QModbusRequest Class
QModbusRequest is a container class containing the function code and payload that is stored inside a Modbus ADU. More...
Header: | #include <QModbusRequest> |
qmake: | QT += serialbus |
Since: | Qt 5.8 |
Public Functions
QModbusRequest() | |
QModbusRequest(const int &pdu) | |
QModbusRequest(int code, const int &newData = ...) | |
QModbusRequest(int code, Args... newData) |
Detailed Description
QModbusRequest is a container class containing the function code and payload that is stored inside a Modbus ADU.
A Modbus request usually consists of a single byte describing the FunctionCode
and N bytes of payload
A typical Modbus request can looks like this:
QModbusRequest request(QModbusRequest::WriteMultipleCoils, QByteArray::fromHex("0013000a02cd01"));
Note: When using the constructor taking the QByteArray
, please make sure to convert the containing data to big-endian byte order before creating the request.
The same request can be created like this, if the values are know at compile time:
quint16 startAddress = 19, numberOfCoils = 10; quint8 payloadInBytes = 2, outputHigh = 0xcd, outputLow = 0x01; QModbusRequest request(QModbusRequest::WriteMultipleCoils, startAddress, numberOfCoils, payloadInBytes, outputHigh, outputLow);
Member Function Documentation
QModbusRequest::QModbusRequest()
Default constructs an instance of QModbusRequest.
QModbusRequest::QModbusRequest(const int &pdu)
Default constructs an instance of QModbusRequest.
QModbusRequest::QModbusRequest(int code, const int &newData = ...)
Default constructs an instance of QModbusRequest.
QModbusRequest::QModbusRequest(int code, Args... newData)
Default constructs an instance of QModbusRequest.