Z up movement after selecting STOP

When evaluating inputs for a design I may try several iterations without completing the entire job. If I choose STOP from the laser controls my Z height is modified from the location set during cutting. This requires me to reset the Z height each time I use STOP. The movement in always in the positive (up) direction. I am using a Shapeko with J-Tech diode laser.

My Z axis controls in Device settings are all in the off position.

How can the Z height be maintained when selecting STOP in the laser controls?


LightBurn does not modify the Z height when you hit the Stop button - stop is treating as a hard-stop / abort, so no additional motion should happen when you stop. If you click ‘Save GCode’ instead of ‘Start’, you can look at the GCode emitted - if you do not have Z enabled, no Z moves will be emitted ever unless you manually click one of the Z up / down buttons, so I’m not sure what’s happening, but it’s not LightBurn doing this.

Does your controller have any $N commands registered? (type $N in the console and press enter)

Here is a video illustrating the Z up behavior with the example Gcode file listed below after selecting STOP.

Here is the result of checking the $N command:





And here is the listing with $$:




































And the Gcode from a simple line square:

; LightBurn 0.9.11
; GRBL device profile, current position
G00 G17 G40 G20 G54
; Cut @ 30 in/min, 45% power
; return to starting pos
G0 X0.45Y0.75

It’s possible that your board is disconnecting when stopping, and the behavior you’re seeing is auto-home on startup when it re-connects. I can’t think of anything else that would do that - there are no Z commands issued in the GCode, and as I said, stop is treated as an abort from us - dead stop immediately, to prevent machine damage.

Looks like it’s doing a Safe-Z movement on Estop but IDK where that would be in GRBL???

I have never seen this before - it’s certainly not a default GRBL behavior. What firmware are you running?

I’m not 100% sure how to query for the firmware but I do remember I had to update the Carbide Motion with V4 prior to installing the GRBL 1.1f.

GRBL 1.1f is the firmware version. If you got it directly from Shapeoko, it’s possible they added something to it. It’s not standard behavior.

Yea I think you might get some answers from Carbide 3d. I haven’t found much but it looks like they added retract on pause. What I’ve read doesn’t go into much detail but you could probably get an answer from them.


What CM4 and GRBL 1.1 adds:

  • Feedrate overrides
  • Better jogging
    *** Retract on pause for cleaning**

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