Problem tuning min/max PWM on servos

Hi all,

I’m having a problem translating several inputs to servo PWM outputs the way I want. For one project, there’s RCIN PWM signal which has min/max values of 1000 and 2000 which I want to convert to higher PWM outputs, say 2200 as a maximum. However, I was not able to do so with both RCx_MIN, RCx_MAX and SERVOx_MIN, SERVOx_MAX.
For a second project, I’d like to have one motor to have a higher PWM minimum, as it doesn’t rotate at lower PWMs due to some internal resistance. It’s not a good idea to fix broken motors this way, but I’d still like to be able to do so.

Being able to limit and trim servo outputs feels like basic functionality, but it’s missing for me.

The flight controller I’m using for both projects is SpeedyBee F405 V3.

RCIN values will be configured through the radio calibration. Regardless of output you shouldn’t need to change that.

For the SERVO values, have you done the ESC calibration yet? Then you can set the SPIN_MIN and SPIN_ARM values to get everything going.

Thanks! I did manage to solve the motor issue simply by calibrating the ESC.
What I was looking for is having different MIN MAX when SERVOx function is RCINx. It seems that, for that function, RCIN PWM is passed directly to servos without any adjustment.
I use it for a VTX module that adjusts power based on PWM.

Look up RC Passthrough. I can try to find a link later if you can’t find it.

Set the SERVOx_FUNCTION for the output you want to the RCINx channel you want to control it from.
Ex) This will control Servo Channel 9 from RC Channel 8.
Servo out

You can use Passthru also then Output Chan = Input Chan.

1 Like