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Legacy Gerbil GRBL-M3 No Laser ON with M3

I have a legacy grbl controller with GRBL 1.1e hooked up to a k40 using lightburn to send g-code. I have a separate 24v power supply to drive the stepper motors and am using the 5v supply from the laser power supply to power the controller. (I don't trust the laser 5v to be clean and would be fine powering it off the USB, but don't know if there is a jumper for that on the legacy board.)

Reading other posts I made sure that $10=1 and that my power supplies have a good case ground wire.

With my current setup my laser doesn't fire below 25% power setting. With my old set up it would fire at lower % but I have made so many changes I am not sure what may have caused the change.

Connecting as a Gerbil (GRBL) device the Laser Active signal never shuts off after completing a cut.
A manual M5 does not clear it. But a M3 does - odd. I have noticed that other users have reported this issue. I assuming this is a v1.1e thing and why the GRBL-M3 Device Driver exists.

However when I set it up as a GRBL-M3 device the Laser Active signal never triggers. I am thinking it may be a GRBL $ setting somewhere?

$28=5 (Spindle freq) (I have no idea what this does need to read more on it)
$30=1000 (Maximum spindle speed, RPM)
$31=1 (Minimum spindle speed, RPM)
$32=1 (Laser-mode enable, boolean)

I would probably be fine using the Gerbil (GRBL) device driver but it is having a problem with more complex burns. I am trying to etch complex shapes at low power but the smaller areas won't burn at all. I assume that the m4 mode is adjusting the power below my 25% limit. So I ether need to figure out a way to tune my settings so it burns at all % or see if I can get it to limit to no less than 25%

Any advice would be appreciated.

Hi can you try to set the controller in CNC mode via $32=0 and retest? Please let me know what happens (M3 command is the on signal command for CNC mode, M4 is for laser mode, M5 is for switching the laser off for both)

Cheers, Paul awesome.tech

On GRBL-M3 I set $32=0 and it there still was no burn.

I tried the macro:
$32=0
S200
M3
G4 P1
M5
$32=1

No burn.

I tried the macro:
$32=0
S200
M4
G4 P1
M5
$32=1

Burn and Laser ON signal stayed active.

I saved the GRBL-M3 GCode from lightburn and changed M3 to M4.
It moved and burned, Laser ON signal stayed active.

Switching over to the GRBL device driver I tried both macros.
Both burned. Laser ON stayed active.
Repeated testing would cause the macro to work once.
Error on second run (error line 2) and clear the Laser ON signal.

Then macro would run normally.

(moved this part to a new thread)

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