Pairing up Mesa 7i76e with VFD Delta C2000

ACM to pin 1
AVI to pin 2
10v to pin 3

I tried wiring as you said and its still not working.
I will attach my hal file so that you guys can have a look over it.

PS: There are a few things commented out that apparenly should not be commented out like:
#net jog-x-pos halui.jog.0.plus
#net jog-x-neg halui.jog.0.minus
These are because I'm using an iMach ps4 pendant and when I installed that pendant, I had to use their hal file so they were conflicting with these.
However all the functions are working fine, I can start/stop the spindle from the pendant itself, the UI of linuxcnc updates its just that nothing happens.

From your hal file:

#net spindle-enable <= motion.spindle-on
net spindle-enable => hm2_7i76e.0.7i76.0.0.spinena

spindle-enable will always be false

So you're saying that it doesn't work because spindle-enable is always false?
I am using an USB pendant form iMach P4s and for that I needed to add the hal file in the attachement.
When I added that I had various conflcts that some pins are already used so I had to comment them out in the SyilX7.hal
You can see in the file attached below that spindle-enable is set in this file.

Regarding direction, my VFD does not have a enable an direction pin, instead it has DCM that needs to be connected to either FWD or REV in order to spin.
So basically I would need some kind of a relay functionality to control the direction.
Can I achieve this functionality using the pins from TB4 connector?

Indeed after uncomenting out the spindle-enable, the potentiometer functionality of the mesa board is working.
However now I have two challenges
1. How do I switch between FWD and REV?
Like described in a previous post, I have made the wiring this way:
FOR to Pin 6 (spindle enable+)
REV to Pin 8 (spindle dir+)
DCM to Pins 7 and 5
Right now it works only on forward, because when I hit spindle FWD, the spindle-enable will activate the potentiometer and will cause the pin 6 to be ON.
When I would need to run REV, I would need to connect DCM to REV, but spindle-enable would still need to be ON because I need the potentiometer to work.
Is there any way I can achieve the FWD/REV functionality without using these pins? I don't know, perhaps by using some of the outputs that mesa has?

2.I have some issues between the commanded speed and the actual speed of the drive.
I have set the min and max limits to 10 and 10000rpm and the outputscale to 10000
I am monitoring the pins that are reflecting the commanded speed. The results are not linear and I don't know why.
See below the results between the commanded speed and the actual VFD speed:
101 ... 7rpm
201 ... 115rpm
301 ... 222rpm
401 ... 329rpm
501 ... 436rpm
...
1001... 968rpm - here its still below the commanded rpm
2001... 2039rpm - starting from here its above the rpm
3001...3110rpm
4001...4190rpm
5001...5256rpm

Please advise!

I forgot about that, i will try it tomorrow.
Any suggestions about point number two from my post regarding commanded vs actual speed?
The values I have now are:
setp hm2_7i76e.0.7i76.0.0.spinout-minlim 10
setp hm2_7i76e.0.7i76.0.0.spinout-maxlim 10000
setp hm2_7i76e.0.7i76.0.0.spinout-scalemax 10000

After I changed the VFD settings, it worked! Now it spins in both directions. Thanks!

One problem remained is the one related to the speed.
Right now I'm investigating to see if I can obtain an encoder output from the resolver input. The VFD has a plugin board, that in spec should output encoder signals. See attached the spec of that board.
Using an ethernet cable with twisted pairs, I have connected it to the AA' BB' ZZ' and tried monitoring with a friend's oscilloscope.
I have measured the A channel, I see a square wave, quite noisy, but Vpp (voltage peek to peek) shows 15volts...and this seems a bit odd to me because the documentation of the board attached below says its only 5v.
Also how do I figure it out what's the resolution of this encoder?