JAZZCNC
Thanks for your help and it has got me further then i was but i am not sure to do now
Edited: After reading Nvem Manual little more.

However this would mean you have to tie the VFD control logic Gnd which is Terminal PC on the VFD to the same supply Gnd that the Nvem uses.
(this bit I'm not sure about now because I would have expected the Analog Gnd to be separate to the Output Gnd and it doesn't appear so reading the Nvem manual.?)

You may be better and safer for the VFD using separate relays controlled by the Outputs to control the Run/Stop on the VFD by running the VFD connections thru it's contacts.

All your basicly doing is using Outputs 1 & 2 on the Nvem to turn on/off the RUN signal on the VFD by shorting STF/STR to PC(Gnd).

Then it's just a case of setting up the Outputs for Forward/Rev and Pulley speeds in Mach3 which the manual should tell you how.

Hope this helps.

do i need to use relays as the power supply for the Nvem is 24v
Thanks Dave