Passthrough telemetry ID

Telemetry ID

I have Wren 44 turboprop with XICOY Fadec, I use FC1 (FlightComputer) for FrSky Telemetry.
I have Ardupilot system installed in plane with Passthrough telemetry.
I have problem with telemetry ID - FC1 uses the same ID with Ardupilot (27)
FC1 uses probably the same passthrough telemetry as Ardupilot does.
The conflict makes both telemetry unreliable and erratic. Each telemetry (FC1 or Ardupilot) works without any problems and with any other sensors but together they are unreliable.
Is there any way to change physical telemetry ID for Ardupilot Passthrough telemetry ?

Thank you

Karel Zadrobilek
Czech republic

Hi, nice question :slight_smile:
I actually added parameters to change the extra downlink IDs and uplink IDs but not for the default one :frowning:

Thank you :slight_smile:

I suppose that physical ID must be changed in Ardupilot in passthrough telemetry settings, not?


Yes, if you can build it yourself, lookup the value here

and change it here:

Unfortunatelly I have never built it. I am afraid too complex for me :frowning:

Anyway after changing physical ID, do i need also to change it in Yaapu script? Or it will recognize it by sensor number?

Thank you.


which board and vehicle do you use, I can build a test version for you

I have Durandal, Plane
Thank you in advance.
I think thank physical ID 28 would be ok for me instead of 27.


nope, max id is 27, but I’ll create a parameter for you to change at runtime

Perfect - even better.
I was afraid, that I have reached maximum :slight_smile:
I will let you know.

OK, here you go, this is latest plane with an additional parameter
FRSKY_DNLINK_ID, default value is 27, you need to carefully choose a free physical ID from the below table

frsky id physical id
0x00, // Physical ID 0 - Vario2 (altimeter high precision)
0xA1, // Physical ID 1 - FLVSS Lipo sensor
0x22, // Physical ID 2 - FAS-40S current sensor
0x83, // Physical ID 3 - GPS / altimeter (normal precision)
0xE4, // Physical ID 4 - RPM
0x45, // Physical ID 5 - SP2UART(Host)
0xC6, // Physical ID 6 - SPUART(Remote)
0x67, // Physical ID 7 - Ardupilot/Betaflight EXTRA DOWNLINK
0x48, // Physical ID 8 -
0xE9, // Physical ID 9 -
0x6A, // Physical ID 10 -
0xCB, // Physical ID 11 -
0xAC, // Physical ID 12 -
0x0D, // Physical ID 13 - Ardupilot/Betaflight UPLINK
0x8E, // Physical ID 14 -
0x2F, // Physical ID 15 -
0xD0, // Physical ID 16 -
0x71, // Physical ID 17 -
0xF2, // Physical ID 18 -
0x53, // Physical ID 19 -
0x34, // Physical ID 20 - Ardupilot/Betaflight EXTRA DOWNLINK
0x95, // Physical ID 21 -
0x16, // Physical ID 22 - GAS Suite
0xB7, // Physical ID 23 - IMU ACC (x,y,z)
0x98, // Physical ID 24 -
0x39, // Physical ID 25 - Power Box
0xBA // Physical ID 26 - Temp
0x1B // Physical ID 27 - ArduPilot/Betaflight DEFAULT DOWNLINK

24 seems a good choice so simply set
FRSKY_DNLINK_ID = 24 and reboot, you will need to rediscover your sensors!

I will try and let you know.
So you think, that this ID parameter wil appear in next “regular” builds?

No need to change anything in Yaapu script?


P. S.
FYI : I have examined my sensors to add another to your table:
R8 (Access receiver) has ID 24 for RSSI and RX bat, ID 26 for analog in 2 (A2) and VFR (valid frame rate)
RB30 (redundancy box) has ID 25
Xicoy FC1 (Fadec telemetry unit) has ID 27
Gas suite has ID 22

Can I use any free ID for Passthrough?


Yes you can use any free ID, nothing has to be done in the yaapu script.

I already created a PR to add the parameter to mainstream ardupilot, once you’ve tested it I will discuss the PR with the dev team.

Edit: I bench tested it on a CubeOrange

did this fix your issue?

thank you very much, sorry I was away from home yesterday.

I have now tested all sensors, and indeed, it did solve my problem

I have used ID 21, now I can see normal sensor behavior - for FADEC telemetry and FrSky Passthrough

Before that I have seen lags in sensor readout (visible on Horus telemetry screen - stars on sensor lines), erratic behaviour of telemetry screen and so on.
You can see missed characters on message screen, now it is perfectly OK

If I could help you with testing, please let me know

Thank you again.



Thanks Karel for your feedback!

Hello another question :slight_smile: Is it possible to use Gas Suite sensor for remaining fuel instead of Cells / FC power module?
It would be ok to left cell and batt voltage for FC battery, but instead of current to see flow, and total / remaining fuel and percentage. All values are given by Gas Suite sensor directly…
Or if you can guide me to lines in script I can try it myself.
But then I need 2 versions of script, because I use both electric planes and Combustion engines, which is difficult in one transmitter …
the best way would be to have possibility to define right pane sensors / values by config file …
Thank you

you can display up to 6 OpenTX sensors embedded in the widget, you need to customize a lua file and define the sensors you’d like to see, many users did that with the GAS suite, check the wiki


Hello, thank you
Of course I have seen and tested 6 user selectable sensors :slight_smile: I just wanted to profit from right panel “battery” set of values which are not that useful in combustion engine plane …

I created a right panel that uses a sensor configuration file just like the bottom one


download latest version from the dev branch

create a sensor file with the usual name but add “_right” in the middle, if your model is model001, your sensor file is model001_sensors.lua, the new file for the right panel should be named model001_right_sensors.lua, syntax is the same.

and last report some feedback :slight_smile: