittent F26 fault on a Reliance GV3000 drive accompanied by error 72 on my 1747-SDN scanner module. Wiring has been checked, termination resistors are good, and voltage measurements look normal.

While browsing the network (no errors on drive or scanner) in RSLinx with my 1784-U2DN module, all 4 nodes on the network eventually drop out with the same F26 drive fault and 72 error on the scanner.

Please help.

I'm not as familiar with the GV3000's DeviceNet interface as I am with the PowerFlex and others, but I've certainly troubleshot a lot of DeviceNet networks.

I'm not sure it's a DeviceNet problem, but rather that the DeviceNet scanner is one of the places you see the consequences of a drive logic board or option module problem.

F26 is a fatal fault in the GV3000, indicating that there's been a major failure in the communications option board itself, or between the option board and the drive.

If the option board was losing connection with the DeviceNet (network noise, loose network wiring, bad network power) then I would expect an "nCL" fault code indicating network command loss.

It can't hurt to get a tool that can check for intermittent things like error frames (the Woodhead NetMeter is my favorite) on the DeviceNet, but I would focus on the drive itself and any noise, grounding, vibration or corrosion issues on the logic boards.

How do you recover from the fault ?

Thanks Ken. The only way to recover is by recycling power to the drive. By the way, the drive isn't always faulted F26 when the scanner is displaying Error 72. It will run like that for days without comms to our HMI.
It's interesting that you mention the "ncl" fault. This drive sits alongside 3 others of the same type but doesn't act the same with network loss. They will display "ncl" and diagnostic LED's will flash red, but this one remains in the same state. I'll have to take this node off the network and see if I can connect the next time it faults.