[Resolved]Struggling with MESA driving VFD using 0-10v 7i96s->7i76

Hi,

I'm having some trouble getting the following to work in 0-10v
-MESA 7i96s -> 7i76 -> TB4 spindle driver connector
-Folinn BD600
Pin connections are below.

If I turn the spindle on, I get the correct scaled voltage on pin 2 ie 2.5V when at 1/4 speed, however the spindle doesn't startup. 
If I pull cables S1, S2, GND from the TB4 and connect them manually I get the motor to go forward (S1->GND) and reverse (S1&S2->GND) so it seems like the VFD is setup correctly and basic wiring is in place.  But it's not working from the Linux->MESA control.

What I've tested:
When connected S1 and S2 have ~25v on them to the VFD GND wire.
When turning the spindle on S1 goes to ~0.8v, S2 stays 25v.
When turning the spindle in reverse S1 is at ~0.8v and S2 goes to ~0.8v.  (So MESA transistor(s) seems to be working).

I've tried reversing the signal -> gnd pins, it seemed to work sometimes and the motor starts up intermittently but the motor wouldn't turn off fully, it would drop to a really slow RPM (<10 rpm? ) and there was some Hz getting registered on the VFD, but no voltage on Pin2/A1 relative to ground... (earth leakage/noise potentially? I've used shielded cable and earthed it.)
I've tried using ENA and DIR pins to drive an external SSR with the same results.. maybe I need a mechanical relay?

Something I'm doing preventing me from getting a switch type of connection between S1 and S2 to ground....
Maybe I need a pull-up/pull-down resistor??.. (FYI if it's not obvious I'm not really confident with electronics, ok with electrics)
Maybe I need to run multiple ground wires, currently I'm sharing the one wire to the VFD as my cable was 6 core shielded not 8.


Note that I tried to get it running via VFMOD and didn't have any success, I was told that the modbus is broken in the latest firmware by Conan motor (in AU), F07.09 = 30.012.  But it could also be the ebay RS485 usb driver.

Thx Tommy
I had tested the scaling using the m3 s1000 as well as via the UI.
I also had Halshow up watching the spindle pins, velocity/rpm and MESA outputs which all looked to be ok.
 Very open to any other ideas suggestions as well.

If the FWD/REV wires switch from ~25V to ~0.8V and the Analog out is about right,
there's nothing wrong with the 7I76, Sounds like wiring, VFD setup or VFD fault.

I rewired it w/8 shielded cores and still have the same problem.
The voltage drop improved and went to 0.75 (was 0.82 or thereabouts).

I found I needed to increase the VFD signal delay time (was looking for a voltage threshold but didn't find for S1 or S2), F05.12 = 0.010s by default, changing it to 0.030s seems reliable.

Thx for the help.