I have a Huanyang 1.5kw inverter and spindle controlled by Mach3 and a C32 BOB.
The spindle is wired as per CNC4PC's diragram using a RJ45 cable.
The problem is that when sending a forward start command the spindle will occasionally spin up in reverse.
I have tried disconnecting the REV wire on the inverter's and it still sometimes spins up in reverese.

The odd thing is that if I run the spindle manually from the inverter's control panel it always spins up forward as it should.

Any input would be appreciated.