Laser won't turn on on 0.92.8

Hi Repetier,
I am trying to get the laser to work on 0.92.8, but the firmware keeps it off (if I set it to "High Enable" or vice versa, it keeps it in the OFF state anyway (thus I'm sure the pin is correct)) during both G0 and G1 moves.

What am I doing wrong?

My Configuration.h:

Thanks in advance.


  • Did you send M3 to enable laser at all? Only after that G1 will enable laser during moves. Also make sure you are in laser mode (M451). Otherwise it looks right. You could test with a multimeter on long slow moves if you get voltage (polarity). Not that your laser does not work properly. Mine needed a extra board with 12v and a controlled it with a 5v ttl signal.
  • Ooh, dang it...
    Thanks Repetier and sorry for the noob question. I never tried sending M3!
    Now everything is working.

    My 2W laser module from China takes 12V 1A from a LM7812 regulator and it seems OK. The TTL works like this: on the laser module the input is pulled up to 3V and the laser is ON. When I short it to ground (I do it with a RAMPS onboard transistor) the laser turns off.
  • edited January 2016
    I got the laser to work, but still have weird issues...
    Sometimes (after homing and after I plug in the power) - not always - the laser keeps on working even after a M5 command.
    Anyway, please explain the behavior of the following:

    If you have a laser - powder system you will like your E override. If moves contain a increasing extruder position it will laser that move. With this trick you can use existing fdm slicers to laser the output. Laser width is extrusion width.

    Is it even implemented? If yes, how to enable this feature?
  • Sorry, can not explain the homing thing. I know my laser turns on while burning a new firmware. Maybe the port still gets some power somehow.

    The e override is always active and should work. It is independent of M3 so you do not need to turn on with M3 in that case. 
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