【Qt】modbus之串口模式写操作

00. 目录

文章目录

00. 目录
01. 概述
02. 开发环境
03. 写Coils程序示例
04. 写HoldingRegisters程序示例
05. 综合示例
06. 程序下载
07. 附录

01. 概述

Qt中几个常用的串口modbus类

QModbusRtuSerialSlave       //modbus串口通信方式下的服务器类
QModbusRtuSerialMaster      //串口通信方式下的客户端类
QModbusServer               // QModbusServer类接收和处理modbus的请求。
QModbusDataUnit             //存储接收和发送数据的类，数据类型为1bit和16bit
QModbusReply                //客户端访问服务器后得到的回复（如客户端读服务器数据时包含数据信息）

02. 开发环境

Windows系统：Windows10

Qt版本：Qt5.15或者Qt6

Pro配置文件如下

QT       += core gui serialbus serialportgreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsCONFIG += c++11# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += \main.cpp \widget.cppHEADERS += \widget.h# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

03. 写Coils程序示例

widget.h文件

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>//前向声明
class QModbusClient;
class QModbusReply;class Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();private:QModbusClient *modbusDevice = nullptr;private slots:void onReadReady();
};
#endif // WIDGET_H

widget.cpp文件

#include "widget.h"
#include <QModbusRtuSerialMaster>
#include <QModbusDataUnit>
#include <QModbusReply>
#include <QVariant>
#include <QSerialPort>
#include <QDebug>//构造函数
Widget::Widget(QWidget *parent): QWidget(parent)
{//1. 创建QModbusDevice对象modbusDevice = new QModbusRtuSerialMaster;//2. 如果处于连接状态，则断开连接if (modbusDevice->state() == QModbusDevice::ConnectedState){//断开连接设备modbusDevice->disconnectDevice();}//3. 设置串口相关参数//设置串口信息modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));//设置校验 无校验modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);//设置波特率modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);//设置停止位modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);//设置数据位modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);//4. 设置其他信息//设置超时时间modbusDevice->setTimeout(1000); //1秒//设置失败重试次数modbusDevice->setNumberOfRetries(3);//5. 连接到设备bool ok = modbusDevice->connectDevice();if (!ok){qDebug() << "连接到串口失败： " << modbusDevice->errorString();}else{qDebug() << "连接到串口成功";}//6. 发送写请求//从地址0开始写10个保持寄存器的值//QModbusDataUnit writeData(QModbusDataUnit::HoldingRegisters, 0, 10);//从地址0开始写10个线圈的值QModbusDataUnit writeData(QModbusDataUnit::Coils, 0, 10);for (int i = 0; i < writeData.valueCount(); i++){writeData.setValue(i, (i * i) % 2);}qDebug() << "发送的数据为： " << writeData.values();QModbusReply* reply = modbusDevice->sendWriteRequest(writeData, 1);if (reply){if (!reply->isFinished()){//接收响应信息connect(reply, &QModbusReply::finished, this, [this, reply](){if (reply->error() == QModbusDevice::ProtocolError){//接收到的响应信息是协议错误qDebug() << "写入数据错误：" << reply->errorString();}else if (reply->error() != QModbusDevice::NoError){//接收到的响应消息是其它错误qDebug() << "写入数据错误： " << reply->errorString();}else{//接收到的消息没有错误 一般没有必要解析响应消息const QModbusDataUnit data = reply->result();qDebug() << "消息数据个数：" << data.valueCount() << " :" << data.values();}reply->deleteLater();});}else{//发送没有响应数据//broadcast replies return immediatelyreply->deleteLater();}}else{qDebug() << "sendWriteRequest Error: " << reply->errorString();}//7. 发送读取数据请求//从地址0开始读取10个保持寄存器的值//QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);//从地址0开始读取10个离散输入量的值//QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);//QModbusDataUnit::Coils 从地址0开始读取10个线圈值QModbusDataUnit data(QModbusDataUnit::Coils, 0, 10);//QModbusDataUnit::InputRegisters 从地址0开始读取10个输入寄存器的值//QModbusDataUnit data(QModbusDataUnit::InputRegisters, 0, 10);reply = modbusDevice->sendReadRequest(data, 0x1);if (nullptr == reply){qDebug() << "发送请求数据失败: " << modbusDevice->errorString();}else{if (!reply->isFinished()){connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);}else{//broadcast replies return immediatelydelete reply;}}}//析构函数
Widget::~Widget()
{if (modbusDevice){modbusDevice->disconnectDevice();}delete modbusDevice;
}//准备读取数据的槽函数
void Widget::onReadReady()
{auto reply = qobject_cast<QModbusReply*>(sender());if (nullptr == reply){return;}//判断是否出错if (reply->error() == QModbusDevice::NoError){//读取响应数据const QModbusDataUnit responseData = reply->result();qDebug() << "读到数据为：" << responseData.values();}else if (reply->error() == QModbusDevice::ProtocolError){qDebug() << "Read response Protocol error: " << reply->errorString();}else{qDebug() << "Read response Error: " << reply->errorString();}//删除replyreply->deleteLater();
}

