For SCADAPack controllers using ASCII- or RTU-based Modbus communication, the controller address has to be unique in a set.
For SCADAPack controllers using TCP-based Modbus communication, unique addressing is optional (see Configuring an Advanced Modbus Set in the Geo SCADA Expert Guide to the Advanced Modbus Driver).
Each SCADAPack controller supports both Standard and Extended addressing. Use Extended addressing when more than 255 controllers exist on a channel.
You need to specify the Addressing Mode (Standard or Extended) of each Advanced Modbus Channel that SCADAPack controllers can use to report alarms (see Specify Whether a Channel Uses Unsolicited PLC Functionality in the Geo SCADA Expert Guide to the Advanced Modbus Driver). . You also need to specify the Addressing Mode on each SCADAPack Outstation Form (see Specify the Address Mode), along with the individual controller Address .