Help please. Dip switches and mach 3 settings

[Clive S]

From what I understand so far, I.ll unite all shieldings from all components in the utility box,

By utility box do you mean where your incoming mains is or your control box?

The star point should be in the control box and then connected to your incoming mains earth.

There are plenty of people that use welders without problems ( it is possible that the ground rod is creating a loop)

I use cat5 cable for signals as it has twisted pairs, but you can use any small screened cable

edit: there are other methods to get rid of EMI using ferrite rings on the incoming mains to the VFD

Good look with the mods