I have set the limit switches to trigger the direction prohibit functions on the drives. By using the Normally open contacts as well, Mach3 will get a home ref input when any of the limits trigger. I have got the Servo Alarm circuit to cut the power only if sh*t happens.
[nomedia="http://www.youtube.com/watch?v=zWeaBt_-gsM"]YouTube - Mill first test run[/nomedia]