Getting my mach3 / TAIG going again....z home problem

[macdarren]

HI All,

I am getting my mill going again after about a year away from it. I am resurrecting it with a new enclosure and I went through the mechanicals etc. I've had several issues and most I got worked out, but my recollection of how Mach3 works and is configured is not so great. I also have a smoothstepper just to complicate matters.....

So my Z axis problem is this....maybe it has always been this way I don't know but lets say do an all home (I have limit/home switch for the Z axis at the top of the column) everything homes fine X,Y, and Z it moves to the switch, the switch trips and then it backs off a bit. Here is the problem...if I then ask it to home Z again it will pull the head right past the switch and slam it into the stops. I think something must be mis-configured...either it is not backing it off the switch on the first home (the diag screen says it is) or it does some motion before it sees the switch again and can't stop in time but that seems wrong too. As it clearly trips the switch the second time and keeps it tripped even as it grinds against the stop. If I move the Z down some amount before asking for the second home everything is fine. Neither of the other axes do this........I Q&D fix might be to get it to back off the switch further but I can't find anything that controls that function.

On a similar note are there controls that position the head in a fixed position off of home after an all home request? Basically I would like sometimes for the mill table to centered under the head after finding the limits. I am still kinda vague on the whole limit vs home switches thing as that was the last thing I worked on before putting the mill aside a year ago and I don't really recall how far I got on it at that time and now remember even less.


Thanks
Darren

[ger21]

As it clearly trips the switch the second time and keeps it tripped even as it grinds against the stop.

If you look at the diagnostics page, is the LED for the switch lighting up as it goes past it?

[macdarren]

I believe the answer is yes....however I will verify that tonight. I know the switch lever is depressed and I can hear the switch close but I don't recall if I looked at the display to see if Mach knew it was tripped as I was usually scrambling to shut it down before it crashed the 3 or 4 times I tried to get it to stop.

[macdarren]

Okay I checked it does trigger the switch in and I can see it in the Mach diag mode....unfortunately even with the z slowed way down the watching it go past the switch and letting it slam seems to have either bent or knocked something out of whack....the z now moves with a stutter on the way down..still seems smooth on the way up...I need to examine things to see what I tweaked.

I am suspecting their is something else going on however as there are some other weird things happening, like motions I don't expect or in the wrong directions so I need to sit down with everything running in slow motion and see if I have something hooked up wrong or what.

I have the machine currently homing and zeroing at the position where the table is back against upright and with it extending all the way out to the right. From this position any movement is making positive cuts, in quadrant 1. Zero for the Z is at the top of travel and moving down is negative.

On the plus side before I slammed the head I did manage to get the relays working again, I'll call it two steps forward and one back.