Laser is inverted..

  • My laser PWM is inverted, On= Off and OFF = On.. how can I fix this.? I bought an external 10W laser, and use a Eleksmaker frame and control, withan 4A 12V external PSU.

    The laser is ON only during 'moving' .. else everything looks fine.


  • Developer of T2Laser Software

    @creatron If the TTL input on the laser is inverted (that would be really bad, but with Chinese designs anything is possible) then you'll either need to change hardware or firmware.

  • I am familiar with Arduino and actually flashed the nano with grbl 1.1.3, it 'works' with programs like cnc.js, but EleksCAD does not reconised grbl. I had to flash it with avrdude to restore grbl for EleksCAD to 'detect' it. If I would know what the changes required for EleksCAD I can change gbrl source code.

    I found this 'fix' today, would this be the only change required ? ( I can program and will be able the invert gbrl program, only if EleksCAD would accept the startup.

    • The default 1.1e firmware in T2Laser has the home switches defined and all my default parameters embedded, otherwise it's the normal source.*

    #define HOMING_CYCLE_0 (1<<X_AXIS)
    #define HOMING_CYCLE_1 (1<<Y_AXIS)
    //#define HOMING_INIT_LOCK

  • Developer of T2Laser Software

    @creatron EleksCAM is old software, it only supports Grbl 0.9g. You can get that source, modify the spindle output and compile it but I don't know if it will work as they may only recognize their version (it is modified differently and I don't think they share the source - bad I know, since it's open source!).

  • @Zax I actually tried to use 0.9j, and made the changes as mentioned above, it still does not recognize it .

    What is really BAD is the laser is turned on on reset, full blast .. and this is a known bug for many moons.. it is to me a major flaw, and to rectify it would cost almost nothing (pull down resistor), a 0805 could be soldered on the 4 pin connector to fix this. Cannot understand why they keep producing this controller without the modification, it is dam serous !!. In the end I added a FET to invert the TTL signal, with a 1K pull-down on the 4 pin connector (PWM to GND) it now works. Thanks for you input.

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