I'm setting up the spindle output for something other than a spindle and just need a user variable PWM output to the spindle step pin.  

What triggers Mach3 to begin the PWM pulse train?  

Once the pulse train is started, would I change it using the S word or by entering a value in the spindle speed DRO?

Thanks

Basically, all I need is a PWM output from Mach3 into a DAC, like a spindle control board.  The PWM output would be scaled from 0 - 100 and as I change the spindle speed, the voltage should change.  0 = 0V and 100 = 10V.  Looks like to do this I would go to Config -> Spindle Pulleys and set up pulley 1 as min Speed = 0, max speed = 100.  Then go to Config -> Ports & Pins -> Motor Outputs and set the port and pin for spindle step.  I'm not using a direction control, so I left the dir pin and port at 0.  The Config -> Ports & Pins -> Spindle Setup and check "Use spindle motor output" and check "PWM Control".  Base Freq. is set to 5 and min PWM% is set to 0.

Now it's possible that the process that starts the PWM pulse train is not happening.  I thought DoSpinCW() and DoSpinCCW() start the PWM output and DoSpinStop() stops it.  When I execute DoSpinCW() from a macro, I read .5V from the spindle board regardless of the spindle speed setting.  The board is a CNC4PC C41.  I have 24V connected to where it says to connect 24V.  5V connected to power in.  The only other connection is the analog output.

Hi,
 Have you gone into the spindle setup  and setup the parameters?

Having defined the pulley values as you indicate (0, 100), then TWO more things are needed.
First, S50 will set the PWM (to 50%), but it won't appear yet.
Then M3 will enable the PWM output, and M5 will disable it.

Cheers
Roger