Qt 5.12; Qt Serial Port; Qt Serial Port C++ Classes. Qt Serial Port C++ Classes. List of C++ classes that enable access to a serial port. Provides functions to access serial ports. Provides information about existing serial ports. Detailed Description.
Constant Value Description QModbusDevice::SerialPortNameParameter 0 This parameter holds the serial port used for device communication, e.g. QString QModbusDevice::SerialParityParameter 1 This parameter holds the parity checking mode. QSerialPort::Parity QModbusDevice::SerialBaudRateParameter 2 This parameter holds the data baud rate for the communication. QSerialPort::BaudRate QModbusDevice::SerialDataBitsParameter 3 This parameter holds the data bits in a frame.
QSerialPort::DataBits QModbusDevice::SerialStopBitsParameter 4 This parameter holds the number of stop bits in a frame. QSerialPort::StopBits QModbusDevice::NetworkPortParameter 5 This parameter holds the network port.
Int QModbusDevice::NetworkAddressParameter 6 This parameter holds the host address for network communication. QString User options. Constant Value Description QModbusDevice::NoError 0 No errors have occurred.
QModbusDevice::ReadError 1 An error occurred during a read operation. QModbusDevice::WriteError 2 An error occurred during a write operation. QModbusDevice::ConnectionError 3 An error occurred when attempting to open the backend. QModbusDevice::ConfigurationError 4 An error occurred when attempting to set a configuration parameter. QModbusDevice::TimeoutError 5 A timeout occurred during I/O.
An I/O operation did not finish within a given time frame. QModbusDevice::ProtocolError 6 A Modbus specific protocol error occurred.
QModbusDevice::ReplyAbortedError 7 The reply was aborted due to a disconnection of the device. QModbusDevice::UnknownError 8 An unknown error occurred.
Enum QModbusDevice:: State This enum describes all possible device states. Member Function Documentation QModbusDevice:: QModbusDevice(.
parent = nullptr) Constructs a Modbus device with the specified parent. virtual QModbusDevice:: QModbusDevice Destroys the instance pure virtual protected void QModbusDevice:: close This function is responsible for closing the Modbus connection. The implementation must ensure that the instance's is set to. Bool QModbusDevice:: connectDevice Connects the device to the Modbus network.
Returns true on success; otherwise false. This function calls as part of its implementation. QModbusDevice:: connectionParameter( int parameter) const Returns the value associated with the given connection parameter. The returned value can be empty. By default the QModbusDevice is initialized with some common values. The serial port settings are even parity, a baud rate of 19200 bits per second, eight data bits and one stop bit.
The network settings for the host address is set to local host and port to 502. Note: For a serial connection to succeed, the needs to be set to a valid communication port. The information about valid serial ports can be obtained from.
Note: If the device is already connected, the settings are taken into account after reconnecting the device. Void QModbusDevice:: disconnectDevice Disconnects the device. This function calls as part of its implementation. QModbusDevice:: error const Returns the error state of the device. signal void QModbusDevice:: errorOccurred( error) This signal is emitted when an error of the type, error, occurs. QModbusDevice:: errorString const Returns descriptive error text for the device error.
![List of baud rates List of baud rates](/uploads/1/2/5/4/125410452/607458576.png)
![List List](/uploads/1/2/5/4/125410452/338331508.png)
pure virtual protected bool QModbusDevice:: open This function is called by. Subclasses must provide an implementation that returns true on successful Modbus connection or false otherwise. The implementation must ensure that the instance's is set to upon success; otherwise.
Void QModbusDevice:: setConnectionParameter( int parameter, const & value) Sets the value of parameter to value. If the parameter already exists, the previous value is overwritten. A active or running connection is not affected by such parameter changes. See also and.
protected void QModbusDevice:: setError(const & errorText, error) Sets the error state of the device. ModBus device implementations must use this function in case of an error to set the error type and a descriptive errorText. protected void QModbusDevice:: setState( newState) Sets the state of the device to newState. Modbus device implementations must use this function to update the device state. QModbusDevice:: state const Returns the current state of the device. See also and.
signal void QModbusDevice:: stateChanged( state) This signal is emitted every time the state of the device changes. The new state is represented by state. See also and.
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I need to send the so called 'break field' If the goal is to send a 'break', then you've asked an XY question with 'How to change the baudrate in c/c'. You cannot generate a break condition by manipulating the baud rate. You would need a baud rate of less than 32 baud to achieve a quarter-second break.
A break condition can be sent on the serial link by using the TCSBRK command in an. BTW your serial port initialization code does not conform to best programming practices. You should always be testing the return codes from system calls. The elements of the termios structure should not be directly assigned, but rather just the individual bits should be modified. Refer to a guide such as.