QModbusResponse Class
QModbusResponse is a container class containing the function code and payload that is stored inside a Modbus ADU. More...
Header: | #include <QModbusResponse> |
qmake: | QT += serialbus |
Since: | Qt 5.8 |
Inherited By: |
This class was introduced in Qt 5.8.
Public Functions
QModbusResponse(FunctionCode code, Args... data) | |
QModbusResponse(FunctionCode code, const int &data = QByteArray()) | |
QModbusResponse(const QModbusPdu &pdu) | |
QModbusResponse() |
Static Public Members
int | calculateDataSize(const QModbusResponse &response) |
int | minimumDataSize(const QModbusResponse &response) |
int | registerDataSizeCalculator(FunctionCode fc, int calculator) |
Detailed Description
A typical Modbus response can looks like this:
QModbusResponse response(QModbusResponse::ReadCoils, QByteArray::fromHex("02cd01"));
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 response can be created like this, if the values are known at compile time:
quint8 payloadInBytes = 2, outputHigh = 0xcd, outputLow = 0x01; QModbusResponse response(QModbusResponse::ReadCoils, payloadInBytes, outputHigh, outputLow);
Member Function Documentation
template <typename Args> QModbusResponse::QModbusResponse(FunctionCode code, Args... data)
Constructs a QModbusResponse with function code set to code and payload set to data. The data is converted and stored in big-endian byte order.
Note: Usage is limited quint8
and quint16
only. This is because QDataStream
stream operators will not only append raw data, but also e.g. size, count, etc. for complex types.
QModbusResponse::QModbusResponse(FunctionCode code, const int &data = QByteArray())
Constructs a QModbusResponse with function code set to code and payload set to data. The data is expected to be stored in big-endian byte order already.
QModbusResponse::QModbusResponse(const QModbusPdu &pdu)
Constructs a copy of pdu.
QModbusResponse::QModbusResponse()
Constructs an invalid QModbusResponse.
[static]
int QModbusResponse::calculateDataSize(const QModbusResponse &response)
Calculates the expected data size for response, based on the response's function code and data. Returns the full size of the response's data part; -1
if the size could not be properly calculated.
See also minimumDataSize and registerDataSizeCalculator.
[static]
int QModbusResponse::minimumDataSize(const QModbusResponse &response)
Returns the expected minimum data size for response based on the response's function code; -1
if the function code is not known.
[static]
int QModbusResponse::registerDataSizeCalculator(FunctionCode fc, int calculator)
This function registers a user-defined implementation to calculate the response data size for function code fc. It can be used to extend or override the implementation inside QModbusResponse::calculateDataSize().
The CalcFuncPtr
is a typedef for a pointer to a custom calculator function with the following signature:
int myCalculateDataSize(const QModbusResponse &pdu);