Hi Noddy,

I am sorry that I cannot advise you from experience. I use this board, but only to switch a Kress using an external relay board controlled from a spare output (A or B step, but I can't remember which).

If you have a multimeter set it to volts DC range 0-20v and I would put it on the + and GND to see that you get a voltage up to 10v proportional to the speed setting in Mach3. If that is not so, then you need to look at Mach3 settings. If it is OK then you need to check the VFD connections and parameters.

That multimeter check should indicate which way to look (first).

Cheers,

Rob