uc300eth vfd connectios

[Doddy]

I'd be looking at the RS485/ModBus controller (available for UCCNC and Mach3) - at least to see if it's viable for your VFD. It avoids some of the problems with analogue noise, linearity, etc.

There are a few ways to use the UC300ETH for VFD speed control - the usual PWM output on the more typical BoBs, the analogue output that Jazz covered, as well as the above suggestion to disregard it altogether.