modbus_new_rtu

Function

Specifies the COM port to connect to the slave device to communicate with, sets the baudrate, parity, etc., and initializes it as Modbus/RTU.

Format

ctx = modbus_new_rtu( device , baud , parity , data_bit , stop_bit )

Parameters

device [ VB.NET： String ] [ C, C++： char * ] [ C#： string ] [ Python：ctypes.c_char_p ]

Specify the serial port (COM port) that communicates with the Modbus slave.

When using Number 10 and above in the COM number, please specify in a format such as "\\\\.\\COM10".

Please refer to the following link for details.

baud[ VB.NET： Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_long ]

Specify the baudrate.

parity [ VB.NET： Sbyte ] [ C, C++： char ] [ C#： sbyte ] [ Python： ctypes.c_char ]

Specify the parity as follows.

data_bit[ VB.NET： Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_int ]

Specify the data bit as 5-8.

stop_bit[ VB.NET： Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_int ]

Specify the stop bit as 1-2.

Return values

ctx [ VB.NET： IntPtr ] [ C, C++： modbus_t * ] [ C#： IntPtr ] [ Python： ctypes.POINTER(modbus_t) ]

If the function succeeds, the pointer address of the modbus_t structure is returned.

If the function fails, NULL is returned. The following error is stored in errno.

Remarks

Specifies the COM port to connect to the slave device to communicate, set the baudrate, parity, etc., and initialize it as Modbus/RTU.

Example

This is an example of specifying COM1 port, baudrate 115200bps, no parity, data bit 8 and stop bit 1.

VB.NET	Dim ctx As IntPtr ctx = modbus_new_rtu("COM1", 115200, 'N', 8, 1)
C, C++	modbus_t *ctx; ctx = modbus_new_rtu("COM1", 115200, 'N', 8, 1);
C#	IntPtr ctx; ctx = modbustcp.NewRtu("COM1", 115200, 'N', 8, 1);
Python	ctx = ctypes.POINTER(modbus_t) ctx = modbus_tcp.modbus_new_rtu("COM1", 115200, 'N', 8, 1)