今天用Qt实现一个可以通过modbus对线圈寄存器--读写单个寄存器和多个寄存器，离散寄存器--读单个和多个寄存器，保持寄存器--读写单个寄存器和多个寄存器，输入寄存器--读单个和多个寄存器的功能，大概是这么个效果，ui设计好了
用单例模式设计了一个ModbusMaster的类用于连接从站设备以及对从站设备的读写，防止ui更新和读取数据冲突造成卡顿，用了多线程，今天完成了主站设备和从站设备的连接，明天再完成主站设备对从站设备的读写，整个小程序功能比较单一就不用git管理了
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点击查看代码
#include "ModbusMaster.h"
Q_GLOBAL_STATIC(ModbusMaster, theInstance);
ModbusMaster::ModbusMaster(QObject *parent): QObject(parent), m_isConnect(false), m_modbusCtx(nullptr)
{
}ModbusMaster::~ModbusMaster()
{this->disconnectSlave();if (m_modbusCtx != nullptr) {modbus_free(m_modbusCtx);m_modbusCtx = nullptr;}
}
//获取单例对象
ModbusMaster * ModbusMaster::getInstance()
{return theInstance;
}
//初始化RTU
bool ModbusMaster::initRtu(const QString & portName, int baudRate, char parity, int dataBits, int stopBits)
{QMutexLocker locker(&this->m_mutex);if (this->m_modbusCtx != nullptr){modbus_free(this->m_modbusCtx);this->m_modbusCtx = nullptr;}//创建modbus的RTUthis->m_modbusCtx = modbus_new_rtu(portName.toLocal8Bit().data(), baudRate, parity, dataBits, stopBits);if (this->m_modbusCtx == nullptr){QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("初始化RTU失败"));return false;}modbus_set_response_timeout(this->m_modbusCtx, 3, 0);//设置超时3sQMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("初始化RTU成功"));return true;
}
//连接串口
bool ModbusMaster::connectSlave()
{QMutexLocker locker(&this->m_mutex);if (this->m_modbusCtx == nullptr){QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("未初始化RTU"));return false;}if (this->m_isConnect){qDebug() << "已连接从站，不需要再次连接";return true;}int ret = modbus_connect(this->m_modbusCtx);//串口打开了,没有被占用if (ret == -1){QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("串口打开失败"));return false;}this->m_isConnect = true;return true;
}
//设置从站地址
void ModbusMaster::setSlaveId(int slaveId)
{QMutexLocker locker(&this->m_mutex);if (this->m_modbusCtx != nullptr){modbus_set_slave(this->m_modbusCtx, slaveId);qDebug() << "从站地址为" << slaveId;uint16_t testData[1] = { 0 };// 读地址0的保持寄存器（功能码03），需和从站模拟器配置的地址匹配int readRet = modbus_read_registers(m_modbusCtx, 0, 1, testData);if (readRet == -1){QString errMsg = QString::fromLocal8Bit("串口已打开，但从站（ID=%1）无响应：%2").arg(slaveId).arg(modbus_strerror(errno));QMessageBox::warning(nullptr, QString::fromLocal8Bit("提示"), errMsg);// 串口已打开，需关闭modbus_close(this->m_modbusCtx);this->m_isConnect = false;return;}}else{QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("未初始化RTU"));}
}
//断开连接
void ModbusMaster::disconnectSlave()
{QMutexLocker locker(&this->m_mutex);if ((this->m_modbusCtx == nullptr) && this->m_isConnect){QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"), QString::fromLocal8Bit("初始化失败，无法断开连接"));return;}modbus_close(this->m_modbusCtx);this->m_isConnect = false;QMessageBox::information(nullptr, QString::fromLocal8Bit("提示"),QString::fromLocal8Bit("已断开"));
}