mavsdk-python Param.select_component() returns UNKNOWN for non-autopilot components (e.g. component 51,123,124)

[VamsiTungala]

Summary

Param.select_component() exists in mavsdk-python and is documented, but on my setup it returns ParamError: UNKNOWN when selecting non-autopilot components (for example component 51), even though those components are discovered by mavsdk_server.

This prevents using the MAVSDK Param plugin to upload params to components from a .params file (e.g. CAN/UAVCAN peripherals).

Environment

• MAVSDK server version: v3.15.0 (from logs)
• mavsdk-python: 3.15.3 (pip install)
• OS: Linux (Ubuntu, Python 3.10)

What I’m trying to do

Use the MAVSDK Param plugin with:

• select_component(component_id, ProtocolVersion.V1) or ProtocolVersion.EXT
• set_param_int/float/custom(...)

to upload parameters to components listed in a PX4 .params file (component IDs like 51, 123, 124 - UAVCAN Devices).

Python Script

#!/usr/bin/env python3
import asyncio
from mavsdk import System
from mavsdk.param import ProtocolVersion
import logging
logging.basicConfig(level=logging.DEBUG)
async def wait_for_connection(drone: System):
    async for state in drone.core.connection_state():
        if state.is_connected:
            return
async def main():
    drone = System()
    await drone.connect(system_address="udpin://0.0.0.0:14550")
    await wait_for_connection(drone)
    print("Connected")
    try:
        await drone.param.select_component(51, ProtocolVersion.V1)
        print("Selected component 51 (V1)")
    except Exception as exc:
        print(f"select_component failed: {exc}")
        pass
    await drone.param.set_param_int("CELL_EMPTY_VOLTA", 3600)
    print("Set CELL_EMPTY_VOLTA = 3600 on component 51")

if __name__ == "__main__":
    asyncio.run(main()) 

Terminal Log

DEBUG:asyncio:Using selector: EpollSelector
DEBUG:grpc._cython.cygrpc:[_cygrpc] Loaded running loop: id(loop)=139374995289184
DEBUG:grpc._cython.cygrpc:Using AsyncIOEngine.POLLER as I/O engine
DEBUG:grpc._cython.cygrpc:[_cygrpc] Loaded running loop: id(loop)=139374995289184
DEBUG:mavsdk.async_plugin_manager:Waiting for mavsdk_server to be ready...
INFO:mavsdk_server:MAVSDK version: v3.15.0 (mavsdk_impl.cpp:33)
INFO:mavsdk_server:Waiting to discover system on udpin://0.0.0.0:14550... (connection_initiator.h:20)
INFO:mavsdk_server:New system on: 10.41.1.1:45177 (system ID: 1) (udp_connection.cpp:263)
DEBUG:mavsdk_server:Component Autopilot (component ID: 1) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 192) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Discovered 2 components (system_impl.cpp:616)
INFO:mavsdk_server:System discovered (connection_initiator.h:62)
INFO:mavsdk_server:Server started (grpc_server.cpp:177)
INFO:mavsdk_server:Server set to listen on 0.0.0.0:50051 (grpc_server.cpp:178)
DEBUG:mavsdk_server:MAVLink: critical: Preflight: GPS Speed Accuracy too low (system_impl.cpp:358)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 155) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 236) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Compass 0 uncalibrated (system_impl.cpp:358)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 40) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Compass 1 uncalibrated (system_impl.cpp:358)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 198) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 97) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Companion Computer (component ID: 191) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Press safety button first (system_impl.cpp:358)
DEBUG:mavsdk_server:MAVLink: emergency: Battery 1: over voltage.         (system_impl.cpp:358)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 51) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 60) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 195) added. (system_impl.cpp:496)
DEBUG:mavsdk_server:Component Unsupported component (component ID: 63) added. (system_impl.cpp:496)
DEBUG:mavsdk.async_plugin_manager:Connected to mavsdk_server!
DEBUG:grpc._cython.cygrpc:[_cygrpc] Loaded running loop: id(loop)=139374995289184
Connected
DEBUG:grpc._cython.cygrpc:[_cygrpc] Loaded running loop: id(loop)=139374995289184
select_component failed: UNKNOWN: 'Unknown'; origin: select_component(); params: (51, <ProtocolVersion.V1: 0>)
DEBUG:grpc._cython.cygrpc:[_cygrpc] Loaded running loop: id(loop)=139374995289184
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
WARNING:mavsdk_server:sending again, retries to do: 5  (CELL_EMPTY_VOLTA). (mavlink_parameter_client.cpp:1163)
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
WARNING:mavsdk_server:sending again, retries to do: 4  (CELL_EMPTY_VOLTA). (mavlink_parameter_client.cpp:1163)
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Compass 0 uncalibrated (system_impl.cpp:358)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Compass 1 uncalibrated (system_impl.cpp:358)
DEBUG:mavsdk_server:MAVLink: critical: Preflight Fail: Press safety button first (system_impl.cpp:358)
DEBUG:mavsdk_server:MAVLink: emergency: Battery 1: over voltage.         (system_impl.cpp:358)
WARNING:mavsdk_server:sending again, retries to do: 3  (CELL_EMPTY_VOLTA). (mavlink_parameter_client.cpp:1163)
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
WARNING:mavsdk_server:sending again, retries to do: 2  (CELL_EMPTY_VOLTA). (mavlink_parameter_client.cpp:1163)
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
WARNING:mavsdk_server:sending again, retries to do: 1  (CELL_EMPTY_VOLTA). (mavlink_parameter_client.cpp:1163)
WARNING:mavsdk_server:Got ill-formed param_value message (param_id empty) (mavlink_parameter_client.cpp:661)
ERROR:mavsdk_server:Error: Retrying failed set param timeout: CELL_EMPTY_VOLTA (mavlink_parameter_client.cpp:1183)
Traceback (most recent call last):
  File "minimum_upload.py", line 31, in <module>
    asyncio.run(main())
  File "/usr/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
    return future.result()
  File "minimum_upload.py", line 27, in main
    await drone.param.set_param_int("CELL_EMPTY_VOLTA", 3600)
  File "/home/user/.local/lib/python3.10/site-packages/mavsdk/param.py", line 585, in set_param_int
    raise ParamError(result, "set_param_int()", name, value)
mavsdk.param.ParamError: TIMEOUT: 'Timeout'; origin: set_param_int(); params: ('CELL_EMPTY_VOLTA', 3600)

