Servo output not responding to RCIN

I’m afraid this request falls in the “remedial” category. Apologies.

After setting up a MavLink connection to my Alexmos gimbal, I wanted to try using standard PWM connections for tilt, roll and yaw.

I wired AUX1 on my carrier board to the RC_PITCH input on the Alexmos controller board.

I have a “knob” on my transmitter configured to channel 9 - for TILT.

On the Mission Planner Setup/Radio-Calibration page channel 9 shows up properly - and responds properly with changes to the PWM bar indication when I move the “knob” higher and lower.

On the Mission Planner Optional-Hardware/Camera-Gimbal page, the gimbal is set up as “servo” type, and Tilt is assigned to SERVO9 and the Input-Channel is set to RC9.

The PWM signal is acknowledged by the Alexmos Controller on it’s RC-Settings page - indicating close to 1500.

My problem is that when I turn the KNOB on my transmitter, there are no changes to the Servo Output as indicated on the Mission Planner Setup/Servo-Output page - and there’s no change on the Alexmos GUI’s screen indicating RC_TILT.

Turning the knob on my transmitter does show up on the Mission Planner Setup/Radio-Calibration page.

It would appear that I’ve missed a parameter that maps the RC9 input with Servo9.

As info - RC9_OPTION=0 per the doc ArduCopter guidance for having manual control of the gimbal axis.

I’m sorry for asking such a remedial question. Thank you for helping me!

Please save this to a file and load it in mission planner:


If that does not work do:


Check Complete Parameter List — Copter documentation
BRD_SAFETY_MASK - A bitmask which controls what outputs can move while the safety switch has not been pressed

Amilcarlucas -

The answer is SERVO9_FUNCTION,1 – which assigns “RCPassThru”

For reference to others who find this post searching with a similar question - here are some links from the docs:

And this page - which is confusing to me - I can’t tell if its referring to parameters that don’t exist any more:

It seems there’s a parameter called “RCPassThru(n)” - I couldn’t find other references to these parameters. And on the tables - I’m not sure what the column labeled “ID” is referring to.

Maybe someone can take a quick look and see.

Thanks Amilcarlucas!

Thanks Shawn - I checked - only the motors were restricted. RCPassThru was what solved the problem - as per my comment below.

They exist. They are ID values used in the Servo Function to define the source for the pass thru. So SERVO9_FUNCTION set to “1” will pass RCIN9 to SERVO9 out. If it was “51” then it will pass RCIN1 to SERVO9 out.
If we were talking about SERVO10_FUNCTION and it was set to “1” then it would pass RCIN10 to SERVO10 out.

This allows you to configure any input to passthru any output. “1” respects Input/output

Thanks Shawn - a simple mapping. Thanks!