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MODBUS_SET_SLAVE(3)            Libmodbus Manual            MODBUS_SET_SLAVE(3)


NAME

       modbus_set_slave - set slave number in the context


SYNOPSIS

       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

       EINVAL
           The slave number is invalid.


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 3.1.0                   10/06/2013               MODBUS_SET_SLAVE(3)

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