Having similar error to get parameters of perticular component. get_all_params() is not downloading other component parameters (my case 51,123,124 - UAVCAN Components)

[julianoes]

Does it have the same system ID and component ID 51?

[VamsiTungala]

I dont know exactly where i can find system id for uavcan devices.
but when i checked wireshark i see heartbeat message from 51 component it shows sys id 1.

I dont see any messages for other two UAVCAN devices one is RM3100(123) and other is ARK RTK GPS (124).

UAVCAN STATUS

nsh> uavcan status
Pool allocator status:
    Capacity hard/soft: 500/250 blocks
    Reserved:  42 blocks
    Allocated: 28 blocks

UAVCAN node status:
    Internal failures: 0
    Transfer errors:   7
    RX transfers:      335117
    TX transfers:      63906

CAN1 status:
    HW errors: 0
    IO errors: 0
    RX frames: 141194
    TX frames: 72838
CAN2 status:
    HW errors: 33
    IO errors: 33
    RX frames: 1047536
    TX frames: 72838

ESC outputs:
INFO  [mixer_module] Param prefix: UAVCAN_EC
control latency: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
Channel Configuration:
Channel 0: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 1: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 2: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 3: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 4: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 5: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 6: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Channel 7: func:   0, value: 0, failsafe: 65535, disarmed: 65535, min: 1, max: 8191
Servo outputs:
INFO  [mixer_module] Param prefix: UAVCAN_SV
control latency: 0 events, 0us elapsed, 0.00us avg, min 0us max 0us 0.000us rms
Channel Configuration:
Channel 0: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 1: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 2: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 3: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 4: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 5: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 6: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000
Channel 7: func:   0, value: 500, failsafe: 500, disarmed: 500, min: 0, max: 1000

Sensor 'gnss':
name: uavcan_gnss
channel 0: node id 124 --> instance 0

Sensor 'gnss_relative':
name: uavcan_gnss_relative

Sensor 'mag':
name: uavcan_mag
channel 0: node id 123 --> instance 1
channel 1: node id 124 --> instance 2

Online nodes (Node ID, Health, Mode):
     51 OK         OPERAT    
     123 OK         OPERAT    
     124 OK         OPERAT    

uavcan: cycle time: 2328010 events, 208948918us elapsed, 89.75us avg, min 13us max 24831us 244.067us rms
uavcan: cycle interval: 2328010 events, 1945.58us avg, min 20us max 151294us 1368.995us rms 

[julianoes]

Oh, so this is a parameter of a uavcan component. I don't think that's hooked up yet. It would be nice indeed if it was.

[VamsiTungala]

I remember testing with MAVSDK 2.2, in that i was able to get/set parameters with component ID's.
I will recheck that over this weekend.