PX4 CAN Receive block can't read the servo status via DroneCan

Hello,

I refered to the below instruction to read a servo status via dronecan

https://www.mathworks.com/help/uav/px4/ref/px4-can-transmit-receive-data.html

For now, I just want to receive raw data to make sure the connection between the host pc and the pixhawk is correct. But I kept getting status of 4, which means connection is good but can't read the massage from the device.

Here is my setup

Hardware: pixhawk 6x

Data input: CAN Massage

sample time: 0.05 is default (I have tried 0.1. since the publish rate is 10hz in the servo setting)

ID type: 29 bit (for dronecan)

CAN Massage ID: 1011 to read status (DLDS from their website: https://legacy.uavcan.org/Specification/7._List_of_standard_data_types/ )

Length: 4 bytes

CAN Port: Can1

Baud rate: 500000

Node ID: 103

Acuator ID: 3

UAVCAN_ENABLE: 0

Anyone has idea on how to recieve can massage via PX4 Can recieve block ?

Answer 1

[Isha]

Hello,

To receive CAN messages from the Pixhawk using the PX4 CAN Receive block in Simulink, first set the PX4 parameter “UAVCAN_ENABLE = 1” and reboot the Pixhawk.

Ensure your CAN wiring (CAN_H, CAN_L, GND) is correct.

In the Simulink CAN Receive block, Use the full message ID calculated as “(Subject_ID << 8) | Node_ID” (for actuator/servo status: 1011 << 8 | 3 = 259075), with a length of 4 bytes and a sample time matching your publish rate.

Verify that your actuator node is powered and publishing messages, and if needed, use a CAN analyzer to confirm bus activity.

If you still cannot receive messages, try configuring the block to receive any message to check general CAN communication, and double-check all parameters and connections.

Further you can refer: https://www.mathworks.com/help/uav/px4/ref/px4cantransmit.html

https://www.mathworks.com/help/uav/px4/ref/px4canreceive.html

Hope this helps.