I'm trying to get Mach to operate the on-board relays of the C23 BOB to be used to for run and direction control on my VFD.

I M3 and M4 commands assigned to output 1 and 2 in spindle setup and the 'disable relay' box is unchecked.  Output 1 is assigned port 1-pin 16, output 2 is port 1-pin 1 as directed by CNC4PC documents. 

I cannot get the relays to switch.  I've been checking by measuring the ohms of the terminals.

I'm at a loss here...as I have been a few times already.  I'm ready to shovel all these magic boxes into my mill once this is solved.

Any assistance would be greatly appreciated.

Digging a little deeper,  I shut the board down and applied 5v directly to the coils of each relay.  The relay assigned to pin 16 does switch, the other relay appears to be dead.  Though the pin 16 relay functions in this manner it does not operate via Mach and M3 command.

I'm stumped.

This discussion has now moved here;   http://www.machsupport.com/forum/index.php/topic,32186.0.html

Tweakie.