Ports 1-4 of Pixhawk 6C outputing weird PWM

[lectrician1]

I am setting up a hexcopter using the Pixhawk 6C flight controller.

We are trying to get the motors to spin individually from the Motors tab of QGroundControl. Right now we are able to get all motors to spin, however when increasing the dials for individual motors, only motors 5 and 6 respond to individual dial changes - not motors 1-4. We are trying to fix this.

As part of trying to fix this we monitered PWM output of Pixhawk on all of the ports.

When we increase the individual motor sliders for ports 5-6 our PWM changes from this:

to this (the phase grows correctly):

However, when we increase the individual motor sliders for ports 1-4 we see this:

What’s weirder is if we are monitoring the output of port 3 and increase the motor sliders for both 3 and 4 we see this PWM output on the right:

So some weird incremental PWM output is happening for ports 1-4.

Any ideas what might be causing this? This is just the default hexacopter configuration chosen from QGroundControl. We have not changed any other PX4 settings and are not sure what other settings we might have to change. We’re running QGroundControl v4.3.0 and our firmware is relatively up to date (don’t have the number right now).

[farhang]

Hey,

Have you done ESC calibration?

ESC Calibration | PX4 Guide (main)

[lectrician1]

Yes. That didn’t change anything.

[lectrician1]

It looks like my issue is that same as

Pixhawk 6c I/O PWM Failure

I got a Pixhawk 6c mini and 6c series hardware products from the dealer. I conduct many tests but faced with awful and annoying problem. the problem is PWM output inconsistency in IO PWM port. I setup simple quad configuration and calibration as mentioned in the px4 documentation and products guidance. My firmware configuration is px4 the latest stable one 1.13.3. I measured both from oscilloscope and output voltage level from IO PWM out and find all motor 1,2,3, and 4 is different even if I a…

and

PWM signals to ESC

Good afternoon, I am building a quadcopter using pixhawk 6C. Faced a problem with ESC. When controlling only one motor with a propeller installed on it through qgroundcontrol, I open the throttle by 80-100%, incomprehensible motor beats occur and it does not spin up to maximum speed. If I start all the motors at the same time, then there is no beat and the motors spin up to the maximum. Using an oscilloscope, I checked the PWM signals at the output of the autopilot and saw the following picture:…

Neither of these topics have been solved.

I just upgraded my firmware too, recalibrated, and it didn’t solve the issue. This should probably be filed as a bug?

[farhang]

Please go on and open an issue on PX4 Github.

Issues · PX4/PX4-Autopilot