Quote Originally Posted by irving2008 View Post
How far from ESS to drivers? Unless it's more than a metre or so this sounds more like a ground loop issue than induced noise. Not convinced you're addressing the right problem.
Thank you for your reply.
From the ESS to the BOB, i would say <75cm, and from the BOB to the driver <50cm

So the ESS drives the Opto-LED on the BOB, which again drives the Opto-LED in the drivers. (This is coming from converting, from Par-Port, to the ESS)
Not sure if I can skip the BOB, and use the ESS directly to the Driver Opto-LED. But for convenience I kept them......

When you say "Ground-Loop" is that from the PE (Earth symbol) so all units PSU's, PC, VFD etc. to be grounded.
And/or
All the 0V pins on all PSU's: PC-PSU, 5-12-24-48V to have a common 0V
Right now all the PSU's are running without common 0V.

Best Regards, Bo Andersen.