Python-can: AttributeError: 'list' object has no attribute 'channel'

Question

I am trying to use bus.send_periodic to send multiple messages with a period of 100ms. However, when I run the code below I get the error: AttributeError: 'list' object has no attribute 'channel' in line 50: task = bus.send_periodic(messages, 0.1)

This doesn't make sense to me as it is written the same way as the example for the source code.

import logging
import time
import can
import cantools

bus = can.interface.Bus(channel='can0', bustype='socketcan', bitrate='500000')
db = cantools.database.load_file('CAN_v2.2.kcd')

def cyclic_multiple_send(bus):

    messages = []

    # LLC_Mode_Control = Voltage feedback
    messages.append(
        can.Message(
            arbitration_id=0x30041,
            data=[8],
            is_extended_id=True,
        )
    )
    # LLC_Voltage_Limits
    LLC_Voltage_Limits_data = db.encode_message('LLC_Voltage_Limits_3', {
        'Input_voltage_min_3': 0, 'Input_voltage_max_3': 750, 'Output_voltage_min_3': 0, 'Output_voltage_max_3': 750
        }
    )
    messages.append(
        can.Message(
            arbitration_id=0x30047,
            data=LLC_Voltage_Limits_data,
            is_extended_id=True,
        )
    )
    #LLC_Current_Limits
    LLC_Current_Limits_data = db.encode_message('LLC_Current_Limits_3', {
        'Output_current_min_3': 0, 'Output_current_max_3': 75
        }
    )    
    messages.append(
        can.Message(
            arbitration_id=0x30048,
            data=LLC_Current_Limits_data,
            is_extended_id=True,
        )
    )

    task = bus.send_periodic(messages, 0.1)
    assert isinstance(task, can.CyclicSendTaskABC)
    time.sleep(100)

if __name__ == "__main__":
    cyclic_multiple_send(bus)

Answer 1

Look at line 6 of your example code.

bus = can.interface.Bus(channel='can0', bustype='socketcan', bitrate='500000')

While reviewing your linked example code I would write it like this.

bus = can.Bus(channel='can0', interface='socketcan', bitrate='500000')

Because you haven't provided a out of the box running example I am not able to test this solution. It is just a guess while comparing your code with the python-can example code.

And another advise for using StackOverflow: Please read How to Ask and How to create a Minimal, Reproducible Example carefully. Next time please provide us a smaller and reproducible example. You have to help us so we can help you.