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 |
Inherits: | QModbusPdu |
Public Functions
QModbusRequest() | |
QModbusRequest(const QModbusPdu &pdu) | |
QModbusRequest(QModbusPdu::FunctionCode code, const QByteArray &newData = ...) | |
QModbusRequest(QModbusPdu::FunctionCode code, Args... newData) |
- 11 public functions inherited from QModbusPdu
Additional Inherited Members
- 1 protected function inherited from QModbusPdu
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 known 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 QModbusPdu &pdu)
Default constructs an instance of QModbusRequest.
QModbusRequest::QModbusRequest(QModbusPdu::FunctionCode code, const QByteArray &newData = ...)
Default constructs an instance of QModbusRequest.
QModbusRequest::QModbusRequest(QModbusPdu::FunctionCode code, Args... newData)
Default constructs an instance of QModbusRequest.