Details
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Bug
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Resolution: Done
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P3: Somewhat important
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5.11.0
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None
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Windows
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fb7a0ef5b31cba52a745006bf9dca61101229de8 (qt/qtserialbus/5.12)
Description
The documentation says:
Connects the device to the Modbus network. Returns true on success; otherwise false.
As far as I understand it should return false if it cannot connect the device to modbus. Instead it always returns true even if the device is not available.
Here a complete example to reproduce that behavior:
main.cpp
#include <QApplication> #include <QDebug> #include "modbusclient.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); ModbusClient client; qDebug() << client.open("192.168.1.157", 502); // address of a non-existent device return a.exec(); }
modbusclient.h
#ifndef MODBUSCLIENT_H #define MODBUSCLIENT_H #include <QObject> #include <QModbusClient> class ModbusClient : public QObject { Q_OBJECT public: explicit ModbusClient(QObject *parent = nullptr); bool open(QString host, int port); private: QModbusClient *_modbus; }; #endif // MODBUSCLIENT_H
modbusclient.cpp
#include "modbusclient.h" #include <QModbusTcpClient> #include <QVariant> ModbusClient::ModbusClient(QObject *parent) : QObject(parent) { _modbus = nullptr; } bool ModbusClient::open(QString host, int port) { if (_modbus) { _modbus->disconnectDevice(); delete _modbus; } _modbus = new QModbusTcpClient(this); _modbus->setConnectionParameter(QModbusDevice::NetworkPortParameter, port); _modbus->setConnectionParameter(QModbusDevice::NetworkAddressParameter, host); _modbus->setTimeout(250); _modbus->setNumberOfRetries(1); return _modbus->connectDevice(); }
Here the output:
true