Help with homing and limit switches.

Thank you in advance for helping me with the following question.

The cut quality has degraded a little bit on my plasma CNC table. I believe (after exhausting all the simple issues; dry air, consumables etc.) that the gantry may be a little out of square. When I home the gantry both sides contact their respective limit switches at the exact same time. When the gantry moves off the limit switches the one axis moves and stops and the other side of the gantry continues to move a few more steps than stops. You can see and hear the gantry home to the limit switches with one click, than the gantry moves off the limit switches and you see and hear on side of the gantry click and stop and the other side of the gantry continues to move a little further (say 1/4") than clicks and stops. There is no tension or twisting of the gantry.

So, is there a problem with a limit switch or has the macro programming (witch I have no idea where to look) changed?

Any help would be appreciated.

did you use the 2.8.pre
what os are you using stretch wheezy
self compile

Thank you for your reply.

Command CNC II-A, Linux CNC V2.7.11

It's a Starlab table. Great table, good help. I'm trying to tackle this issue from two angles to get back to square a quickly as possible.

As I mentioned in my opening post the gantry touches both limit switches at the same time when homing. Its when the gantry moves off the limit switches, one side drives/steps move a little further than the other side. Is there somewhere in the programming that that tells the motor how far to move off the limit switch after homing? So that I can adjust the time, distance or steps to make both sides equal again. Or is all this information internal to the limit switch?

gantry homing is only at 2.8 pre
so you will not have luck
forum.linuxcnc.org/38-general-linuxcnc-q.../32880-gantry-homing

HOW TO is here
forum.linuxcnc.org/49-basic-configuratio...-linuxcnc-2-8-master

CommandCNC is only released on 2.7.xx for 32 bit Ubuntu as far as I know. The gantry is handled by the old gantry component which I don't remember how to use (look in the 2.7 docs). Because it is CommandCNC I don't know if you can directly edit the. ini file with a text editor. I think you need to check your with the configuration program that all the settings are still correct. Are you sure your switches haven't moved and that you are not loosing steps on one side? These mechanical things are the most likely to occur with use.

John

Thank you guys for the reply. Sorry for the time in between comments, I was at work for a few days. I just purchased new limit switches. I'll let you know when I hook them up if they improve our situation.