Logic assignments for VFD/Spindle control and EStops (7i96s)

Another option if you don't want to reconnect all the  switch commons is to
add an external 24V pullup resistor to the UPF signal (say 2K 1W)
Then the UPF signal will be a positive voltage that can be detected
by the 7I96S inputs when the input common is ground.

+24V --> Pullup resistor pin 1
UPF --> Pullup resistor pin 2 and 7I96S input

I switched the wiring around since it was easy.
Ill work on the vfd stuff next and report back.

PCW wrote:

Yes. the UPF and DRV outputs are sinking (pulldown) outputs.
If you wish to wire these tot a 7I96S isolated input you would need to connect the 7I96S input common (TB3 pin 12) to 24V and the 24V supply common to DCM.
The VFD's FOR and REV inputs must be grounded to activate so you would connect for example:
7I96S OUT4 --> VFD FOR
7I96S OUT4-  --> DCM 
 

If I attach PSU (-) to DCM, and then an output (-) to DCM, is that correct?
Isn't that the same as the output (-) to PSU (-)?
I have:out0(-) to DCMOut0( ) to VFD FOR

Still can't get spindle to be active when pressing [F9] 

I tried assigning the output to "Spindle Enable" and also "Spindle CW"  also cycled through parameters in VFD for that input between "Run", "For rotation", "FOR/REV"  for each iteration. 

Should i be able to meter any output voltage between Out0( ) and Out0(-) when active (when LED is on)? 

Before connecting to the 7I96S outputs, I would verify FOR and REV operation
with a switch, when this works, you can replace the switch with the appropriate
OUTN+,OUTN- pair (the OUT4,5 don't care about polarity but OUTs 0..3 do))

Where would the switch go in that "circuit"?

PSU(-) to DCM
and
PSU (+) to switch to FOR


then check PSU(-) to DCM
and
PSU(+) to switch to REV

No PSU involved at all, look at the switches in the drawing,
the switches are simply between FOR or REV and DCM.

I am not getting the VFD enabled when connecting:

DCM to FOR
And
DCM to REV
(both switches closed) 

I have VFD parameters set where FOR is "run" and REV is "For/Rev" as described here:
www.diycncdesign.com/linuxcnc-2.8-huanyang-vfd.html

So I'm not sure if there's something wrong with the hardware (i don't think so because all other functions work as expected), or there's still something I'm missing (the more likely scenario). 

Does sound like a setup issue with the drive since the same wiring worked in the linked page

You were correct!

My VFD parameter PD001 was set to 0, instead of 1.

I got the enable command working by connecting Out0(-) and Out0(+) to DCM and FOR respectively.
Ill move on to the other functions and see if they are operational now too. (Both inputs and outputs)