Display all the traffic going through a Can chanel, App Designer.

Hi,

I'm building an app with Matlab App Designer and i would like to display on a panel (I use a TextAera for now) all the traffic going through a Can chanel.

I did achieve to display the received ones (using receive() and canSignalTimetable()), but I can't manage to do the same with the transmited ones.

Is there a way to do it ? Maybe easier than keeping in memory all the transmited messages and updating a timer while checking errors in the canChannel, knowing that if there's error in transmitted messages, it seems that you can't know wich message wasn't sent successfully...

Answer 1

[Ayush Singh]

Hello Luc

As I can interpret, you want to display all the traffic going through on CAN channel on TextArea in your case.

As far as I know, since the MATLAB CAN interface does not automatically log transmitted messages in the same way it does for received messages, you will need to implement a mechanism to log them manually.

Here is one approach to achieve this:

1. Before sending messages, initialize a structure or table to store information about each transmitted message. This structure should be accessible in the scope where you're sending messages and where you want to display them.

% Example structure for logging messages
app.transmittedMessages = struct('ID', {}, 'Data', {}, 'Timestamp', {});
% Based on the message strucure, modify the above struct according to your needs

2. Every time you transmit a message, add its details to your logging structure or table. You can capture the timestamp at this point as well.

function transmitCANMessage(app, message)
    % Transmit the message
    transmit(app.canChannel, message);
    
    % Log the message details which are actually the message properties
    newEntry.ID = message.ID;
    newEntry.Data = message.Data;
    newEntry.Timestamp = datetime('now');
    app.transmittedMessages(end+1) = newEntry;
    
    % Update your UI here or call another function to do so
    updateUITransmittedMessages(app);
end

3. After logging a transmitted message, update the TextArea to display the latest message or refresh the list of messages.

function updateUITransmittedMessages(app)
    % Convert the structure of messages to a string representation
    % Below is a simple example, you might need to format it more nicely
    messagesString = '';
    for i = 1:length(app.transmittedMessages)
        msg = app.transmittedMessages(i);
        messagesString = sprintf('ID: %d, Data: %s, Timestamp: %s\n', ...
                         msg.ID, mat2str(msg.Data), msg.Timestamp);
        messagesStr = [messagesStr, messagesString]; 
    end
    
    % Update the TextArea with the messages string
    app.TextArea.Value = messagesStr;
end

I think you should be able to see the message content on the TextArea now!

[Luc]

Hello Ayush,

It was very helpfull as it answers the question of doing it simply with a built-in matlab function and how to do it in the case this function doesn't exist with a proper working method.

Thank you very much.