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Serial Lines Explained
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MODBUS_RTU_SET_SERIA(3) Libmodbus Manual MODBUS_RTU_SET_SERIA(3) NAME
modbus_rtu_set_serial_mode - set the serial mode SYNOPSIS
int modbus_rtu_set_serial_mode(modbus_t *ctx); DESCRIPTION
The modbus_rtu_set_serial_mode() function shall set the selected serial mode: MODBUS_RTU_RS232 the serial line is set for RS232 communication. RS-232 (Recommended Standard 232) is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports MODBUS_RTU_RS485 the serial line is set for RS485 communication. EIA-485, also known as TIA/EIA-485 or RS-485, is a standard defining the electrical characteristics of drivers and receivers for use in balanced digital multipoint systems. This standard is widely used for communications in industrial automation because it can be used effectively over long distances and in electrically noisy environments. This function is only supported on Linux kernels 2.6.28 onwards. RETURN VALUE
The modbus_set_serial_mode() function shall return 0 if successful. Otherwise it shall return -1 and set errno to one of the values defined below. ERRORS
EINVAL The current libmodbus backend is not RTU. ENOTSUP The function is not supported on your platform. If the call to ioctl() fails, the error code of ioctl will be returned. AUTHORS
The libmodbus documentation was written by Stephane Raimbault <stephane.raimbault@gmail.com[1]> NOTES
1. stephane.raimbault@gmail.com mailto:stephane.raimbault@gmail.com libmodbus 3.0.3 05/26/2012 MODBUS_RTU_SET_SERIA(3)
