写一个使用QT读写modbus协议的完整的示例代码

下面是一个使用QT读写Modbus协议的示例代码，包括了连接Modbus设备、读取和写入Modbus寄存器的功能：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSerialPort/QSerialPort>
#include <QtSerialPort/QSerialPortInfo>
#include <QModbusDataUnit>
#include <QModbusTcpClient>
#include <QModbusRtuSerialMaster>
#include <QModbusTcpServer>
#include <QThread>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 初始化Modbus设备连接
    m_modbusDevice = nullptr;
    m_modbusClient = nullptr;
    m_modbusServer = nullptr;
}

MainWindow::~MainWindow()
{
    // 断开Modbus设备连接
    if (m_modbusClient)
        m_modbusClient->disconnectDevice();
    if (m_modbusServer)
        m_modbusServer->disconnect();

    delete ui;
}

void MainWindow::on_pushButton_Connect_clicked()
{
    // 断开之前的Modbus设备连接
    if (m_modbusClient)
        m_modbusClient->disconnectDevice();
    if (m_modbusServer)
        m_modbusServer->disconnect();

    // 初始化Modbus设备连接
    if (ui->radioButton_TCP->isChecked()) {
        // 连接TCP Modbus设备
        m_modbusClient = new QModbusTcpClient(this);
        m_modbusClient->setConnectionParameter(QModbusDevice::NetworkPortParameter, ui->lineEdit_TCP_Port->text().toInt());
        m_modbusClient->setConnectionParameter(QModbusDevice::NetworkAddressParameter, ui->lineEdit_TCP_IP->text());
        m_modbusDevice = m_modbusClient;
    }
    else {
        // 连接串口 Modbus设备
        m_modbusClient = new QModbusRtuSerialMaster(this);
        m_modbusClient->setConnectionParameter(QModbusDevice::SerialPortNameParameter, ui->comboBox_SerialPort->currentText());
        m_modbusClient->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, ui->comboBox_BaudRate->currentText().toInt());
        m_modbusClient->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, ui->comboBox_DataBits->currentText().toInt());
        m_modbusClient->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, ui->comboBox_StopBits->currentText().toInt());
        m_modbusClient->setConnectionParameter(QModbusDevice::SerialParityParameter, ui->comboBox_Parity->currentIndex());
        m_modbusDevice = m_modbusClient;
    }

    // 连接Modbus设备
    if (!m_modbusDevice->connectDevice()) {
        qDebug() << m_modbusDevice->errorString();
        return;
    }

    // 显示连接状态
    ui->label_Connected->setText("Connected");
}

void MainWindow::on_pushButton_Disconnect_clicked()
{
    // 断开Modbus设备连接
    if (m_modbusClient)
        m_modbusClient->disconnectDevice();
    if (m_modbusServer)
        m_modbusServer->disconnect();

    // 显示连接状态
    ui->label_Connected->setText("Disconnected");
}

void MainWindow::on_pushButton_Read_clicked()
{
    // 创建读取寄存器的数据单元
    QModbusDataUnit readUnit(QModbusDataUnit::HoldingRegisters, ui->spinBox_ReadStartAddr->value(), ui->spinBox_ReadCount->value());

    // 读取寄存器
    if (auto *reply = m_modbusDevice->sendReadRequest(readUnit, ui->spinBox_SlaveID->value())) {
        // 等待读取完成
        while (!reply->isFinished()) {
            QThread::usleep(100);
        }

        // 读取完成，显示读取结果
        if (reply->error() == QModbusDevice::NoError) {
            const QModbusDataUnit unit = reply->result();
            for (int i = 0; i < unit.valueCount(); i++)
                qDebug() << "Value[" << i << "]:" << unit.value(i);
        } else {
            qDebug() << "Read Error:" << reply->errorString();
        }

        // 释放Modbus响应
        reply->deleteLater();
    } else {
        qDebug() << "Read Error:" << m_modbusDevice->errorString();
    }
}

void MainWindow::on_pushButton_Write_clicked()
{
    // 创建写入寄存器的数据单元
    QModbusDataUnit writeUnit(QModbusDataUnit::HoldingRegisters, ui->spinBox_WriteStartAddr->value(), ui->spinBox_WriteCount->value());

    // 设置写入寄存器的值
    for (int i = 0; i < ui->spinBox_WriteCount->value(); i++)
        writeUnit.setValue(i, ui->lineEdit_WriteValues->text().split(',')[i].toInt());

    // 写入寄存器
    if (auto *reply = m_modbusDevice->sendWriteRequest(writeUnit, ui->spinBox_SlaveID->value())) {
        // 等待写入完成
        while (!reply->isFinished()) {
            QThread::usleep(100);
        }

        // 写入完成，显示写入结果
        if (reply->error() == QModbusDevice::NoError) {
            qDebug() << "Write Success";
        } else {
            qDebug() << "Write Error:" << reply->errorString();
        }

        // 释放Modbus响应
        reply->deleteLater();
    } else {
        qDebug() << "Write Error:" << m_modbusDevice->errorString();
    }
}

这段代码中，我们使用了QT自带的QModbusTcpClient和QModbusRtuSerialMaster类实现了TCP和串口两种方式的Modbus设备连接，并使用QModbusDataUnit类读取和写入了Modbus寄存器。在实际使用中，需要根据具体的Modbus设备和通信协议进行调整。