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Changing PWM Frequency for Servo Rail Output

Posted by Shawn Gao on July 5, 2016 at 3:22pm

Hi Everyone,

I'm trying to set up a quadcopter right now, and realize that I only have 50Hz ESCs. I've probed the outputs when using the standard quadcopter frame with the Pixhawk and found that it outputs 400Hz signals. I can tell that the frequency mismatch is giving me issues when trying to send throttle setpoints to the ESC, so is there a way for me to change the output PWM frequency from 400Hz to 50Hz?

Also, although I realize that multirotors conventionally use 400Hz, I don't have the resources to buy 4 more ESCs, so I'll need to make do with what I have. Can anyone give me some pointers into how I should best change the frequency?

Thanks!

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Replies

  • Troy Gamm April 15, 2017 at 10:24am
    You can look into the RC_SPEED setting in arducopter. I believe this is what you are looking for.
  • Salim March 23, 2017 at 4:24am

    Hi , 

    I have the same problem. have you managed to change the ESC F rate ? 

  • Shawn Gao July 8, 2016 at 4:46pm

    Hi James, thanks for letting me know. I wasn't actually able to find said parameter on QGroundControl using a quad configuration. Is this parameter exclusive to certain standard firmwares, frames, or control stations (eg. Mission Planner)?

  • Global Innovator July 5, 2016 at 4:33pm

    8 ESCs for 8 motors makes sense

    8 x 50Hz = 400Hz

    so your autopilot can control 8 PWM channels in parallel and is clocked at 50Hz

    • Shawn Gao > Global Innovator July 5, 2016 at 4:46pm

      Not sure you understood what I meant. I was referring to the output PWM frequency that drives my ESCs being 400Hz and I want them to be 50Hz.

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