With the addition of Tag Extensions in CitectSCADA v7.20, the variable tag can now represent data as a collection of elements, and each of these elements can contain a collection of items.
Each element provides access to a view of the data value for the tag. Each variable tag can be used on its own or by referencing a particular element. The tag and each element have items that can be referenced to access the following information:
.v : The value, which will access the data value of the tag or element.
.vt : The value timestamp, which will access the timestamp of when the value last changed.
.q : The quality, which will access the quality of the value , either GOOD, UNCERTAIN or BAD. The Quality variable can access further detail using the Cicode Quality functions.
.qt : The quality timestamp, which will access the timestamp of when the quality last changed.
.t : The timestamp, which will access the timestamp of when the tag or element was last updated.