Part way through a cut my LongerRay stopped with a warning that it had been knocked/moved. The on screen prompt said to restart the laser which I did.
However restarting the laser meant that Lightburn begins again at the start of the job and does not re-start from where the cut was. Is there a simple easy way to re=start from where the job was interupted please. This has happened twice now on the same job - I had to waste material after the first and second time it happened (same job different places on the cut) I don’t want to waste another sheet of ply!
Thank you David, the video explains it nicely - although it doesn’t help me at the moment, I’m waiting for my limit switches to arrive from China! Why Longer Ray don’t ship their lasers with limit switches pre-installed is beyond me, they make life so much easier. I’d have done this job on my CO2 but it doesn’t have a pass through for larger material, with the Longer Ray being a framework its easier to move (the piece I was working on was 800metres in length)
The more important thing might be to determine what is causing the error. That being said, I have a thought. I have never tried this but it might work.
Since you don’t have a known origin point you could place the laser head at the point of failure. If it never moved from that location after the failure, even better. Go into your design and delete everything that has already burned. This will probably take some very careful node editing. Set your origin to current position and start the burn. In theory, if you deleted the correct amount of project and the head is at the point of failure it should pick up from there.
The motion sensor correctly notes that the frame has moved and shuts the controller down to prevent further damage: the intent is to stop firing the laser as the machine falls off the table.
If the frame of the machine isn’t firmly screwed down to the table / bench / work surface, then it can shake or move as the laser head accelerates: Newton’s Third Law in full effect. This generally happens with higher-power laser heads, as they seem to weigh more than the original frame and firmware speed settings can handle.
It’s also possible the motion sensor is too sensitive, so that it reacts to a tremor instead of an actual motion. In that case, you must figure out which G-Code command (likely, an M-Code of some sort), console menu setting, or app setting controls it.
These things should be better documented, but apparently the manufacturers assume it will Just Work™.
I did a sort of workaround to this. I edited my original design and removed everything that had already been cut. I moved the laser head back to the xy home and then reburned the design. It went to the first part of the design that was uncut and continued. It left me with a part cut 30mm circle that I had to finish by hand. The reason for the error is unknown, nobody walked past it or joggled the workbench it was on at the time. I was the only one in the room watching it - apart from some initial test cuts/engraves, this is the first real job I have done with it.