usb6560 Axis4 - Spindle speed

[AndyUK]

I would suspect that the "pin number" is referring to the microcontroller, or the simulated LTP port, so its not straight forward. Pin 1 goes to that relay, and by the looks of things pins 2 and 3 go to the Mist and Flood pins further up.

I could be totally wrong, but my suspicion is that when the controller gets an M3 code, it closes that relay. That means COM and A are connected, and COM and B are not connected. When the controller gets an M5 code, the situation reverses and the relay opens. That means COM and A are no longer connected and COM and B are connected.

I can't see any spindle speed output on that controller. It looks like just an on off switch. But again, could be wrong...