Gcodes with M4 instead of M3

I have added a Lazer to my engraver which uses Mach3 as a driver. As the engraver motor will never be reversed and the engraver and laser are both mounted at the same time I use M4 for the laser and M3 for the Engraver. Can there be a GRBL-M4 option or is there any where I can set to output for to be M4 instead of M3?

What device profile type are you using? As in one of these:

Hi I am using the GRBL-M3(1.1e or ealier) as this gives me the M3 output. I can edit the Gcode to change M3 tio M4 but it would be nice to have this as an otiuon in the device preferances. I am using a Mach3 to control the engraver/laser so cant use the ($32=1) option to turn the laser off during a rapid move as Mach3 does not understand the G0 and move with laser off and G1 as move with laser on.

The generic ‘GRBL’ option uses M4 by default.

Agreed GRBL uses M4 at the start to turn the laser On and M5 at the end to turn the laser Off but it also outputs G0 to move with laser turned down (effectivlly Off) and G1 to move with laser at previous high setting (effectivally On). Mach3 does not reconise this so it needs and M3 or M4 On Move and M5 Off Move. GRBL-M3 does this but only for M3 and I woulkd like an option to select a gcode output with either M3 or M4. Is this posible?

If you use the regular GRBL profile you can select “Constant Power Mode” per layer which will force it to use M3 for that layer

Thanks but its M4 that I need

At this time the only way to get M4 is to use the regular GRBL profile. There’s no M4 option for the GRBL-M3 profile.
So you are saying you want it to emit M4/M5 at the beginning and end of each cut move?

Yes Please

Unfortunately that’s not possible at this time. When using standard M4 GRBL mode, it only emits M4 at the beginning because it assumes the laser on/off is controlled by G1/G0
Could you remap the laser control to something like M106? We use that for the linuxcnc profile which does turn it off before G0

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