Each input or output on an IEC 60870-5 outstation or other controlled device has an Information Object Address (IOA). This address is used to uniquely identify each item on the device and is transmitted in each ASDU that includes information about that particular input or output.
Where an outstation contains more than one Common Address, IEC 60870-5 Logical outstations are used in Geo SCADA Expert to represent each outstation sector or unit that has a separate Common Address. With such a setup, the outstation’s Common Address and the point’s IOA uniquely identify each Information Object.