SYNOPSIS
modbus_t *modbus_new_rtu(const char *device, int baud, char parity, int data_bit, int stop_bit);
DESCRIPTION
The modbus_new_rtu() function shall allocate and initialize a modbus_t structure to communicate in RTU mode on a serial line.
The device argument specifies the name of the serial port handled by the OS, eg. /dev/ttyS0 or /dev/ttyUSB0. On Windows, it’s necessary to prepend COM name with \\.\ for COM number greater than 9, eg. \\\\.\\COM10. See http://msdn.microsoft.com/en-us/library/aa365247(v=vs.85).aspx for details
The baud argument specifies the baud rate of the communication, eg. 9600, 19200, 57600, 115200, etc.
- The parity argument can have one of the following values
-
-
N for none
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E for even
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O for odd
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The data_bits argument specifies the number of bits of data, the allowed values are 5, 6, 7 and 8.
The stop_bits argument specifies the bits of stop, the allowed values are 1 and 2.
RETURN VALUE
The modbus_new_rtu() function shall return a pointer to a modbus_t structure if successful. Otherwise it shall return NULL and set errno to one of the values defined below.
ERRORS
- EINVAL
-
An invalid argument was given.
EXAMPLE
SEE ALSO
AUTHORS
The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com>