Just making sure I'm doing this right. Feedback appreciated!
The PWM negative is connected to -Vin? Or does this mean OPTA chassis Gnd?
On some devices all “GND” or “V-” pins are connected together. Idk how it works with that expansion, but you can simply use multimeter (diode/continuity test) to check that. If there is continuity between -Vin and GND then there should be no difference where you are connecting “zero” potential.
No continuity... hm.
The diagram is wrong. Missing -Vpwm goes to -Vdd. Or whatever your power source negative is called. GL.