7i76e VFD configuration

Almost all VFD's have a setting to enable outside control, see if you can find that.

it depends upon the spindle motor and what your settings are in the VFD.

some spindle motors are designed to operate at 400hz,

check the settings within the VFD with regards to the set number of poles and its current rating and settings and also the motor frequency (from the drive to the motor).

120 * 400hz / 2 pole = 24000 rpm

Minimum frequency (setting in the drive) = 6000rpm * 2pole / 120 = 100hz

Alright, I got it worked out. My VFD has an especially bad manual, but multimeters are the best.

I ended up doing the following:
Mesa 7i76e --> VFD

Spindle- --> GND
Spindle Out --> AI1 (Configured to be 0-10V input)
Spindle+ --> 10V

Ena+ --> X1 (Configured to be "FWD" in VFD settings)
Ena- --> COM (Grounded end of VFD 24VDC supply)

I belive the way this VFD works / is currently configured is that it looks for X1 (normally at +24V) to be brought to ground. When this happens, like when the mesa closes the "enable" switch, the spindle is turned on, set to the RPM configured by the mesa's "digital potentiometer". I could spend more time poking around trying to figure out the best way to actually have direction +/- control, but I really don't need it and I'd rather spend time getting a spoil board and fixture plate machined up and mounted!

Glad you got it working.