table of contents
MODBUS_SET_SLAVE(3) | Libmodbus Manual | MODBUS_SET_SLAVE(3) |
NAME¶
modbus_set_slave - set slave number in the contextSYNOPSIS¶
int modbus_set_slave(modbus_t *ctx, int slave);DESCRIPTION¶
The modbus_set_slave() function shall set the slave number in the libmodbus context.The behavior depends of network and the role of the device:
RTU
Define the slave ID of the remote device to talk in
master mode or set the internal slave ID in slave mode. According to the
protocol, a Modbus device must only accept message holing its slave number or
the special broadcast number.
TCP
The slave number is only required in TCP if the message
must reach a device on a serial network. The special value
MODBUS_TCP_SLAVE (0xFF) can be used in TCP mode to restore the default
value.
The broadcast address is MODBUS_BROADCAST_ADDRESS. This special value must be use when you want all Modbus devices of the network receive the request.
RETURN VALUE¶
The modbus_set_slave() function shall return 0 if successful. Otherwise it shall return -1 and set errno to one of the values defined below.ERRORS¶
EINVALThe slave number is invalid.
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
11/30/2016 | libmodbus 3.0.6 |