More Z-Axis Issues

Are you running a Run In Place or a Buildbot version of LinuxCNC?

It's build bot. The last I updated was on October 20th.

Next time it stops like that, before you try to restart can you:

note the exact error message
note if there are any errors in the terminal

Yes I home the machine. I will see if I can pause and resue while cutting but it will be tomorrow before I can get back out to the shop.

Here is a video I made of it messing up. Hopefully it will shed some light on what is going on.

Man that is odd, this is grasping at straws but did you run Configurator in upgrade mode after your last update?

I have not run the plasmaC configurator since I converted my base machine. I've just been modifying the ini and hal files myself.

I did not notice this until I watched that video a couple times just now. The first time I hit the pause button the code jumps from line 909 to line 912. The last line it ran was 911 which is G00. Since G00 was throwing errors on the g-code parser, do you think this has something to do with this problem as well?

Did you try the postprocessor I sent you to see if it behaves differently

No I have not tried it yet. I will try it and some of your other suggestions and report back here the outcome. Will have more time to mess with it on Saturday.

Ok I've been able to try a few things. Here is what I have done.

1) Updated LinuxCNC in Synaptic Package Manager.
2) Ran PlasmaC configurator in update mode.
3) Installed your postprocessor in sheet cam.
4) Recompiled my gcode using your post processor.
5) Tried to load it in LinuxCNC as .ngc and got error "*" not valid character. I searched the g-code and there was no * in it.
6) Renamed the file to .tap so it would bypass parser.
7) Loaded it in LinuxCNC again and got error "Material 1 not in list". So I commented out lines 11 and 12 shown below.
8) Re-ran g-code in linuxCNC. Gantry moved to position of first cut, touched off and then stopped at line 19. The play button showed that it was still running, but nothing was happening on the machine or on the screen. If I hit the pause button, it acted like the program paused, if I hit it again, it acted like it resumed. This is the same behavior I showed in the video when the "lost arc" error occured.

9) I loaded the g-code with my post processor and let it run with torch disabled. I hit the pause button while the program was running and the execution paused. Then I hit resume and it resumed right where it left off. So the pause button works correct if it is hit while the program is running..

; DogMom_PhillC.ngc 03/11/2019 16:45:59
; postprocessor: PhillC.scpost
;
G20 (units: inches)
G40 (cutter compensation: off)
G90 (distance mode: absolute)
M52 P1 (adaptive feed: on)
G64 P0.01 Q0.001 (tracking tolerances: 0.01")
F#<_hal[plasmac.cut-feed-rate]>
;
M190 P1 (plasma 16ga material)
M66 P3 L3 Q2 (wait for valid change)
;
F#<_hal[plasmac.cut-feed-rate]>
;
(start dogmom #1 torch, 9.15")
G0 X7.33058 Y4.76151
M3 $0 S1
G3 X7.43430 Y4.67392 I0.09566 J0.00806
G2 X7.58259 Y4.66736 I0.04872 J-0.57797
G1 X7.58299 Y4.66729

This is as far as I have been able to go. I will try creating a new machine as you suggested and see if that fixes the issue.