Send multiple Can signals at the same time

PriyankaM96

Hello,

I have been trying to send multiple CAN signals at the same time. When selecting each signal for sending, the signal is repeatedly transmitted till its cycle length and if I have to send more signals along with it, it stays in the queue. I need to run multiple signals at the same time and see their output in GUI.

Is it possible to the above function?

my code for emitting multiple signals is :

        foreach(QString payload_id, payload_send_final) {
            const QByteArray payload = QByteArray::fromHex(payload_id.remove(QLatin1Char(' ')).toLatin1());
            frame = QCanBusFrame(frameId, payload);
            if(m_ui->cycle_check->isChecked())
                emit sendFrame(frame,cycle_len.at(i));
            else
                emit sendFrame(frame,"1");

            i = i + 1;
        }

and writing Can signal is as follows :

    m_frame_list.enqueue(frame);
    send_frame_str = frame.toString();
    QTimer timer;
    int i = 1;

    while (!m_frame_list.isEmpty()) {
        QCanBusFrame m_frame = m_frame_list.dequeue();
        while ( i <= cycle.toInt()) {
            m_canDevice->writeFrame(frame);
            delay(5500);
            i = i+1;
        }
    }

Thank you in advance

nagesh

@PriyankaM96 said in Send multiple Can signals at the same time:

delay(5500);

Do you have threads in the code?
looks like you are blocking the event loop by using the delay(5500)

PriyankaM96

@nagesh Thank you for the sudden reply.

I have not used threads till now, since I am confused with its implementation.

jsulm

@PriyankaM96 Why don't you use QTimer (you even created an instance of it) instead of blocking event loop?

PriyankaM96

@jsulm said in Send multiple Can signals at the same time:

QTimer

The delay function is as follows. It uses Qtimer.

void MainWindow::delay( int millisecondsToWait )
{
    QTime dieTime = QTime::currentTime().addMSecs( millisecondsToWait );
    while( QTime::currentTime() < dieTime )
    {
        QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
    }
}

jsulm

@PriyankaM96 said in Send multiple Can signals at the same time:

It uses Qtimer

Then why do you use local event loop? Simply use timout from QTimer to send the data after given time...

PriyankaM96

Okay. Thank you

But still, I have a problem with sending two signals simultaneously.

nagesh

@PriyankaM96 Problem statement not understood correctly.
At current implementation m_canDevice->writeFrame(frame); is delayed for 5.5sec
significance of 5500msec delay?
These 5.5sec delay will be there for each framewrite...

PriyankaM96

Yes, but each frame write takes that much time to avoid overwrite. As far as I tested.

This is to send signals for a cycle number of times (cycle length is extracted for each signal from DBC file).

I want to send two similar signals and keep it running simulataneously

nagesh

@PriyankaM96 One approach would be as follows

the signal is repeatedly transmitted till its cycle length

signals which are having cycle length to be handled separately using QTimer
In QTimer keep track of number of times to send it & for each timeout emit as if it needs to send 1 frame.
emit sendFrame(frame,"1");

Christian Ehrlicher

Looks like your answers are not good enough, but so has the same answers so the next forum is on the road with the same outcoming I would guess :)

PriyankaM96

@nagesh Yes, This can be one approach. Thanks

Is multithreading good for this problem?

PriyankaM96

@Christian-Ehrlicher Yes, I have been looking for answers in different mediums, and posting in a forum was my last option. But hoping more answers :)

Christian Ehrlicher

We told you what to do - the first and important message is: don't block the event loop and use a QTimer.

PriyankaM96

I am sorry, being a beginner. I have tried doing it for last 2 days and I am not able to find solution. When I put Qtimer, like

    connect(timer, &QTimer::timeout,[=]() {
        m_canDevice->writeFrame(frame);
    });

    timer->setInterval(2000);
    timer->start(5000);

the UI doesnt respond or not able to write the frame.

jsulm

@PriyankaM96 said in Send multiple Can signals at the same time:

the UI doesnt respond

Then you still block the event loop somewhere. Please show all relevant code.

PriyankaM96

@jsulm Sorry for the delay in reply. Had a blocking function from another class. Problem solved.