VFD interference problem

[komatias]

Any ethernet socket is galvanically isolated on both sides. So it will not pass direct currently to and from the computer. The ground loop will then not be present. But if there is an issue in the wiring then it may cause issues nonetheless.

[eurikain]

Yes, but the ground loop could still flow through the cable from the BOB to the ESS, or not ?

[komatias]

It should not really unless the optos on the BOB are buggered or there is an issue on the board.

[eurikain]

It looks like the board only has optos on the input signals though. But as you said, there are so many cases of people using this BOB without problem that we can't just assume it's the BOB that's the problem ^^.