NOTE: Tags do not apply to Template expressions, instead you use Template Parameters.
The syntax for a search key tag in an expression is similar to that for database items. The only difference is that <Item> is replaced by <Search Key>.
For referencing a database item:
"<Search Key>"
"<Search Key>.<Property>"
"<Search Key>.<Database Aggregate>"
"<Search Key>.<Database Aggregate>.<Property>"
These work in the same way as the Syntax of OPC Property Tags except that the <Search Key> replaces the <Item>.
Example 1:
"100.CurrentState"
This is a reference to the CurrentState property of the point that has 100 as a search key value.
For calling a method:
"<Search Key>.<Method>( <Argument1>, <Argument2> ... )"
"<Search Key>.<Database Aggregate>.<Method>( <Argument1>, <Argument2> ... )"
These work in the same way as the Method Tags except that the <Search Key> replaces the <Item>.
Example 2:
"100.GetForecastCount()" calls the GetForecastCount method of the forecast item that has 100 as its search key.
For referencing a historic tag:
"<Search Key>.<Database Aggregate>;<OPC Historic Algorithm>;<Start Time>;<Interval>"
"<Search Key>;<OPC Historic Algorithm>;<Start_Date>;<Interval>"
These work in the same way as the Syntax of an OPC Historic Tag except that the <Search Key> replaces the <Item>.
Example 3:
"3214.Forecast1;Max;D;1D" is a reference to the maximum value since the start of the current day for the Forecast item that has 3214 as a search key value. The maximum value is calculated from the values stored in the Forecast1 aggregate for the forecast item.
For referencing a historic calculation tag:
"<Search Key>.<Database Aggregate>:<Offset>:<Search Range>:<Maximum Search Range>"
"<Search Key>:<Offset>:<Search Range>:<Maximum Search Range>"
These work in the same way as the syntaxes in Syntax of a Historic Calculation Tag except that the <Search Key> replaces the <Item>.
Example 4:
"1121:-5M:1H:6H" is a reference to a historic calculation tag where 1121 is a search key value for the source point, -5M is the offset, 1H is the search range and 6H is the maximum search range.