In this mode Grbl handles the laser power you set the laser power once, set the cut feedrate, and Grbl scales the power during acceleration, corner slowdowns to maintain a constant intensity. This is actually different than the Duet laser mode. I'm unfamiliar with LightBurn, but a 1minute google implies it defaults to code for GRBL (cnc firmware) with laser mode on. Welcome ot the wonderful world of CNC gcode and flavors. G1Y760 <<<<

M452 P3 S1 R255 F60 Enable Laser mode, on output 3 (heater 3), with max intensity being 255, and a PWM frequency of 200 M307 H3 A-1 C-1 D-1 Disable Heater output on H3

My question is, is this how the duet works or is my code the issue. Lightburn appears to presume to preserve the S value for the next G1 move. This works well, the issue I'm having is every time there is a G0 move it turns laser off as it should but the next G1 has to have a S value to trigger the laser again. I use lightburn to produce the gcode and edit the code to turn put duet in laser mode etc. Hello, found this forum a great help hadn't had to ask a question up till now as the same questions had been asked and answered.

Lightburn software vs picengrave