Pre-configure fan PWM frequency

  • Hi all,

    I'm apparently facing some kind of mental blockage here... I have the situation that my part cooling fan only works if it is set to 100%. From what I've read so far, that is most likely a PWM frequency issue (can't try that at the moment because I don't want to disturb a long-running print). From, I understand that the PWM frequency is set when turning the fan on. Do i need to run my generated G-Code file from the slicer through a post-processing script to have the F parameter added to each and every M106 command or is there a way to preconfigure the PWM frequency once during system startup?


  • Moderator

    You can configure the PWM frequency in the M106 commands in config.g so they are applied at boot up. No need for slicer changes or post processing.

  • some fans dont like being powered by pwm signals though.
    They either run at full speed or they dont run at all.

  • Moderator

    @vwegert I know that problem. I have to lower the PWM frequency down to 10Hz to get it to run decently. Use

    M106 P0 S0 F10 C"Part Cooling Fan"

    in your config.g as @Phaedrux already mentioned.

    • P0 stands for the fan port 0
    • S0 says leave the fan off at startup of the machine
    • F10 sets the PWM frequency in Hz
    • C"name" assigns a name (optional)

    Adjust these to your requirements.

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