I am having an issue when I start a job and then cancel it in the middle. Lightburn thinks the machine origin is now the location where I hit cancel. Do I have a setting wrong in Lightburn?
Normally stop sends a reset command to the machine. Does your Atomstack have limit switches?
Yes it does
yes it does
Perhaps LightBurn is set to Start from Current Position in the Laser window:
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Thanks but I always use Absolute Coordinates and thatâs what itâs set to in LB.
Great choice! 
Your profile has both OMTech and Atomstack. To confirm: this is the Atomstack, right?
That suggests the machine is not re-homing after it jams to a stop. The GRBL doc suggests it may lose its position and require manual re-homing:
Look at the Console window for GRBL messages immediately after hitting Cancel; copy-n-paste them here so we can see whatâs going on.
Does the problem continue after re-homing?
Here is the error message in the Console screen. It does not happen if I rehome the machine.
Waiting for connectionâŠ
ok
[VER:1.1h.20230501:]
[OPT:VNZHDL+I,254,2048]
Target buffer size found
ok
Homing
ok
Starting stream
[MSG:Pgm End]
Stream completed in 0:01
Autofocus in progress
ok
Starting stream
Layer Text
Job halted
Stream completed in 0:02
ALARM:3
Reset while in motion. Grbl cannot guarantee position. Lost steps are likely. Re-homing is highly recommended.
ok
Grbl 1.1h [â$â for help]
[MSG:â$Hâ|â$Xâ to unlock]
error:11
Max characters per line exceeded. Line was not processed and executed.
[MSG:Caution: Unlocked]
ok
Starting stream
[MSG:Pgm End]
Stream completed in 0:01
ok
Starting stream
[MSG:Pgm End]
Stream completed in 0:01
Starting stream
[MSG:Pgm End]
Stream completed in 0:01
Starting stream
Layer Text
Job halted
Stream completed in 0:08
ok
ok
ALARM:3
Reset while in motion. Grbl cannot guarantee position. Lost steps are likely. Re-homing is highly recommended.
ok
Grbl 1.1h [â$â for help]
[MSG:â$Hâ|â$Xâ to unlock]
error:11
Max characters per line exceeded. Line was not processed and executed.
[MSG:Caution: Unlocked]
ok
GRBL comes from the CNC universe, where âcancelâ implies slamming to an immediate stop produces the best outcome and the least damage. Having the controller lose track of the current position is basically not a problem, because the operator must figure out how to move the machine safely out of the predicament.
So re-homing after cancelling is the way to proceed.
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Thank youâŠsoâŠitâs just something I need to learn to live with? Just curiousâŠ
Basically, yes.
You told the machine to jam to a stop, the controller lost track of the motor positions, and resuming normal operation starts with homing the machine to get everything back in sync.
If you press Stop, thatâs considered an emergency stop by the hardware, and it just halts the output immediately to prevent injury.
If you want to not have to re-home, press pause first, as thatâs a non-emergency, and waits for the steppers to decelerate properly. Then press stop, and it shouldnât lose position because the machine wasnât moving.
Thank you so much!!!
Thank you.
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