Mesa 5i25 & 7i76 to GE Af-300 VFD?

Short the fwd pin to the CM pin, test in Linuxcnc if you can control the speed. Since you say only m4 will activate the pindle, you do not have it set up properly. It has to be set as a spjndle in hal to be able to control the speed, mist and flood only have a pin without the speed part.
I think you can wire the ena+ to the fwd pin and ena- to the CM pin, or the other way around without a relay if you need only one direction.

There is another pin you need with that drive. I thinks it cmw or something, i will check later when i get to my shop.

The other pin needs to be tied to cm and it needs to be n/c and open to stop. So use that fwd when spindle gets enabled then use the other signal to pulse a stop. I am pretty sure the fwd is a pulse also. Will check later tonight.

This is not true, on mine there is another pin,

So if you are using 0-10 spindleout connect to pins 11 and 12 observing plarity. I would test with batteries say two aaa give you 33 percent of you max speed.

But you have to close 24v to FWD. if you want reverse, then close 24v to REV.

It seems you have to check the setup because you can change the requirements of x1-9

That should make it work. I didnt use ena. I connected a relay to motion.spindle-on and closed my fwd.
Easy, one relay for fwd and one for rev. No fuss no muss.

Here are two solutions in schematic format (see attached), the one relay solution is the solution that was suggested in the previous replies..

The one relay solution is simple, sweet and the list costly but if something goes wrong with the VDF you might end up damaging your mesa card. The two relays solution keeps Mesa and the VDF power supplies separated so one misshape with one card will not affect the other, the LED's in the relays will help you with troubleshooting in the future and if enable works backward you can reverse the logic.

So now you have worded solutions by previous members that replied to your inquiry and visual solution.

Good luck

Many thanks to all who replied. My additional relays arrived, and I went with the two relay solution keeping the VFD and 7i76 voltages separated. I now have the rest of the machine to sort out.

Again, thank you all.

-Mike

I snuck in some time on the CNC this evening. Here's a head scratcher: Using the manual control screen in Axis, I can turn on the spindle CCW (F10), but not CW (F9). The CW On the MDI screen, I can issue an M3 or M4 and the spindle works fine. Any ideas?

Try m3 sxxxx where xxxx is desired rpm