Qt之modbus tcp 客户端主机读写保持寄存器程序

       这个版本是根据Qt官方例程移植过来的。主要是通过Qt上位机实现对modbus从设备的数据读写。这是笔者在做前期开发时用的，由于在调试的过程中，发现该模块有些不稳定，老是在短时间间隔内出现连接不上设备的问题。于是决定弃用，采用了libmodbbus库+Qt的方式，改版之后确实稳定很多，速率也提上去，这个版本子在一般要求的场合是可以使用，由于笔者开发项目对实时性有严格的要求，所以选择了后者。笔者将在后期将配置代码的过程分享出来。

modbusmaster作为客户端几个重要的头文件：

1、#include <QModbusDataUnit>  //数据单元

2、#include <QModbusTcpClient> //客户端

3、#include <QModbusRtuSerialMaster>  //串口

#include "modbusmaster.h"
#include "widget.h"
#include <QStatusBar>
#include"QDebug"
#include<QTextEdit>

ModbusMaster::ModbusMaster(QObject *parent) : QObject(parent)
{

}
bool ModbusMaster::InitModbusTCPMaster(QString IPaddress, int port)   
{
    if(Master)
    {
        Master->disconnectDevice();
        delete Master;
    }
    Master = new QModbusTcpClient(this);
    if(!Master)
    {
        qDebug()<<"Create modbusdevice fail";
        return 0;
    }

    if(Master->state() != QModbusDevice::ConnectedState)
    {
        Master->setConnectionParameter(QModbusDevice::NetworkAddressParameter,IPaddress);
        Master->setConnectionParameter(QModbusDevice::NetworkPortParameter,port);
        Master->connectDevice();
        Master->setTimeout(500);
        Master->setNumberOfRetries(2);

        if (!Master->connectDevice())
        {
            qDebug()<<" Modbus is  not connect";
        }
        else
        {
            qDebug()<<" Modbus is connect";
        }
    }
    else
    {
            Master->disconnectDevice();
            qDebug()<<" Modbus is  not connect";    
    }
        return 1;
}

bool ModbusMaster::connectDevice()
{
    return Master->connectDevice();
}
void ModbusMaster::disconnectDevice()
{
     Master->disconnectDevice();
}
bool ModbusMaster::writeRegisterData(QString str, int startAddress, int num)
{
    QByteArray byte = QByteArray::fromHex(str.toLatin1().data());
    QString hexStr = byte.toHex().data();
    //发送的数据信息
    QModbusDataUnit writeUnit(QModbusDataUnit::HoldingRegister,startAddress,num);
    //得到的寄存器的类型传给table
    QModbusDataUnit::RegisterType table = writeUnit.registerType();

    for(int i = 0;i < writeUnit.valueCount(); i++)
    {
        int j = 2*i;
        QString str = hexStr.mid(j,2);
        bool ok;
        int hex = str.toInt(&ok,16);
        writeUnit.setValue(i,hex);
    }

    //1 代表server  slave  address sendWriteRequest 是向服务器从机设备地址写数据
    if(auto* reply = Master->sendWriteRequest(writeUnit,1))
    {
        if(!reply->isFinished())
        {
            connect(reply,&QModbusReply::finished,this,[this,reply]()
            {
                if(reply->error() == QModbusDevice::ProtocolError)
                {
                    qDebug()<<"write response ProtocolError:"<<reply->errorString();
                    return 0;
                }
                else if(reply->error() != QModbusDevice::NoError)
                {
                    qDebug()<<"write response error:"<<reply->errorString();
                    return 0;
                }
                reply->deleteLater();
            });
        }
        else
        {
            reply->deleteLater();
            return 1;
        }
    }
    else
    {
        qDebug()<<"write error: "<<Master->errorString();
        return 0;
    }
}

void ModbusMaster::readRegisterData(int startAddress,int num,int ServerAddress)
{
    if(!Master)
        return;

    QModbusDataUnit readUnit(QModbusDataUnit::HoldingRegisters,startAddress,num);

    if(auto* reply = Master->sendReadRequest(readUnit,ServerAddress))
    {
        if(!reply->isFinished())
        {
            connect(reply,&QModbusReply::finished,this,&ModbusMaster::readyRead);
            //connect(this,&QModbusReply::finished,this,&MainWindow::readyRead);

        }
        else
        {
            delete reply;
        }

    }
    else
    {
        qDebug()<<Master->errorString();
        //statusBar()->showMessage(tr("Read error: ") + Master->errorString(), 5000);
    }
}

void ModbusMaster::handleDeviceError(QModbusDevice::Error newError)
{
    if(newError == QModbusDevice::NoError || !Master)
        return;
    emit error_signal(Master->errorString());
}

void ModbusMaster::onStateChanged(int state)
{
    if(state == QModbusDevice::UnconnectedState)
        emit stateChanged_signal(0);
    else if(state == QModbusDevice::ConnectedState)
        emit stateChanged_signal(1);
}

QString ModbusMaster::readyRead()
{
    QString entry = "0";
    auto reply = qobject_cast<QModbusReply*>(sender());
    if(reply)
   {

    if(reply->error() == QModbusDevice::NoError)
    {

         const QModbusDataUnit unit = reply->result();
         entry =QString::number(unit.value(1));//返回的数据单元
         //qDebug()<<"bobo"<<entry;
         NowWeight =entry;

    }
    else if(reply->error() == QModbusDevice::ProtocolError)
    {
        qDebug()<<"error protocolError"<<reply->errorString();
    }
    else
    {
        qDebug()<<"bo error:"<<reply->errorString();
    }
    reply->deleteLater();
  }
    return NowWeight;
}
bool ModbusMaster::IsNotModbusMaster()
{
    if(!Master)
        return 0;
}