Looks good. I could do with a box like that to put a coolant pump I acquired in.

Quote Originally Posted by Web Goblin View Post
I need to have a read through the VFD manual now to see what to set up for it to take an external input for start/stop and speed control.
Should be able to do it with the input the pot uses. Substitute the pot for the parallel port pin and use PWM output in mach. I'd put a capacitor (and possibly resistor in parallel) at the VFD from that pin to ground to smooth the PWM. It's all in the manual... you can do it with digital inputs but you probably wont have enough I/O on the parallel port to do that.