I want dx8 tx signals to pass through my pixhawk:

a) dx8 output chnl 6 (3 ways switch passing pwm > pass through to pix output rc9 > led lighting controller plugged in
b) dx8 output chnl 7 > ---- > osd is displaying data correctly, but won't change panels. osd is seeing heartbeats.
c) dx8 output chnl 8 > rc11 > control tarot tilt gimbal.

standard parms have been set and "write parms" button pressed for

ch7_opt = do nothing
ch8_opt = do nothing
tilt(pitch) RC input channel 8 (mnt_RC_IN_TILT) = rc8
servo out function (RC09_function) = RCpassthru
servo out function (RC10_function) = RCpassthru
servo out function (RC11_function) = RCpassthru

a) led controller  blinks when first booting up so I know that voltage can flow and it is operational, but isn't getting pwm toggle signals which change the led scenes. The toggling of scenes worked once, but I redid the intial setup and has stopped working. I have set up config tuning / standard params / servo out  function RC9 to RCPassThru.
(chnl6 inputs show 1169, 1510, 1851 > chnl 6 ouput values of 0  )

b) OSD data works fine, but isn't reading the pwm from chnl 6 to toggle the 3 osd panels (chnl7 inputs show 1169, 1510, 1851 > chnl 7 ouput values of 0  )

3) My tarot gimbal controller is broke so I can't test my dx8 knob chnl8 for manual tilt. Should this be a simple pass through?




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  • Developer
    You need to connect the in to the mount code the the out RC CH. Set RC Function for channel 9 to be 7 mount tilt. PassThru way of setting up doesn't work on copter yet, but will,probably be added in newer release
    • So what Gregg said doesn't work?

      How do you switch your Led lights on and off? or any switch for that matter?

      • look at the attached screen prints. It shows the settings for the CAMERA. That is where servo values are "passed through".

        My leds are controlled by a pwm setting which feeds into a lighting controller.

        • I have been trying to get this to work on my pixhawk and cannot get any drive to a servo at all. Even with the stock setting for the Iris with Gimbal tilt on RC9 (I have no gimbal) I cannot get a servo to activate when connected to RC9. (The default uses P3 on a TH9x TX).


          I have tried the setting above (Stock) and still not go. This is not so easy. All I want to do is have a receiver controlled switch turn on and off via -100 - +100 Full settings using the throttle Hold (THR) switch.

          Any help would be appreciated. Thanks

          • I have worked it out. During this week I should be able to find the time to do a mini tutorial on it.

            I will post it on My post

            • Can you let us now how you do it?

    • Developer

      If you are not powering the servo rail with a BEC or an ESC with a BEC, the servo will not move on Pixhawk, or APM2.5/6 (JP1 removed)

      • Actually, I have not every yet supplied a separete power source to the Pixhawk and all of my servos have power when I fly my fixed wing. I still don't understand what everyone is talking about when they say "the Pixhawk does not supply power to the servo rail". I have read this link:


        multiple times and I still don't know what they are talking about. All of my servos are working just fine, and they are the ONLY things that are plugged into the servo rail...

  • I think I'm having the same problem. All I want is for my ch7 switch on my DX8 to trigger a payload release. I'm not even sure how to tell mission planner to pair ch7 on the tx to the RC9 spot that my release servo is plugged into...

    Does anyone have any suggestions? I'm really stumped on this.

    • Theres no need to connect any pass thru channels from rx -> apm -> target. Skip the Apm and run the cable straight from the rx -> target.

      There used to be a bug about pass thru not working for APM. I cant recall if its been fixed but ive always used the direct option of rx channel X -> device etc. Your switch doesnt care which channel its receiving it only wants the signal.

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