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  1. #1
    Member
    Join Date
    Aug 2021
    Posts
    2

    Wiring Chinese GRBL Board to 80W CO2 PSU

    Hi Guys!

    I am new to the forum and laser engraving in general. I am "in my mind" 95% complete on a custom CO2 laser build.

    Using a Chinese GRBL board, I have managed to configure setting, calibrate axis, align mirrors etc. The board does not have a 5V PWM output per se, the port is advertised as a "Servo" port, but measuring the V output when running a test cut (with laser PSU deactivated!!) the PWM pin puts out 4.8V when power in Lightburn is set to 100%, 2.4V on 50% power and so on, so I am making an assumption that this should work?

    I have managed to test fire and run the laser with a pot and switch, with water protect hot wired. MY NERVES!!!! I will attach the current wiring as reference.

    I would like to install a flow switch, door switch and additional safety/E-Stop switch on the front panel that can be slammed at any moment. I am a bit lost when it comes to the wiring though, and would prefer not to resort to trial and error on this one. I am hoping that someone here can offer some advice.

    Please let me know if more information is needed. I will also attach an image of how I think this should be wired.

    Thanks!
    Attached Thumbnails Attached Thumbnails Current Wiring.jpg   Proposed Wiring.jpg   Recommended Wiring.jpg  

  2. #2
    Registered
    Join Date
    Nov 2008
    Posts
    527

    Re: Wiring Chinese GRBL Board to 80W CO2 PSU

    Can’t see images. I don’t think this site allows new members to post photos
    I have a home built system. Initially went with Mach3 then switched to DSP controller which is the way to go.
    I would get the laser working first. Absolutely need to have water flowing even for test. I would build a simple circuit that drives the PWM signal. Could be a voltage divider or output from an Arduino.
    Plan to drive it under 1 volt then work your way higher. Having a power meter is important. You don’t want to overdrive the tube.
    Then get the controller working not to exceed the voltages from your testing.


    Sent from my iPhone using Tapatalk

  3. #3
    Member
    Join Date
    Aug 2021
    Posts
    2

    Re: Wiring Chinese GRBL Board to 80W CO2 PSU

    Hi Dean, Thanks for the advice.

    I would like to end up with a DSP, but budget dictates that I use the GRBL for now.

    Yes the laser is working when using a potentiometer and switch, and yes I have water flow, installing the flow switch tomorrow for extra level of safety.

  4. #4
    Registered
    Join Date
    Apr 2005
    Posts
    283

    Re: Wiring Chinese GRBL Board to 80W CO2 PSU

    If you need high speeds on X axis, use GRBL port on STM32F103 (aka. BluePill).
    Make no mistake between my personality and my attitude.
    My personality is who I am. My attitude depends on who you are.

  5. #5
    Registered
    Join Date
    Nov 2008
    Posts
    527

    Re: Wiring Chinese GRBL Board to 80W CO2 PSU

    Great, not sure what help you need. Just connect the switches in series. Each switch stops the beam but the machine keeps going.


    Sent from my iPhone using Tapatalk

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