CM changes the Z on Pause/Stop

Last night I was running a program doing a pocket, everything was zero’d in just fine and had started cutting. I got interrupted and needed to leave the machine. I paused it, then stopped the program rather than leave it running. When I came back I started running the project from the beginning, expecting it to cut air until it got to where I had paused/stopped the previous run. Instead, it started cutting twice as deep as it should have. Stopped the machine and re-zeroed and my zero was about 4.7mm lower than it should have been. Since I was cutting a 0.1855 (4.7mm) deep pocket, seems like it picked up the bottom of the cut as the zero. The XXL and laptop had stayed powered on with CM still running.

Should I check the zero every time i stop a run, or was that just a one time weirdness?

How did you set zero initially?

In the usual way… After it ran the homing program, I zeroed off the bottom left corner of the material for x & y, then used the post-it note method to zero Z off the material top. When I paused/stopped, it ran the homing program again like normal.

After homing, if your Z zero is consistent, it sounds like either your original zeroing wasn’t a permanent one or something happened when you zeroed initially. I don’t use Carbide motion, and I’m not near a computer, but I think it uses a G10 L20 command to set the zero offset. That should persist until you explicitly change it. Do you know the command CM sends for a zero?

No idea what CM sends to the machine, I assume it’s the same thing. Might have just been a weird glitch. Hopefully it won’t happen again. I’ll be sure to check my Z after I stop mid program

When you pause or stop does your Z axis drop?

Not that I noticed, it retracted normally for the pause, then went through the homing program when I clicked stop.