Strictly speaking you only need full isolation where the analogue input control is not galvanically isolated from the incoming supply as in the KB DC controllers, it is very rare now to find the +12 v etc on the average VFD that is not isolated.
So far, the BOB's that I have come across have PWM to analogue isolation anyway?
Or are you referring to other pins on the P.P.?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.