Denford Novamill Mach3 conversion

[JohnHaine]

I think you're being a bit categorical here Irving! You can't rely on a limited slew rate to do the smoothing for you. And your comment on ground referencing isn't helpful because by definition "signal ground" is what the control inputs are referenced to! The question is, can the 0v on the controller be safely connected to the signal reference on the vfd?

The Novamill does not use a vfd since the motor is a dc permanent magnet type and the original controller I think is thyristor based. There may or may not be isolation between the trigger circuit and the speed control circuitry, on the KB Electronics one I have there isn't.

Miller, I suggest that you ask the question on the Denford forum, denfordata.co.uk .