I know OEMDRO 83-88 are the machine coordinates for all 6 axes, but what are the OEMDRO numbers for the 'non-machine' coordinates. I looked through the programming manual and tried 'Work X' etc, 'Part X' etc in a macro to return their values; nothing matched what I see in my DRO's on screen. I have no idea what I'm looking for.

M21

X=800
Y=801
And so on.

http://www.machsupport.com/Mach3Wiki/index.php?title=OEM_DROs

I wouldn't have even guessed that! I like how it returns whatever you see in the DRO, regardless of whether machine coordinates is selected or not. It's clearer in the wiki.
Thanks