I'd guess that the problem is you're switches tripping. You need to fix that first.
When Mach3 stops due to the limit switch, the mill is not even close to any of the limit switches. I'm pretty sure that the switches are tripping because of noise in the wires. Right now, due to the small number of inputs on my breakout board, I have all the switches wired in series (normally closed) and connected to a single input. As a result, there is a long (unshielded) wire running between all of the switches.... lots of room to pick up interference.
I've got a breakout board, PCI parallel port card, and shielded 2-conductor wire on order so that I can connect each switch to a unique input. Hopefully this will either (a) stop the problem entirely, or (b) let me figure out which limit switch keeps tripping.
Does anyone know if the limit switches could be the cause of the problem? As I said earlier, the wizard saves some data points after the limit switch is tripped, but not all of them.
Kyle