执行结果

20:32:27: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
连接到串口成功
发送的数据为：  QVector(0, 1, 0, 1, 0, 1, 0, 1, 0, 1)
消息数据个数： 10  : QVector(0, 1, 0, 1, 0, 1, 0, 1, 0, 1)
读到数据为： QVector(0, 1, 0, 1, 0, 1, 0, 1, 0, 1)
20:34:02: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

04. 写HoldingRegisters程序示例

widget.h文件

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>//前向声明
class QModbusClient;
class QModbusReply;class Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();private:QModbusClient *modbusDevice = nullptr;private slots:void onReadReady();
};
#endif // WIDGET_H

widget.cpp文件

#include "widget.h"
#include <QModbusRtuSerialMaster>
#include <QModbusDataUnit>
#include <QModbusReply>
#include <QVariant>
#include <QSerialPort>
#include <QDebug>//构造函数
Widget::Widget(QWidget *parent): QWidget(parent)
{//1. 创建QModbusDevice对象modbusDevice = new QModbusRtuSerialMaster;//2. 如果处于连接状态，则断开连接if (modbusDevice->state() == QModbusDevice::ConnectedState){//断开连接设备modbusDevice->disconnectDevice();}//3. 设置串口相关参数//设置串口信息modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));//设置校验 无校验modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);//设置波特率modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);//设置停止位modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);//设置数据位modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);//4. 设置其他信息//设置超时时间modbusDevice->setTimeout(1000); //1秒//设置失败重试次数modbusDevice->setNumberOfRetries(3);//5. 连接到设备bool ok = modbusDevice->connectDevice();if (!ok){qDebug() << "连接到串口失败： " << modbusDevice->errorString();}else{qDebug() << "连接到串口成功";}//6. 发送写请求//从地址0开始写10个保持寄存器的值QModbusDataUnit writeData(QModbusDataUnit::HoldingRegisters, 0, 10);for (int i = 0; i < writeData.valueCount(); i++){writeData.setValue(i, i * i);}qDebug() << "发送的数据为： " << writeData.values();QModbusReply* reply = modbusDevice->sendWriteRequest(writeData, 1);if (reply){if (!reply->isFinished()){//接收响应信息connect(reply, &QModbusReply::finished, this, [this, reply](){if (reply->error() == QModbusDevice::ProtocolError){//接收到的响应信息是协议错误qDebug() << "写入数据错误：" << reply->errorString();}else if (reply->error() != QModbusDevice::NoError){//接收到的响应消息是其它错误qDebug() << "写入数据错误： " << reply->errorString();}else{//接收到的消息没有错误 一般没有必要解析响应消息const QModbusDataUnit data = reply->result();qDebug() << "消息数据个数：" << data.valueCount() << " :" << data.values();}reply->deleteLater();});}else{//发送没有响应数据//broadcast replies return immediatelyreply->deleteLater();}}else{qDebug() << "sendWriteRequest Error: " << reply->errorString();}//7. 发送读取数据请求//从地址0开始读取10个保持寄存器的值QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);//从地址0开始读取10个离散输入量的值//QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);//QModbusDataUnit::Coils 从地址0开始读取10个线圈值//QModbusDataUnit data(QModbusDataUnit::Coils, 0, 10);//QModbusDataUnit::InputRegisters 从地址0开始读取10个输入寄存器的值//QModbusDataUnit data(QModbusDataUnit::InputRegisters, 0, 10);reply = modbusDevice->sendReadRequest(data, 0x1);if (nullptr == reply){qDebug() << "发送请求数据失败: " << modbusDevice->errorString();}else{if (!reply->isFinished()){connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);}else{//broadcast replies return immediatelydelete reply;}}}//析构函数
Widget::~Widget()
{if (modbusDevice){modbusDevice->disconnectDevice();}delete modbusDevice;
}//准备读取数据的槽函数
void Widget::onReadReady()
{auto reply = qobject_cast<QModbusReply*>(sender());if (nullptr == reply){return;}//判断是否出错if (reply->error() == QModbusDevice::NoError){//读取响应数据const QModbusDataUnit responseData = reply->result();qDebug() << "读到数据为：" << responseData.values();}else if (reply->error() == QModbusDevice::ProtocolError){qDebug() << "Read response Protocol error: " << reply->errorString();}else{qDebug() << "Read response Error: " << reply->errorString();}//删除replyreply->deleteLater();
}

执行结果

20:23:23: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
连接到串口成功
发送的数据为：  QVector(0, 1, 4, 9, 16, 25, 36, 49, 64, 81)
消息数据个数： 10  : QVector(0, 1, 4, 9, 16, 25, 36, 49, 64, 81)
读到数据为： QVector(0, 1, 4, 9, 16, 25, 36, 49, 64, 81)
20:23:29: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

05. 综合示例

程序界面

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settingdialog.h文件

#ifndef SETTINGDIALOG_H
#define SETTINGDIALOG_H#include <QDialog>
#include <QtSerialPort>namespace Ui {class SettingDialog;
}//串口设置相关类
class SettingDialog : public QDialog
{Q_OBJECTpublic:struct Settings{//串口名QString serialName = "COM3";//校验位int parity = QSerialPort::NoParity;//波特率int baud = QSerialPort::Baud19200;//数据位int dataBits = QSerialPort::Data8;//停止位int stopBits = QSerialPort::OneStop;//响应时间int responseTime = 1000;//重试次数int numberOfRetries = 3;};explicit SettingDialog(QWidget *parent = nullptr);~SettingDialog();//返回参数设置信息Settings  settings() const;private slots:void on_btnApply_clicked();private:Ui::SettingDialog *ui;Settings m_settings;
};#endif // SETTINGDIALOG_H

settingdialog.cpp文件

#include "settingdialog.h"
#include "ui_settingdialog.h"//构造函数
SettingDialog::SettingDialog(QWidget *parent) :QDialog(parent),ui(new Ui::SettingDialog)
{ui->setupUi(this);//设置默认参数信息ui->serialNameLineEdit->setText(tr("COM3"));ui->parityComboBox->setCurrentIndex(0);ui->baudComboBox->setCurrentText(QString::number(m_settings.baud));ui->dataBitComboBox->setCurrentText(QString::number(m_settings.dataBits));ui->stopBitComboBox->setCurrentText(QString::number(m_settings.stopBits));ui->spinBoxTimeOut->setValue(m_settings.responseTime);ui->spinBoxRetry->setValue(m_settings.numberOfRetries);}//析构函数
SettingDialog::~SettingDialog()
{delete ui;
}//返回参数信息
SettingDialog::Settings SettingDialog::settings() const
{return m_settings;
}//引用按钮槽函数
void SettingDialog::on_btnApply_clicked()
{m_settings.serialName = ui->serialNameLineEdit->text();m_settings.parity = ui->parityComboBox->currentText().toInt();m_settings.baud = ui->baudComboBox->currentText().toInt();m_settings.dataBits = ui->dataBitComboBox->currentText().toInt();m_settings.stopBits = ui->stopBitComboBox->currentText().toInt();m_settings.responseTime = ui->spinBoxTimeOut->value();m_settings.numberOfRetries = ui->spinBoxRetry->value();//隐藏参数设置对话框hide();
}

mainwindow.h文件

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include <QModbusDataUnit>
#include "writeregistermodel.h"QT_BEGIN_NAMESPACEnamespace Ui
{class MainWindow;
}class SettingDialog;
class QModbusClient;
class QModbusReply;QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();//信号与槽进行关联void initActions();//读请求数据包封装QModbusDataUnit readRequest() const;//写请求数据包封装QModbusDataUnit writeRequest() const;private slots:void onConnectButtonClicked();void onConnectTypeChanged(int);void onModbusStateChanged(int state);void onReadButtonClicked();void onReadReady();void onWriteButtonClicked();void onReadWriteButtonClicked();void onWriteTableChanged(int);private:Ui::MainWindow *ui = nullptr;SettingDialog *m_settingDialog = nullptr;QModbusClient *modbusDevice = nullptr;QModbusReply *reply = nullptr;WriteRegisterModel *writeModel = nullptr;};
#endif // MAINWINDOW_H

mainwindow.cpp文件

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMessageBox>
#include "settingdialog.h"
#include <QModbusRtuSerialMaster>
#include <QModbusReply>
#include <QStandardItemModel>
#include <QModbusDataUnit>//连接类型枚举变量
enum ModbusConnection {Serial,Tcp
};MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);//创建对象m_settingDialog = new SettingDialog(this);//初始化信号与槽initActions();//创建写模型writeModel = new WriteRegisterModel(this);writeModel->setStartAddress(ui->sbWriteStartAddr->value());writeModel->setNumberOfValues(ui->cbWriteCount->currentText());//MVCui->treeViewWrite->setModel(writeModel);//隐藏第二列ui->treeViewWrite->hideColumn(2);connect(writeModel, &WriteRegisterModel::updateViewport,ui->treeViewWrite->viewport(), QOverload<>::of(&QWidget::update));//默认为串口连接方式ui->cbConnType->setCurrentIndex(0);onConnectTypeChanged(0);auto model = new QStandardItemModel(10, 1, this);for (int i = 0; i < 10; i++){model->setItem(i, new QStandardItem(QStringLiteral("%1").arg(i + 1)));}ui->cbWriteCount->setModel(model);ui->cbWriteCount->setCurrentText("10");connect(ui->cbWriteCount, &QComboBox::currentTextChanged,writeModel, &WriteRegisterModel::setNumberOfValues);auto valueChanged = QOverload<int>::of(&QSpinBox::valueChanged);connect(ui->sbWriteStartAddr, valueChanged, writeModel, &WriteRegisterModel::setStartAddress);connect(ui->sbWriteStartAddr, valueChanged, this, [this, model](int i){int lastIndex = 0;const int curIndex = ui->cbWriteCount->currentIndex();for (int j = 0; j < 10; j++){//设置使能if (j < (10 - i)){lastIndex = j;model->item(j)->setEnabled(true);}else{//设置禁用model->item(j)->setEnabled(false);}}if (curIndex > lastIndex){ui->cbWriteCount->setCurrentIndex(lastIndex);}});
}//析构函数
MainWindow::~MainWindow()
{if (modbusDevice){modbusDevice->disconnectDevice();delete modbusDevice;}delete ui;
}//信号与槽进行关联s
void MainWindow::initActions()
{//使能部分功能ui->actionConnect->setEnabled(true);ui->actionDisconnect->setEnabled(false);ui->actionQuit->setEnabled(true);ui->actionOption->setEnabled(true);//禁用读写操作ui->btnRead->setEnabled(false);ui->btnWrite->setEnabled(false);ui->btnReadWrite->setEnabled(false);//信号与槽关联connect(ui->btnConnect, &QPushButton::clicked,this, &MainWindow::onConnectButtonClicked);connect(ui->actionConnect, &QAction::triggered,this, &MainWindow::onConnectButtonClicked);connect(ui->actionDisconnect, &QAction::triggered,this, &MainWindow::onConnectButtonClicked);//读操作按钮槽函数关联connect(ui->btnRead, &QPushButton::clicked,this, &MainWindow::onReadButtonClicked);connect(ui->btnWrite, &QPushButton::clicked,this, &MainWindow::onWriteButtonClicked);connect(ui->btnReadWrite, &QPushButton::clicked,this, &MainWindow::onReadWriteButtonClicked);connect(ui->cbRegisterType, QOverload<int>::of(&QComboBox::currentIndexChanged),this, &MainWindow::onWriteTableChanged);connect(ui->cbConnType, QOverload<int>::of(&QComboBox::currentIndexChanged),this, &MainWindow::onConnectTypeChanged);//退出菜单connect(ui->actionQuit, &QAction::triggered, this, &MainWindow::close);//显示参数设置对话框connect(ui->actionOption, &QAction::triggered, m_settingDialog, &QDialog::show);connect(ui->actionAbout, &QAction::triggered, [=]() {QMessageBox::aboutQt(this, "About Qt");});
}//构建请求报文
QModbusDataUnit MainWindow::readRequest() const
{//const auto type = static_cast<QModbusDataUnit::RegisterType>(ui->cbRegisterType->currentData().toInt());QModbusDataUnit::RegisterType type = QModbusDataUnit::Invalid;qDebug() << ui->cbRegisterType->currentText();if (ui->cbRegisterType->currentText() == QString("线圈")){type = QModbusDataUnit::Coils;}else if (ui->cbRegisterType->currentText() == QString("离散输入")){type = QModbusDataUnit::DiscreteInputs;}else if (ui->cbRegisterType->currentText() == QString("输入寄存器")){type = QModbusDataUnit::InputRegisters;}else if (ui->cbRegisterType->currentText() == QString("保持寄存器")){type = QModbusDataUnit::HoldingRegisters;}qDebug() << "请求报文类型: " << type;//获取int startAddress = ui->spReadStartAddr->value();Q_ASSERT(startAddress >= 0 && startAddress < 10);quint16 numberOfEntries = ui->cbReadCount->currentText().toUShort();return QModbusDataUnit(type, startAddress, numberOfEntries);
}//写请求数据包封装
QModbusDataUnit MainWindow::writeRequest() const
{QModbusDataUnit::RegisterType type = QModbusDataUnit::Invalid;qDebug() << ui->cbRegisterType->currentText();if (ui->cbRegisterType->currentText() == QString("线圈")){type = QModbusDataUnit::Coils;}else if (ui->cbRegisterType->currentText() == QString("离散输入")){type = QModbusDataUnit::DiscreteInputs;}else if (ui->cbRegisterType->currentText() == QString("输入寄存器")){type = QModbusDataUnit::InputRegisters;}else if (ui->cbRegisterType->currentText() == QString("保持寄存器")){type = QModbusDataUnit::HoldingRegisters;}qDebug() << "请求报文类型: " << type;//获取int startAddress = ui->sbWriteStartAddr->value();Q_ASSERT(startAddress >= 0 && startAddress < 10);quint16 numberOfEntries = ui->cbWriteCount->currentText().toUShort();//qDebug() << "Test: " << startAddress << " " << numberOfEntries;return QModbusDataUnit(type, startAddress, numberOfEntries);
}//连接和断开连接的槽函数
void MainWindow::onConnectButtonClicked()
{if (!modbusDevice){return;}//清空状态栏消息statusBar()->clearMessage();if (modbusDevice->state() != QModbusDevice::ConnectedState){auto type = static_cast<ModbusConnection>(ui->cbConnType->currentIndex());if (type == Serial){//设置串口连接信息modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter,m_settingDialog->settings().serialName);modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter,m_settingDialog->settings().parity);modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter,m_settingDialog->settings().baud);modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter,m_settingDialog->settings().dataBits);modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter,m_settingDialog->settings().stopBits);}else{//TCP连接信息}modbusDevice->setTimeout(m_settingDialog->settings().responseTime);modbusDevice->setNumberOfRetries(m_settingDialog->settings().numberOfRetries);if (!modbusDevice->connectDevice()){statusBar()->showMessage(tr("Connect failed..") + modbusDevice->errorString(), 5000);}else{statusBar()->showMessage(tr("Connect Successfully"), 5000);qDebug() << "连接OK";ui->actionConnect->setEnabled(false);ui->actionDisconnect->setEnabled(true);//使能读写操作ui->btnRead->setEnabled(true);ui->btnWrite->setEnabled(true);ui->btnReadWrite->setEnabled(true);}}else{//断开连接modbusDevice->disconnectDevice();ui->actionConnect->setEnabled(true);ui->actionDisconnect->setDisabled(true);qDebug() << "断开连接成功";//禁用读写操作ui->btnRead->setEnabled(false);ui->btnWrite->setEnabled(false);ui->btnReadWrite->setEnabled(false);}
}//连接类型槽函数 TCP Serial
void MainWindow::onConnectTypeChanged(int index)
{//如果之前存在连接，则断开连接，然后释放内存if(modbusDevice){modbusDevice->disconnectDevice();delete modbusDevice;modbusDevice = nullptr;}auto type = static_cast<ModbusConnection>(index);if (type == Serial){modbusDevice = new QModbusRtuSerialMaster(this);qDebug() << "new QModbusRtuSerialMaster Ok";statusBar()->showMessage("new QModbusRtuSerialMaster Ok", 3000);}else if (type == Tcp){}else{statusBar()->showMessage("连接类型非法", 5000);}connect(modbusDevice, &QModbusClient::errorOccurred, [this](QModbusDevice::Error){statusBar()->showMessage(modbusDevice->errorString(), 5000);});if (!modbusDevice){//分配空间失败ui->btnConnect->setDisabled(true);if (type == Serial){statusBar()->showMessage(tr("创建Modbus Master失败"), 5000);}else{statusBar()->showMessage(tr("创建Modbus Client失败"), 5000);}}else{connect(modbusDevice, &QModbusClient::stateChanged,this, &MainWindow::onModbusStateChanged);}}//Modbus状态改变槽函数
void MainWindow::onModbusStateChanged(int state)
{//判断Modbus设备连接是否处于连接状态bool connected = (state != QModbusDevice::UnconnectedState);ui->actionConnect->setEnabled(!connected);ui->actionDisconnect->setEnabled(connected);if (QModbusDevice::UnconnectedState == state){ui->btnConnect->setText(tr("Connect"));}else{ui->btnConnect->setText(tr("Disconnect"));}
}//读操作槽函数
void MainWindow::onReadButtonClicked()
{if (!modbusDevice){return;}ui->textEditRead->clear();statusBar()->clearMessage();//发送请求报文数据auto *reply = modbusDevice->sendReadRequest(readRequest(), ui->sbServerAddr->value());if (reply){if (!reply->isFinished()){//完毕之后 自动触发槽函数connect(reply, &QModbusReply::finished, this, &MainWindow::onReadReady);}else{//广播消息  不需要返回响应delete reply;}}else{statusBar()->showMessage(tr("Read Error: ") + modbusDevice->errorString(), 5000);}}//读取数据
void MainWindow::onReadReady()
{auto reply = qobject_cast<QModbusReply*>(sender());if (!reply){return;}if (reply->error() == QModbusDevice::NoError){const QModbusDataUnit data = reply->result();for (int i = 0, total = (int)data.valueCount(); i < total; i++){const QString str = tr("Address: %1 Value: %2").arg(data.startAddress() + i).arg(QString::number(data.value(i), data.registerType() <= QModbusDataUnit::Coils ? 10 : 16));ui->textEditRead->append(str);}}else if (reply->error() == QModbusDevice::ProtocolError){statusBar()->showMessage(tr("Read response error: %1 (Modbus exception: 0x%2)").arg(reply->errorString()).arg(reply->rawResult().exceptionCode(), -1, 16), 5000);}else{statusBar()->showMessage(tr("Read response error: %1 (Code: 0x%2)").arg(reply->errorString()).arg(reply->error(), -1, 16), 5000);}//释放内存reply->deleteLater();
