Qtmodbus之TCP模式写操作
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00. 目录
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 serialport
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
CONFIG += 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 6.0.0
SOURCES += \\
main.cpp \\
widget.cpp
HEADERS += \\
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. 读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;
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = nullptr);
~Widget();
private:
Ui::Widget *ui;
QModbusClient *modbusDevice = nullptr;
private slots:
void onReadReady();
void onModbusStateChanged(int state);
void on_btnConnect_clicked();
void on_btnCoil_clicked();
void on_btnDiscreteInputs_clicked();
void on_btnInputRegisters_clicked();
void on_btnHoldingRegisters_clicked();
void on_btnCoil_2_clicked();
void on_btnHoldingRegisters_2_clicked();
};
#endif // WIDGET_H
widget.cpp文件
#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QModbusTcpClient>
//构造函数
Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
{
ui->setupUi(this);
//1. 创建QModbusDevice对象
modbusDevice = new QModbusTcpClient(this);
//禁用所有的读操作
ui->btnCoil->setEnabled(false);
ui->btnDiscreteInputs->setEnabled(false);
ui->btnHoldingRegisters->setEnabled(false);
ui->btnInputRegisters->setEnabled(false);
//禁用所有的写操作
ui->btnCoil_2->setEnabled(false);
ui->btnHoldingRegisters_2->setEnabled(false);
connect(modbusDevice, &QModbusClient::errorOccurred, [this](QModbusDevice::Error) {
qDebug() << "new Error: " << modbusDevice->errorString();
});
if (nullptr == modbusDevice)
{
qDebug() << "Cannot Create Modbus Client";
}
else
{
connect(modbusDevice, &QModbusClient::stateChanged,
this, &Widget::onModbusStateChanged);
}
}
//析构函数
Widget::~Widget()
{
if (modbusDevice)
{
modbusDevice->disconnectDevice();
}
delete modbusDevice;
delete ui;
}
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reply
reply->deleteLater();
}
void Widget::onModbusStateChanged(int state)
{
//判断Modbus设备连接是否处于连接状态
if (state == QModbusDevice::UnconnectedState)
{
qDebug() << "TCP Client连接到Server 未连接";
ui->btnConnect->setText(tr("连接"));
ui->btnCoil->setEnabled(false);
ui->btnDiscreteInputs->setEnabled(false);
ui->btnHoldingRegisters->setEnabled(false);
ui->btnInputRegisters->setEnabled(false);
ui->btnCoil_2->setEnabled(false);
ui->btnHoldingRegisters_2->setEnabled(false);
}
else if (state == QModbusDevice::ConnectingState)
{
qDebug() << "TCP Client正在连接Server";
}
else if (state == QModbusDevice::ConnectedState)
{
qDebug() << "TCP Client已经连接到Server";
ui->btnConnect->setText(tr("断开连接"));
ui->btnCoil->setEnabled(true);
ui->btnDiscreteInputs->setEnabled(true);
ui->btnHoldingRegisters->setEnabled(true);
ui->btnInputRegisters->setEnabled(true);
ui->btnCoil_2->setEnabled(true);
ui->btnHoldingRegisters_2->setEnabled(true);
}
else if (state == QModbusDevice::ClosingState)
{
qDebug() << "设备已经被关闭";
}
}
//连接按钮槽函数
void Widget::on_btnConnect_clicked()
{
if (!modbusDevice)
{
return;
}
if (modbusDevice->state() != QModbusDevice::ConnectedState)
{
modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, "127.0.0.1");
modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, 10086);
//设置超时时间
modbusDevice->setTimeout(1000); //1秒
//设置失败重试次数
modbusDevice->setNumberOfRetries(3);
//连接到服务端
bool ok = modbusDevice->connectDevice();
if (!ok)
{
qDebug() << "modbusDevice->connectDevice failed";
}
}
else
{
//断开连接
modbusDevice->disconnectDevice();
ui->btnConnect->setText(tr("连接"));
ui->btnCoil->setEnabled(false);
ui->btnDiscreteInputs->setEnabled(false);
ui->btnHoldingRegisters->setEnabled(false);
ui->btnInputRegisters->setEnabled(false);
ui->btnCoil_2->setEnabled(false);
ui->btnHoldingRegisters_2->setEnabled(false);
}
}
//读线圈
void Widget::on_btnCoil_clicked()
{
//QModbusDataUnit::Coils 从地址0开始读取10个线圈值
QModbusDataUnit data(QModbusDataUnit::Coils, 0, 10);
auto 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 immediately
delete reply;
}
}
}
//读离散输入
void Widget::on_btnDiscreteInputs_clicked()
{
//QModbusDataUnit::DiscreteInputs 从地址0开始读取10个离散输入值
QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);
auto 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 immediately
delete reply;
}
}
}
//读输入寄存器
void Widget::on_btnInputRegisters_clicked()
{
//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);
auto 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 immediately
delete reply;
}
}
}
//读保持寄存器
void Widget::on_btnHoldingRegisters_clicked()
{
//从地址0开始读取10个保持寄存器的值
QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);
auto 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 immediately
delete reply;
}
}
}
//写线圈
void Widget::on_btnCoil_2_clicked()
{
//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 immediately
reply->deleteLater();
}
}
else
{
qDebug() << "sendWriteRequest Error: " << reply->errorString();
}
}
//写保持寄存器
void Widget::on_btnHoldingRegisters_2_clicked()
{
}
执行结果
16:02:56: Starting D:\\ProgramData\\Qt\\build-Test1-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\\debug\\Test1.exe ...
TCP Client正在连接Server
TCP Client已经连接到Server
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)
设备已经被关闭
TCP Client连接到Server 未连接
16:03:17: D:\\ProgramData\\Qt\\build-Test1-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\\debug\\Test1.exe exited with code 0
04. 读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;
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = nullptr);
~Widget();
private:
Ui::Widget *ui;
QModbusClient *modbusDevice = nullptr;
private slots:
void onReadReady();
void onModbusStateChanged(int state);
void on_btnConnect_clicked();
void on_btnCoil_clicked();
void on_btnDiscreteInputs_clicked();
void on_btnInputRegisters_clicked();
void on_btnHoldingRegisters_clicked();
void on_btnCoil_2_clicked();
void on_btnHoldingRegisters_2_clicked();
};
#endif // WIDGET_H
widget.cpp文件
//写保持寄存器
void Widget::on_btnHoldingRegisters_2_clicked()
{
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()以上是关于Qtmodbus之TCP模式写操作的主要内容，如果未能解决你的问题，请参考以下文章
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