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Test the laser and align mirrors mode

You can set the $31 laser mode to cnc mode which allows the laser to fire when the gantry is not moving. Great to align the laser mirrors. Issue a M3 or M4 S100 to fire the laser.

After alignment you revert back to laser mode $32=1 (laser mode). You can do this via any gcode sender. See here a few examples:



Tip for cncjs: click in the black command box to issue $32 command (not 31 as stated before, my fault). Use $$ to read out the set config. Use ? to see the gerbil status (limit switches, position etc).

Difference between M3 and M4 is CW and CCW (counterwise and counter clock wise movement of the spindle). In laser land there is no difference between M3 or M4 while executing it by Gerbil. It's just on M3/4 and off M5. The difference is done in the cutting and engraving gcode generation where the program inserts an M3 or M4 or M5. That's all.

Cheers, Paul awesome.tech

I'm having a tough time getting this to work. I can't get the laser to fire a test shot so I can align mirrors using cncjs.

I must be missing something silly. I've done laser alignment before I put the new controller in using the test switch before without a problem. Just can't get it to flash a short burst using cncjs. Maybe a short video?

You need to put the controller into CNC mode becasue the laser mode prevent firing when the head is not moving as a safety feature.

$32=0 sets it into cnc mode and you can do so via any G-code sender.

M3 or 4 fires the laser then continuously

M5 turns it off.

Cheers, Paul awesome.tech

A bit confused here. You have conflicting information. First post you refer to $31 last post you refer to $32. Which one is it? Thanks!


Yes the $ settings can be confusing and even I cannot remember them all! $32 is for the laser vs cnc mode and helpful when aligning the mirrors. $31 is the power range setting and helpful for calibrating the power output and laser tube output, see a blog about the configuration settings here What are $ Settings ?

Brian_EBA has reacted to this post.
Cheers, Paul awesome.tech

Thanks. I did find info on  the settings yesterday. But reading your posts confused me before I found the info. Much appreciated!

P.S. Might want to edit your first post and change $31 to $32 to prevent further confusion.

P.S. Might want to edit your first post and change $31 to $32 to prevent further confusion.

Done! Thanks for reminding me 😉

Cheers, Paul awesome.tech

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