Question

我正在尝试从arduino（使用Qt类QSerialPort）收集实时数据并将其实时绘制到图形（使用QCustomPlot类）。我是使用串行设备的新手，因此我不确定在QSerialPort类中使用哪个函数来收集数据。以下是我目前设置序列的代码：

QSerialPort serial;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    serial.setPortName("com4");
    serial.setBaudRate(QSerialPort::Baud9600);
    serial.setDataBits(QSerialPort::Data8);
    serial.setParity(QSerialPort::NoParity);
    serial.setStopBits(QSerialPort::OneStop);
    serial.setFlowControl(QSerialPort::NoFlowControl);
    serial.open(QIODevice::ReadWrite);

    setupRealtimeDataDemo(ui->customPlot);


}

...这是我的实时老虎机数据代码......

void MainWindow::realtimeDataSlot()
{
  // calculate two new data points:
#if QT_VERSION < QT_VERSION_CHECK(4, 7, 0)
  double key = 0;
#else
  double key = QDateTime::currentDateTime().toMSecsSinceEpoch()/1000.0;
#endif
  static double lastPointKey = 0;
  if (key-lastPointKey > 0.01) // at most add point every 10 ms
  {
    double value0 = qSin(key); //sin(key*1.6+cos(key*1.7)*2)*10 + sin(key*1.2+0.56)*20 + 26;
    double value1 = qCos(key); //sin(key*1.3+cos(key*1.2)*1.2)*7 + sin(key*0.9+0.26)*24 + 26;
    // add data to lines:
    ui->customPlot->graph(0)->addData(key, value0);
    ui->customPlot->graph(1)->addData(key, value1);
    // set data of dots:
    ui->customPlot->graph(2)->clearData();
    ui->customPlot->graph(2)->addData(key, value0);
    ui->customPlot->graph(3)->clearData();
    ui->customPlot->graph(3)->addData(key, value1);
    // remove data of lines that's outside visible range:
    ui->customPlot->graph(0)->removeDataBefore(key-8);
    ui->customPlot->graph(1)->removeDataBefore(key-8);
    // rescale value (vertical) axis to fit the current data:
    ui->customPlot->graph(0)->rescaleValueAxis();
    ui->customPlot->graph(1)->rescaleValueAxis(true);
    lastPointKey = key;
  }
  // make key axis range scroll with the data (at a constant range size of 8):
  ui->customPlot->xAxis->setRange(key+0.25, 8, Qt::AlignRight);
  ui->customPlot->replot();

  // calculate frames per second:
  static double lastFpsKey;
  static int frameCount;
  ++frameCount;
  if (key-lastFpsKey > 2) // average fps over 2 seconds
  {
    ui->statusBar->showMessage(
          QString("%1 FPS, Total Data points: %2")
          .arg(frameCount/(key-lastFpsKey), 0, 'f', 0)
          .arg(ui->customPlot->graph(0)->data()->count()+ui->customPlot->graph(1)->data()->count())
          , 0);
    lastFpsKey = key;
    frameCount = 0;
  }
}

有关如何实时获取数据和/或更好实施的任何帮助将不胜感激。谢谢:)）

Answer 1

您可以将readyRead的{{1}}信号连接到一个插槽，以便在新数据到达时读取数据：

QSerialPort

在connect(serial, SIGNAL(readyRead()), this, SLOT(readData()));中，您可以调用readData将所有可用数据读取到readAll()并将数组传递给另一个函数进行绘图：

QByteArray

Answer 2

我wrote a full demo application显示如何从序列中读取数据。

main.cpp 指定打开有效连接所需的设置，在本例中为 Arduino 设备;
serialportreader.h 实现了负责读取数据并将其打印到控制台的类。

对于某些设备（例如Arduino），在open()成功后调用setDataTerminalReady(true);是必要的。因此，对于那些遇到Terminal Example问题的人，请记住将void MainWindow::openSerialPort()破解为：

void MainWindow::openSerialPort()
{
    SettingsDialog::Settings p = settings->settings();
    serial->setPortName(p.name);
    serial->setBaudRate(p.baudRate);
    serial->setDataBits(p.dataBits);
    serial->setParity(p.parity);
    serial->setStopBits(p.stopBits);
    serial->setFlowControl(p.flowControl);
    if (serial->open(QIODevice::ReadWrite)) {
            console->setEnabled(true);
            console->setLocalEchoEnabled(p.localEchoEnabled);
            ui->actionConnect->setEnabled(false);
            ui->actionDisconnect->setEnabled(true);
            ui->actionConfigure->setEnabled(false);
            ui->statusBar->showMessage(tr("Connected to %1 : %2, %3, %4, %5, %6")
                                       .arg(p.name).arg(p.stringBaudRate).arg(p.stringDataBits)
                                       .arg(p.stringParity).arg(p.stringStopBits).arg(p.stringFlowControl));

            // HACK
            serial->setDataTerminalReady(true);
    } else {
        QMessageBox::critical(this, tr("Error"), serial->errorString());

        ui->statusBar->showMessage(tr("Open error"));
    }
}

如何在Qt Creator中收集外部串行设备的实时数据？

2 个答案: