1.1.3. Build an Expression through Historian Tags

The Historian section in the Build Expression window provides you with options to create an expression using Historian tags.

The Historian section contains the following boxes and buttons:


Box/Button	Description
Connection	Select an existing Historian connection or add a new Historian connection.
Tag Name	The Historian tag that you want to use to create an expression.
Search	Retrieves and displays records based on the Historian connection established.
Filters	Filters the displayed records based on the following parameters: Tag Name Description Engineering Unit Data Type Interface Name Source Address
Clear Filters	Removes any filters applied to the displayed records. Note: This button is disabled if no filters are applied.
Max record limit	Limits the number of records displayed.

To create an expression using Historian tags:

In the Build Expression window, in the Historian section, select an existing Historian connection from the Connection drop-down list box, or select to add/edit/remove a Historian connection.
Note: To add a computer scope connection you must disable the Project Scope check box.
To add a new connection, select Add, and then enter the required details. For more information on fields, refer Step 7. Set up Historian Connections to Collect Data
After you add a connection, test the connection, and then enter the name of the Historian tag that you want to use to create an expression.
Select Search to display all the records associated with a Historian tag. You can also select Filters to filter the displayed records based on certain parameters.
In the list of displayed records, double-click the record that you want to create the expression with. The record is added to the Expression box.
Select Functions to add functions to the expression.
Note: Historian tags can be configured in the expression only when Historian functions are used.
Select OK.
Result: An expression is created using Historian tags.