Trent I included a quote from Jeff below that needs just a bit of caution depending if you have done all your setup in configs and diagnositcs.
"I think this is the same thing as referencing the axis."
I don't know if Jeff is reffering to the ref all button on the main page or not, but if he is and you have done all your setup the ref all button calls for a limit switch seek within the program. If you don't have limits you had better have hard stops.
A quick and dirty way to set the machine to zeros after you jog to your know starting position is to do a G92x0y0z0. Be sure if you use this that you always clear the G92 with a G92.1 after you have finished the program or include it on the end of the program itself.
I would bet my left uh......big toe
that Jeff is far advanced to me in the use of cnc controllers and Mach2, so Jeff no disrespect meant on the warning of the reference thingy!
Mike