Weird position of graphic after homing and also when clicking go to position

[Madcreator (Yannick Riou)]

Hi,

since yesterday, I can’t manage to have “valid” position with Lightburn.

To reproduce the problem :

• I home the machine (the homing point is front left of my machine, corresponding on lower left on the following image, it’s a 200mmx200mm working area).

• Then if I move the toolhead around the build plate by 50mm steps, the position is fine (get position is showing something right, and the show last position also), meaning I can go around the limit of the build plate doing X:50mm Y:0, X:100mm, Y:0 (…) X:200mm, Y:50mm, etc.

• But the problem comes when I try to use the “set laser position by clicking on the page” and also the “Move to position X Y”. If I click on the position X:50mm Y:0mm, and if I check the position (get position), it show X:99mm and Y:36mm. The position of the toolhead showed by the last position on lightburn seems consistent with the one I see IRL. So the problem is why the X/Y position returned by Lightburn “get position” button is totally wrong, and also why If I click on the buildplate at X:50mm, Y:0mm, the toolhead isn’t getting at right coordinates ? When I upload a graphic and begin to burn it, it is also shifted in the same way as the previous explained position problems.
  

  

• As it can be related, If after all the above actions, I click on “go to origin”, the toolhead doesn’t return on the lower left corner (where the home was finalized and origin was set) but instead go to this position : X:57, Y:37.01. (the show laser last position and the position on the build plate IRL and on lightburn seems consistent), but the real problem is why the origin isn’t X:0, Y:0 ?!

• I found another example of these weird position problems :
  If I put a square at position Xpos:100mm, Ypos:100mm on the build plate and if I ask the toolhead to “Move laser to selection center”. On the lightburn buildplate the "show laser last position will be straight at the center of the buildplate (which is 200mmx200mm), but IRL it will be off this position.
  

  
  
  This can be confirmed by clicking on the “get position” and seeing that the toolhead is instead at X:149, Y:136.
  
  

For information, I checked that my axis are well calibrated according to step/mm, the origin is set after homing (as in the grbl configuration), so the problem seems to be about configuration of Lightburn or maybe a bug…

Here is a image of what I did to reproduce the problem. Maybe my buildplate configuration in lightburn is wrong even If I choosed a 200mmx200mm buildplate in device setting.

Thanks for your help,

don’t hesitate if my explanation was unclear (it might be),

Regards

[LightBurn (Oz)]

In the console window, type $# and press enter. If the coordinates next to G54 are not zero, you have a workspace offset applied. Use the command G10 L2 P1 X0 Y0 to clear that.

Go to Origin does not go to X0 Y0, it goes to the last recorded User Origin point:

[Madcreator (Yannick Riou)]

$#
[G54:49.000,36.000,-7.000]

Wow thanks for quick reply, it seems to be the problem. But how did it happen ? (quite new with Grbl so I may be missing things…). Is there a way in Lightburn to set this and I accidentally set it, or maybe when I launch an external gcode that had this command…

Ok for the precision of the Go to origin, didn’t know that.

thanks again, you saved me some hours of long searching !

[LightBurn (Oz)]

If you use the machine for other things, like CNC work, the standard workflow on CNC machines is to zero the working coordinates to the workpiece and run from there. LightBurn doesn’t do that because that would mean we couldn’t jog to an absolute coordinate on the machine. When you click ‘Set User Origin’ LightBurn just records the position. Later, when running a job in ‘User Origin’ mode, the first thing the software does is jog to that location.