FILTER_CAN_MESSAGE_BY_ERROR

Filter a list of can messages to only contain error messages Retain only the messages that are errors Params: messages : Stateful Stateful connection with a list of can.Message Returns: Stateful : Stateful object with only the messages with the `message_id`

Python Code

from flojoy import flojoy, Stateful
import can


@flojoy(deps={"python-can": "4.3.1"})
def FILTER_CAN_MESSAGE_BY_ERROR(messages: Stateful) -> Stateful:
    """Filter a list of can messages to only contain error messages

    Retain only the messages that are errors

    Parameters
    ----------
    messages: Stateful
        Stateful connection with a list of can.Message

    Returns
    -------
    Stateful:
        Stateful object with only the messages with the `message_id`
    """

    messages: can.Message = messages.obj

    filtered = list(
        filter(lambda msg: msg.is_error_frame or msg.error_state_indicator, messages)
    )

    return Stateful(obj=filtered)

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Example

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Download this Flojoy App

This application demonstrates how to use multiple CAN blocks to connect to a PEAK-USB device and read messages from it. The PEAK-USB device is a USB-to-CAN interface that enables you to connect a computer to a CAN network. This device is used in this case to capture the messages of a particular sensor by filtering them directly at the kernel level, thus reducing the load on the CPU, and save those messages to a log file locally.

Once the app is done, the generated logs are exported to an S3 bucket to keep a record of the sensor’s data for further analysis.

To replicate this application, you must connect the PEAK-USB to your computer and install the required driver (refer to the PEAK_CONNECT blocks for more information on the necessary driver for your platform). Then, simply specify the PEAK-USB channel in the required blocks, and this Flojoy application will log the messages received by the device!

Detecting channels A valuable block is the PEAK_DETECT_AVAILABLE_DEVICE. This block allows you to display the devices using the PCAN interface that are connected to your computer.