I have a BL-UsbMach-V2.1 breakout board and WS55-220 spindle controller.

I've hooked up the controller to the PWM line (with GND and direction) and all seems to be working well. I haven't confirmed the speed is correct yet but min/max speeds are set in MACH3, M3/M4 spins in the correct direction..

this issue is, the breakout board has an AV out next to the PWM out which I can not figure out which it's for, the manual doesn't say much other that it's a positive out..
I'm not sure if i even need it as it seems to all be working.
would like to know whats it for..

picture attached with how it's wired at the moment.


Attachment 450478