/Qt 5.15

QModbusRtuSerialSlave Class

The QModbusRtuSerialSlave class represents a Modbus server that uses a serial port for its communication with the Modbus client. More...

Header: #include <QModbusRtuSerialSlave>
qmake: QT += serialbus
Since: Qt 5.8
Inherits: QModbusServer

This class was introduced in Qt 5.8.

Public Functions

QModbusRtuSerialSlave(QObject *parent = nullptr)
virtual ~QModbusRtuSerialSlave()

Reimplemented Public Functions

virtual bool processesBroadcast() const override

Reimplemented Protected Functions

virtual void close() override
virtual bool open() override
virtual QModbusResponse processRequest(const QModbusPdu &request) override

Detailed Description

Communication via Modbus requires the interaction between a single Modbus client instance and multiple Modbus server. This class provides the Modbus server implementation via a serial port.

Since multiple Modbus server instances can interact with a Modbus client at the same time (using a serial bus), servers are identified by their serverAddress().

Member Function Documentation

QModbusRtuSerialSlave::QModbusRtuSerialSlave(QObject *parent = nullptr)

Constructs a QModbusRtuSerialSlave with the specified parent. The serverAddress preset is 1.

[virtual] QModbusRtuSerialSlave::~QModbusRtuSerialSlave()

Destroys the QModbusRtuSerialSlave instance.

[override virtual protected] void QModbusRtuSerialSlave::close()

Reimplements: QModbusDevice::close().

[override virtual protected] bool QModbusRtuSerialSlave::open()

Reimplements: QModbusDevice::open().

Note: When calling this function, existing buffered data is removed from the serial port.

[override virtual protected] QModbusResponse QModbusRtuSerialSlave::processRequest(const QModbusPdu &request)

Reimplements: QModbusServer::processRequest(const QModbusPdu &request).

Processes the Modbus client request specified by request and returns a Modbus response.

The Modbus function QModbusRequest::EncapsulatedInterfaceTransport with MEI Type 13 (0x0D) CANopen General Reference is filtered out because it is usually Modbus TCP or Modbus serial ASCII only.

A request to the RTU serial slave will be answered with a Modbus exception response with the exception code QModbusExceptionResponse::IllegalFunction.

[override virtual] bool QModbusRtuSerialSlave::processesBroadcast() const

Reimplements: QModbusServer::processesBroadcast() const.

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Licensed under the GNU Free Documentation License, Version 1.3.