Z Zero routine problem

[wsaucier]

I haven't really used the shopbot here in over a year, but last week I went to use it and when I ran the z zero the router moves up instead of down to contact the plate. We don't really use the shopbot much and it's not an urgent issue or anything but I would like to know if anyone might know what the problem could be.

It is an older model, I think a PRT non alpha, I'm not exactly sure. Some time last year we added a digitizing probe but I don't think that would have anything to do with it? Other than that the machine has been pretty dormant for a year and the z zero did work before that.

[jerry_stanek]

if you move the z up about 2 inches then type in mz1 does it move the right way. If not check your unit vales to see if they are set right. If there is a negative in there then remove it or add one if not. see if it will move the right way then

[wsaucier]

The machine still operates normally, I did a crude eyeball z zero and used it for a simple cut and it worked ok. I skimmed the routine to see if anything looked off and it seemed ok, I'll dig into the routine some more on Thursday and see if I can really find anything off. I don't know if that could really be the problem as it hasn't been messed with ever.