Help with my "Linxcnc for Dummies" web page.

Looks like it supports +-10V input for bi-directional control so as a first shot:

STF --> 7I77 ENA5+ (22)
SD --> 7I77 ENA5- (21)

1 --> 7I77 AOUT5 (24)
5 --> 7I77 GND (23)

PR 73 must be set to '1' for bi-directional operation

Be aware that VFDs are notoriously noisy so you may need a common mode choke
on the AOUT5/7I77GND leads to the VFD

A common mode choke for this application is basically a large ferrite bead
with the 7I77 AOUT5 and GND pair fed through the middle

I have it wired now however the hal configuration is an issue.
I took a wild stab at it based on a regular axis.
Probably doesn't use pid.
I doubt I am even close.

net vfd-enable pid.5.enable <= axis.5.amp-enable-out
net vfd-command pid.5.output => hm2_5i25.0.7i77.0.1.analogout5

linuxcnc.org/docs/html/examples/spindle.html

has some examples

Since you are not going to be using a PID loop to control the spindle speed it should be pretty basic:

net vfd-enable motion.spindle-on <= axis.5.amp-enable-out
net vfd-command motion.spindle-speed-out => hm2_5i25.0.7i77.0.1.analogout5

You will also need to scale the analog output to match your spindle top speed at +-10V:

setp hm2_5i25.0.7i77.0.1.analogout5-scalemax 5000
setp hm2_5i25.0.7i77.0.1.analogout5-maxlim 5000
setp hm2_5i25.0.7i77.0.1.analogout5-minlim -5000

Assuming 5000 RPM is the spindle speed with a 10V
command and you want the spindle to be reversible.

Ran into that "pin does not exist" error again.
it was on:
axis.5.amp-enable-out

Is there something needed in the INI file for axis 5?

sorry that should be

net vfd-enable motion.spindle-on => hm2_5i25.0.7i77.0.1.spinena

BTW when linuxcnc is up and running
I would do a:

in a terminal window so you can know what
hal pins and parameters are available

Axis is back up and running.
Unfortunately the VFD is still looking for the encoder.

The part of the instructions for changing to V/F control says:
Short circuit across terminals MC and SD ...the operation will change to "V/F control"

I can't find a MC terminal anywhere and assumed it was the 3 digital terminals but since it is not switched over
probably not. This is the only thing left that I haven't done.

Not sure what they mean by "Short Circuit". Sounds bad.
Can't find MC.

Found MC terminal.

It is DI1, DI2,DI3.

Now the tricky part:
Says "Speed, torque, or V/F control can be selected with this parameter (Pr. 14)
and switched between with the MC terminal (DI1, DI2, DI3).

Do you think I have to short circuit one of these pins with a wire to "SD"?

Sounds like it to me but "Short Circuit" is not something I want to do without checking.

All the digital inputs are actuated by being connected to SD so this is normal

Looks like pr99 is involved in this also

This is harder to get the VFD working without the encoder than putting one on.
If someone can attach a working hal section for a VFD with encoder I will just wire up the encoder today and hopefully be finished.

I've been working on my web site and need working hal sections for both encoder and non encoder VFD spindles anyway.
I'm pretty much limited to cut and paste hal file construction. I have to raise the white flag and surrender on learning hal.

I have the VFD with encoder hooked up and the errors went away. Reading 0. I assume 0 rpm.
Worried my VFD was bad but looking good.

I still need (Soon or Eventually) a good VFD with encoder HAL to copy. If someone can post a link to one that might do the trick.
Looked at the manual pages and the VFD section is complicated beyond belief. I definitely need to copy one.