}void MainWindow::onWriteButtonClicked()
{if (!modbusDevice){return;}statusBar()->clearMessage();QModbusDataUnit writeData = writeRequest();QModbusDataUnit::RegisterType type = writeData.registerType();//qDebug() << "test: " << writeData.valueCount();for (int i = 0, total = (int)(writeData.valueCount()); i < total; i++){if (type == QModbusDataUnit::Coils){writeData.setValue(i, writeModel->m_coils[i + writeData.startAddress()]);}else{//qDebug() << "test: " << writeModel->m_holdingRegisters[i + writeData.startAddress()];writeData.setValue(i, writeModel->m_holdingRegisters[i + writeData.startAddress()]);}}qDebug() << "写数据内容为：" << writeData.values();//发送请求报文数据auto *reply = modbusDevice->sendWriteRequest(writeData, ui->sbServerAddr->value());if (reply){if (!reply->isFinished()){//完毕之后 自动触发槽函数connect(reply, &QModbusReply::finished, this, [this, reply]{if (reply->error() == QModbusDevice::ProtocolError){statusBar()->showMessage(tr("Write Protocaol response error: %1").arg(reply->errorString()), 5000);}else if (reply->error() != QModbusDevice::NoError){statusBar()->showMessage(tr("Write response error: %1").arg(reply->errorString()), 5000);}else{qDebug() << "写响应的数据: " << reply->result().values();}reply->deleteLater();});}else{//广播消息  不需要返回响应reply->deleteLater();}}else{statusBar()->showMessage(tr("Write Error: ") + modbusDevice->errorString(), 5000);}
}//读写按钮槽函数
void MainWindow::onReadWriteButtonClicked()
{if (!modbusDevice){return;}statusBar()->clearMessage();QModbusDataUnit writeData = writeRequest();QModbusDataUnit::RegisterType type = writeData.registerType();//qDebug() << "test: " << writeData.valueCount();for (int i = 0, total = (int)(writeData.valueCount()); i < total; i++){if (type == QModbusDataUnit::Coils){writeData.setValue(i, writeModel->m_coils[i + writeData.startAddress()]);}else{//qDebug() << "test: " << writeModel->m_holdingRegisters[i + writeData.startAddress()];writeData.setValue(i, writeModel->m_holdingRegisters[i + writeData.startAddress()]);}}qDebug() << "写数据内容为：" << writeData.values();//发送请求报文数据auto *reply = modbusDevice->sendReadWriteRequest(readRequest(), writeData, ui->sbServerAddr->value());if (reply){if (!reply->isFinished()){connect(reply, &QModbusReply::finished, this, &MainWindow::onReadReady);//完毕之后 自动触发槽函数connect(reply, &QModbusReply::finished, this, [this, reply]{if (reply->error() == QModbusDevice::ProtocolError){statusBar()->showMessage(tr("Write Protocaol response error: %1").arg(reply->errorString()), 5000);}else if (reply->error() != QModbusDevice::NoError){statusBar()->showMessage(tr("Write response error: %1").arg(reply->errorString()), 5000);}else{qDebug() << "写响应的数据: " << reply->result().values();}reply->deleteLater();});}else{//广播消息  不需要返回响应reply->deleteLater();}}else{statusBar()->showMessage(tr("Write Error: ") + modbusDevice->errorString(), 5000);}
}void MainWindow::onWriteTableChanged(int index)
{const bool coilsOrHolding = index == 0 || index == 3;if (coilsOrHolding){ui->treeViewWrite->setColumnHidden(1, index != 0);ui->treeViewWrite->setColumnHidden(2, index != 3);ui->treeViewWrite->resizeColumnToContents(0);}ui->btnReadWrite->setEnabled(index == 3);ui->btnWrite->setEnabled(coilsOrHolding);ui->groupBox_2->setEnabled(coilsOrHolding);
}

