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MODBUS_NEW_RTU(3) | Libmodbus Manual | MODBUS_NEW_RTU(3) |
NAME¶
modbus_new_rtu - create a libmodbus context for RTUSYNOPSIS¶
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
•E for even
•O for odd
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¶
EINVALAn invalid argument was given.
EXAMPLE¶
modbus_t *ctx; ctx = modbus_new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1); if (ctx == NULL) { fprintf(stderr, "Unable to create the libmodbus context\n"); return -1; }
SEE ALSO¶
modbus_new_tcp(3) modbus_free(3)AUTHORS¶
The libmodbus documentation was written by Stéphane Raimbault < stephane.raimbault@gmail.com[1]>NOTES¶
- 1.
- stephane.raimbault@gmail.com
mailto:stephane.raimbault@gmail.com
10/18/2014 | libmodbus 3.0.6 |