Pulse frequency modulation



  • I am currently building a more industrial style 3d printer with a variation of a berd-air part cooling system.

    I am trying to run a linear compressor with an ssr but it only operates at full power. Would be great for a laser cutter but not a .4mm nozzle.

    Because the pump only operates on half the ac wave I have put a full bridge rectifier on the output to convert to 120v dc that allows me to change the value of Q in M950 for the fan output to the frequency of pump pulses I want per second.

    If I manually change the value in the config file I can run the pump anywhere form 1hz to 70hz and it works how I want but I can not find a way to set the output to pfm instead of pwm.

    As of now I have to manually adjust the pump in the config file but I want the slicer to have control over it just like a normal part cooling fan.

    Any help would be greatly appreciated.


  • Moderator

    If I understand you correctly, you could maybe use a post processor to replace the M106 S PWM fan commands with M950 frequency commands. Otherwise this might belong in the firmware wishlist since I don't think what you're exactly asking for exists at the moment.



  • @Phaedrux Thanks I will have to try that. It would mean the slider on my web interface wouldn't work but that doesn't matter as long as the print gcode is handling it.

    I saw a YouTube video on the compressor by AvE and I thought it was perfect for what I needed, only I didn't think of how to control it. 😅https://youtu.be/eEF-owkyI-o

    First part came off the printer today, functional but I have a lot of tuning to do. now I can add post possessing gcode on the to do list as well.


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