qt|Qt Modbus库使用，并作为ROS节点发布话题及程序CMakelist编写 qt|C++

在QT框架下，使用QModbus库实现了客户端程序对埃夫特机器人ER50C10A实时读取当前关节角度、笛卡尔坐标值等参数。
同时作为ROS节点发布到话题/joint_states中。
程序逻辑：启动Modbus -- 连接--发送读取请求 --等待qt返回读取完毕信号触发槽函数读取 --读取并显示
其中，连接与发送请求等各部分需要写到不同的槽函数中，否则会报错modbus未连接。
程序代码：（截取部分）主程序：初始化ROS节点、TOPIC、qt对象

int main(int argc, char *argv[]) { ros::init ( argc, argv, "test_modbus" ); ros::NodeHandle n; ros::Publisher Cmd = n.advertise ("/joint_states", 1024 ); QApplication a(argc, argv); ModbusTcpClient w; w.publisher = &Cmd; w.show(); return a.exec(); }

QModbus相关程序：

ModbusTcpClient::ModbusTcpClient(QWidget *parent) : QMainWindow(parent), ui(new Ui::ModbusTcpClient), m_holdingRegisters(20) { ui->setupUi(this); modbusDevice = new QModbusTcpClient(this); ui->lineEdit->setText(QLatin1Literal("192.168.0.103:502")); connect(modbusDevice, &QModbusClient::errorOccurred, [this](QModbusDevice::Error) {statusBar()->showMessage(modbusDevice->errorString(), 5000); }); connect(modbusDevice, &QModbusClient::stateChanged,this, &ModbusTcpClient::onStateChanged); connect(this, SIGNAL(readonce()),this,SLOT(on_readButton_clicked())); } ModbusTcpClient::~ModbusTcpClient() { if (modbusDevice) modbusDevice->disconnectDevice(); delete modbusDevice; delete ui; } void ModbusTcpClient::on_connectButton_clicked() { emit Scan(); if (!modbusDevice) return; statusBar()->clearMessage(); if (modbusDevice->state() != QModbusDevice::ConnectedState) { const QUrl url = QUrl::fromUserInput(ui->lineEdit->text()); modbusDevice->setConnectionParameter(QModbusDevice::NetworkPortParameter, url.port()); modbusDevice->setConnectionParameter(QModbusDevice::NetworkAddressParameter, url.host()); modbusDevice->setTimeout(1000); modbusDevice->setNumberOfRetries(3); if (!modbusDevice->connectDevice()) { statusBar()->showMessage(tr("Connect failed: ") + modbusDevice->errorString(), 5000); } } else { modbusDevice->disconnectDevice(); } } void ModbusTcpClient::onStateChanged(int state) { if (state == QModbusDevice::UnconnectedState) ui->connectButton->setText(tr("Connect")); else if (state == QModbusDevice::ConnectedState) ui->connectButton->setText(tr("Disconnect")); } void ModbusTcpClient::on_readButton_clicked() { if (!modbusDevice) return; statusBar()->clearMessage(); QModbusDataUnit readUnit(QModbusDataUnit::HoldingRegisters, 12, 12); if (auto *reply = modbusDevice->sendReadRequest(readUnit, 1)) { if (!reply->isFinished()) connect(reply, &QModbusReply::finished, this, &ModbusTcpClient::readReady); else delete reply; // broadcast replies return immediately } else { statusBar()->showMessage(tr("Read error: ") + modbusDevice->errorString(), 5000); } } void ModbusTcpClient::readReady() { std::vector jointPos; jointPos.clear(); auto reply = qobject_cast(sender()); if (!reply) return; if (reply->error() == QModbusDevice::NoError) { const QModbusDataUnit unit = reply->result(); for (uint i = 0; i < unit.valueCount(); i++) { const QString entry = tr("Address: %1, Value: %2").arg(unit.startAddress()) .arg(QString::number(unit.value(i), unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16)); ); } ui->textBrowser->insertPlainText("机器人当前位姿："); for (int q = 0; q < 6; q++) { poses.clear(); QString number1 = QString::number(unit.value(2 * q + 1), unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16); if (number1.length() < 4) { poses.append(QString::number(0)); } poses.append(QString::number(unit.value(2 * q + 1), unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16)); QString number2 = QString::number(unit.value(2 * q), unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16); if (number2.length() < 4) { poses.append(QString::number(0)); } poses.append(QString::number(unit.value(2 * q), unit.registerType() <= QModbusDataUnit::Coils ? 10 : 16)); pose[q] = BytesToFloat(poses); qDebug() << poses; jointPos.push_back(pose[q]/180*3.1415926); ui->textBrowser->insertPlainText(QString::number(pose[q])); ui->textBrowser->insertPlainText(" "); } ui->textBrowser->insertPlainText("\n"); ui->textBrowser->moveCursor(QTextCursor::End); jointState.header.stamp = ros::Time::now(); jointState.name = j_names; jointState.position = jointPos; publisher->publish(jointState); } else if (reply->error() == QModbusDevice::ProtocolError) { statusBar()->showMessage(tr("Read response error: %1 (Mobus 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); } reply->deleteLater(); emit readonce(); } void ModbusTcpClient::Display() { ui->textBrowser->insertPlainText(QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss ")); ui->textBrowser->insertPlainText("机器人当前位姿："); ui->textBrowser->moveCursor(QTextCursor::End); }

CMakeList编写：

cmake_minimum_required(VERSION 2.8.3) project(test_modbus) add_compile_options(-std=c++11)set(CMAKE_INCLUDE_CURRENT_DIR ON) set(CMAKE_AUTOMOC ON) set(CMAKE_AUTOUIC ON) set(CMAKE_AUTORCC ON) set(Qt5SerialBus_DIR "/home/xxx/Qt5.8.0/5.8/gcc_64/lib/cmake/Qt5SerialBus")find_package(catkin REQUIRED roscpp std_msgs sensor_msgs) find_package(Qt5Widgets REQUIRED) find_package(Qt5SerialBus REQUIRED)catkin_package()include_directories(${catkin_INCLUDE_DIRS}) include_directories(${Qt5SerialBus_INCLUDE_DIRS}) add_definitions(${Qt5SerialBus_DEFINITIONS}) qt5_wrap_ui( UIC src/test_modbus.ui)add_executable(testmodbus src/main.cpp src/test_modbus.cpp src/test_modbus.h src/test_modbus.ui) target_link_libraries(testmodbus ${catkin_LIBRARIES} Qt5::Widgets Qt5::SerialBus)

结果 QT界面