From OpenSCADAWiki
Data acquisition from the TP device
As an example let's examine and create the acquisition for the air cooler device. The background demo database, as PLC and data source, contains the real-time model of the compressor station with six compressors. Data for two devices of air coolers AT101_1 and AT101_2 of the compressor station CM101 are available via the ModBus/TCP protocol on 10502 port (by default, this is port 502 if there is access to open it).