writeregistermodel.h文件


#ifndef WRITEREGISTERMODEL_H
#define WRITEREGISTERMODEL_H#include <QAbstractItemModel>
#include <QBitArray>
#include <QObject>class WriteRegisterModel : public QAbstractTableModel
{Q_OBJECTpublic:WriteRegisterModel(QObject *parent = nullptr);int rowCount(const QModelIndex &parent = QModelIndex()) const override;int columnCount(const QModelIndex &parent = QModelIndex()) const override;QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;QVariant headerData(int section, Qt::Orientation orientation, int role) const override;bool setData(const QModelIndex &index, const QVariant &value, int role) override;Qt::ItemFlags flags(const QModelIndex &index) const override;public slots:void setStartAddress(int address);void setNumberOfValues(const QString &number);signals:void updateViewport();public:int m_number = 0;int m_address = 0;QBitArray m_coils;QVector<quint16> m_holdingRegisters;
};#endif // WRITEREGISTERMODEL_H

writeregistermodel.cpp文件

#include "writeregistermodel.h"enum { NumColumn = 0, CoilsColumn = 1, HoldingColumn = 2, ColumnCount = 3, RowCount = 10 };WriteRegisterModel::WriteRegisterModel(QObject *parent): QAbstractTableModel(parent),m_coils(RowCount, false), m_holdingRegisters(RowCount, 0u)
{}int WriteRegisterModel::rowCount(const QModelIndex &/*parent*/) const
{return RowCount;
}int WriteRegisterModel::columnCount(const QModelIndex &/*parent*/) const
{return ColumnCount;
}QVariant WriteRegisterModel::data(const QModelIndex &index, int role) const
{if (!index.isValid() || index.row() >= RowCount || index.column() >= ColumnCount)return QVariant();Q_ASSERT(m_coils.count() == RowCount);Q_ASSERT(m_holdingRegisters.count() == RowCount);if (index.column() == NumColumn && role == Qt::DisplayRole)return QString::number(index.row());if (index.column() == CoilsColumn && role == Qt::CheckStateRole) // coilsreturn m_coils.at(index.row()) ? Qt::Checked : Qt::Unchecked;if (index.column() == HoldingColumn && role == Qt::DisplayRole) // holding registersreturn QString("0x%1").arg(QString::number(m_holdingRegisters.at(index.row()), 16));return QVariant();}QVariant WriteRegisterModel::headerData(int section, Qt::Orientation orientation, int role) const
{if (role != Qt::DisplayRole)return QVariant();if (orientation == Qt::Horizontal) {switch (section) {case NumColumn:return QStringLiteral("#");case CoilsColumn:return QStringLiteral("Coils  ");case HoldingColumn:return QStringLiteral("Holding Registers");default:break;}}return QVariant();
}bool WriteRegisterModel::setData(const QModelIndex &index, const QVariant &value, int role)
{if (!index.isValid() ||  index.row() >= RowCount || index.column() >= ColumnCount)return false;Q_ASSERT(m_coils.count() == RowCount);Q_ASSERT(m_holdingRegisters.count() == RowCount);if (index.column() == CoilsColumn && role == Qt::CheckStateRole) { // coilsauto s = static_cast<Qt::CheckState>(value.toUInt());s == Qt::Checked ? m_coils.setBit(index.row()) : m_coils.clearBit(index.row());emit dataChanged(index, index);return true;}if (index.column() == HoldingColumn && role == Qt::EditRole) { // holding registersbool result = false;quint16 newValue = value.toString().toUShort(&result, 16);if (result)m_holdingRegisters[index.row()] = newValue;emit dataChanged(index, index);return result;}return false;
}Qt::ItemFlags WriteRegisterModel::flags(const QModelIndex &index) const
{if (!index.isValid() || index.row() >= RowCount || index.column() >= ColumnCount)return QAbstractTableModel::flags(index);Qt::ItemFlags flags = QAbstractTableModel::flags(index);if ((index.row() < m_address) || (index.row() >= (m_address + m_number)))flags &= ~Qt::ItemIsEnabled;if (index.column() == CoilsColumn) // coilsreturn flags | Qt::ItemIsUserCheckable;if (index.column() == HoldingColumn) // holding registersreturn flags | Qt::ItemIsEditable;return flags;
}void WriteRegisterModel::setStartAddress(int address)
{m_address = address;emit updateViewport();
}void WriteRegisterModel::setNumberOfValues(const QString &number)
{m_number = number.toInt();emit updateViewport();
}

06. 程序下载

6.1 RTUMaster写操作示例(一).rar
6.2 RTUMasterTest写操作(二).rar

07. 附录

7.1 Qt教程汇总
网址：https://dengjin.blog.csdn.net/article/details/115174639