I am having an issue when doing 3d carving that the z gets lower and lower during the cut.
We checked all the mechanicals and found no issues.
During the debugging I shot this video https://youtu.be/DPSKu8uQxPY
After running the file and stopping and using MDI Z0
the z goe to what it thinks is zero based on the dro, If I go into configure options in Mach4 and change the read ahead line to any number, The DRO resets with the actual height of the z. Running MDI Z0 now properly zeros the machine to the original zero setting.
 Attached Mach4 profile and the gcode that we found the problem.

Thanks
Mark

did you see yours gcode?
look at lines 12870-12893.....its trash

Thanks, I just re-uploaded the same file that was clean on my end when uploaded.
The bum file would not explain why Mach4 would give me the correct DRO readings when I change the read ahead lines value.

I uploaded a second video to illustrate the issue. https://youtu.be/WGCe3JjZ5NU

yours gcode go deeper(attach front view) what is yours question?

Yes it goes deeper but with the build 4809 it goes inches deeper than the gcode. The deepest cut in the project is about .5" Did you look at either of the videos? It shows the problem where Mach4 inaccurately reports the z height but shows correct heights after you change the read ahead lines number in the general controller configuration. I do appreciate you taking time to look at this.

Are you using stepper motors?
If you are I am guessing the speed or acceleration is too high

Are you using stepper motors?
If you are I am guessing the speed or acceleration is too high

Yes steppers. Dropped both acceleration and velocity down to 20
Still have issue.

Does anyone else get this in the code he posted?

N128610G1X-9.2567Y-0.2781Z-0.0581
N128620G1X-9.2302Y-0.2781Z-0.0525
N128630G1X-9.2037Y-0.2781Z-0.0484
N128640G1X-9.1904Y-0.2781Z-0.0474
N128650G1X-9.1639Y-0.2781Z-0.0473
N128660G1X-9.0710Y-0.2781Z-0.0563
N128670G1X-Éj9384Y-Z
2781Z-   N0694
®¯28680G(ß-8.911¼N-0.278à]-0.070ם
N1286ü2G1X-8.n54Y-0._œ81Z-0.rØ93
N1û~700G1X[¨.8456Y°ö.2781ZŒ.0634

128710X-8.77«NY-0.27©'Z-0.05c<
N128€D0G1X-8Qï262Y-0xü781Z-0‚Z463
N«8730G1Ý]8.6864®0.2781°†0.0436,ÐN12874ú1X-8.7ö0Y-0.2Íó1Z-0.0ÌÇ8
N12Wi50G1X-Nj7447Y-]ª2531Z-ÜÝ0428
¬ª28760G£-8.7842
-0.253^-0.047šÔ
N1287„ÅG1X-8.çT43Y-0.ºß31Z-0.1 07
N1g
780G1X?H.8908Y2É.2531Z±_.0636
ðp128790•ÏX-8.91ÆyY-0.25»çZ-0.06ò{
N128Lô0G1X-88„573Y-0c‚531Z-0©610
N€*8810G1t!9.1433¾÷0.2531uš0.0421¼N12882<–1X-9.1†9Y-0.2>;1Z-0.0^€6
N12Ž–30G1X-Ö#1832Y-ÞD2531Z-£\0404

.28840GtL-9.209F-0.253у-0.0427w
N1288±ûG1X-9.–m96Y-0.;31Z-0.:Ñ90
N1|ð860G1Xÿu.2762Y-.2531Z_].0575
½m1288703BX-9.28«Y-0.25·Z-0.06]=
N128Mf0G1X-9ò161Y-0>531Z-0L796
NËâ8890G1ýa9.3426p0.2531¥0.1000{N128900G1X-9.9805Y-0.2531Z-0.1000
N128910G1X-10.0071Y-0.2531Z-0.0971
N128920G1X-10.2994Y-0.2531Z-0.0566
N128930G1X-10.3393Y-0.2531Z-0.0508
N128940G1X-10.3476Y-0.2281Z-0.0506
N128950G1X-10.0310Y-0.2281Z-0.0949
N128960G1X-9.9914Y-0.2281Z-0.1000
N128970G1X-9.3581Y-0.2281Z-0.1000
N128980G1X-9.3449Y-0.2281Z-0.0993
N128990G1X-9.3317Y-0.2281Z-0.0850

The first gcode file was corrupt. I uploaded a clean file last night. I have attached it here.

Mark

remove the tool information at the start of the program and test it then