Hi Ed:
In Darwins config, turn on an output on pin #8, call it SpindleFreq as a name. Set it to frequency control if you see a checkbox, ( been awhile Im not sure there is one anymore)
Now, in Mach4, under diags, there is a selection for Darwin, in it, select a Frequency Spindle and set minimum and maximum frequency you wish to use.
Then, in the config/Mach menu, select outputs, way way down the list is Spindle, turn it on, as device select Darwin, and then under mapping select the
named signal SpindleFreq.
That should be all you need. Make sure you dont have laser mode selected in Darwins diag config.
When you command a spindle with M3 or do a S100, look in the error history in the tab on the bottom of the main window, it will show messages from Darwin
about what it did for the spindle commands. "Set SpindleFreq to 100" for example..
As for DIR, you can make an output and name if SpinDir, in Mach4's config, turn on Spindle Direction and set it to Darwin, mapped to SpinDir.. or whatever
you named the signal to.
thats about it,
Art