In pncconfig I've got the spindle moving forward at the correct speed. It took me hours to realize that the gear ratios in the calculator are upside down and backwards. I also had to change the max voltage to 10 to give me the full 0-5v. It must assume that your going to give the 7i76 10v and cut it in half if you select 5.
The problem now is that when I turn the spindle on in axis it just goes to full speed. If I turn it on in mdi with "s500 m03" it still just goes 4000rpm and it does it nearly instantaneously. The plus and minus buttons in manual don't do anything, but if I move the slider below 100% it will slow it down. I also can't get the spindle to run in reverse, although I'll probably never need it to.
net spindle-vel-cmd-rpm-abs => hm2_5i25.0.7i76.0.0.spinout
net spindle-vel-cmd-rpm-abs <= motion.spindle-speed-out-abs
These mean that the spindle speed command is sent directly to the 7I76
so if you set S500 , the value 500 will be sent to the hm2_5i25.0.7i76.0.0.spinout pin
No reason to use output from the VFD, the spindle encoder will be the most accurate.
Limiting spindle acceleration should be done by putting a lowpass or limit HAL component between motion.spindle-speed-out and whatever sends the analog voltage to the VFD.
