Throughout most of the advanced driver documentation, the term ‘outstation’ is used to refer to any device such as a data logger, programmable logic controller (PLC), outstation, or RTU that is used to obtain data from measuring instruments or sensors.
On a TBox RTU an internal variable (register), used to collect data or to control a particular item of equipment, is assigned a Tag. A TBox tag is associated with a single point in Geo SCADA Expert.
The historical values of the TBox tag may be stored on the RTU in tables of two kinds, called Chronologies and Sampling Tables, and these can be retrieved using Geo SCADA Expert.
For efficiency of data retrieval, points may be organised into groups with consecutive Modbus addresses, and these groups are referred to as Blocks (see Using Blocks of Points).