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Data
Tag objects are essentially an I/O (input / output) database which is
presented in a tree structure. This is held in memory, and used to
transfer data to and from the data source.
A tag is a single data point with a value, associated
quality and time / date stamp. Tags are normally created and maintained in sets,
known as ‘Tag Groups’.
The Tags root object contains:
 | Data servers (normally connected to external devices) |
| Tag Groups (normally these are related data items) |
| Tags (individual data points) |
Although data points can be created elsewhere in the system (Alarms,
Database, Event Logger, Recorder Group, Recorder Line), the tag objects
along with associated servers and groups, are the main data sources.
Individual Tag objects may be either:
| an analog value (e.g. 39.5) |
| a status value (e.g. digital on / digital off) |
| a string (e.g. text) |
Each data type has a different tag icon.
Tags can be linked to other objects or data points, which will
update as the data changes. Refer to Object
Interlinking (Tag Links).
Tags can be connected to real-world I/O points in a number of ways. See
Connectivity for the various options available. |
