Qt Documentation

Qt 5.14
Qt Serial Bus
C++ Classes
QModbusRtuSerialMaster

QModbusRtuSerialMaster Class

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

Header:	#include <QModbusRtuSerialMaster>
qmake:	QT += serialbus
Since:	Qt 5.8
Inherits:	QModbusClient

This class was introduced in Qt 5.8.

List of all members, including inherited members

Public Functions

	QModbusRtuSerialMaster(QObject *parent = nullptr)
int	interFrameDelay() const
void	setInterFrameDelay(int microseconds)
void	setTurnaroundDelay(int turnaroundDelay)
int	turnaroundDelay() const

Reimplemented Protected Functions

virtual void	close() override
virtual bool	open() override

Detailed Description

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

Member Function Documentation

QModbusRtuSerialMaster::QModbusRtuSerialMaster(QObject **parent* = nullptr)

Constructs a serial Modbus master with the specified parent.

`[override virtual protected]` void QModbusRtuSerialMaster::close()

Reimplements: QModbusDevice::close().

int QModbusRtuSerialMaster::interFrameDelay() const

Returns the amount of microseconds for the silent interval between two consecutive Modbus messages.

See also setInterFrameDelay().

`[override virtual protected]` bool QModbusRtuSerialMaster::open()

Reimplements: QModbusDevice::open().

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

void QModbusRtuSerialMaster::setInterFrameDelay(int microseconds)

Sets the amount of microseconds for the silent interval between two consecutive Modbus messages. By default, the class implementation will use a pre-calculated value according to the Modbus specification. A active or running connection is not affected by such delay changes.

Note: If microseconds is set to -1 or microseconds is less than the pre-calculated delay then this pre-calculated value is used as frame delay.

See also interFrameDelay().

void QModbusRtuSerialMaster::setTurnaroundDelay(int turnaroundDelay)

Sets the amount of milliseconds for the silent interval between a Modbus broadcast and a consecutive Modbus messages to turnaroundDelay. Typically the turnaround delay is in the range of 100 to 200 milliseconds.

This function was introduced in Qt 5.13.

See also turnaroundDelay().

int QModbusRtuSerialMaster::turnaroundDelay() const

Returns the amount of milliseconds for the silent interval between a Modbus broadcast and a consecutive Modbus messages. The default value is set to 100 milliseconds.