QModbusTcpServer Class

The QModbusTcpServer class represents a Modbus server that uses a TCP server for its communication with the Modbus client. More...

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

• List of all members, including inherited members
• Obsolete members

Public Functions

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

• 10 public functions inherited from QModbusServer
• 7 public functions inherited from QModbusDevice
• 31 public functions inherited from QObject

Static Public Members

const QMetaObject

staticMetaObject

• 9 static public members inherited from QObject

Reimplemented Protected Functions

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

• 4 protected functions inherited from QModbusServer
• 4 protected functions inherited from QModbusDevice
• 9 protected functions inherited from QObject

Additional Inherited Members

• 1 property inherited from QObject
• 1 public slot inherited from QObject
• 1 signal inherited from QModbusServer
• 2 signals inherited from QModbusDevice
• 2 signals inherited from QObject
• 4 protected functions inherited from QModbusServer
• 4 protected functions inherited from QModbusDevice
• 9 protected functions inherited from QObject

Detailed Description

The QModbusTcpServer class represents a Modbus server that uses a TCP server for its communication with the Modbus client.

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

Modbus TCP networks can have multiple servers. Servers are read/written by a client device represented by QModbusTcpClient.

Member Function Documentation

QModbusTcpServer::QModbusTcpServer(QObject *parent = nullptr)

Constructs a QModbusTcpServer with the specified parent. The serverAddress preset is 255.

[virtual] QModbusTcpServer::~QModbusTcpServer()

Destroys the QModbusTcpServer instance.

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

Reimplemented from QModbusDevice::close().

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

Reimplemented from QModbusDevice::open().

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

Reimplemented from QModbusServer::processRequest().

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

The following Modbus function codes are filtered out as they are serial line only according to the Modbus Application Protocol Specification 1.1b:

• QModbusRequest::ReadExceptionStatus
• QModbusRequest::Diagnostics
• QModbusRequest::GetCommEventCounter
• QModbusRequest::GetCommEventLog
• QModbusRequest::ReportServerId

A request to the TCP server will be answered with a Modbus exception response with the exception code QModbusExceptionResponse::IllegalFunction.