Access Historic Property Tags

You can use the Root Group branch of the OPC Historic Data Bar to access the historic properties of any database item to which the ViewX client and your User Account has access. The name of each historic property is stored in the database as an OPC Historic Tag.

To access an item’s historic properties:

1. Display the OPC Historic Data Bar (see Display an Explorer Bar in ViewX in the Geo SCADA Expert Guide to ViewX and Virtual ViewX Clients).
2. Expand the Root Group branch of the system (database) for which you want to access an OPC Historic Tag.

   The Root Group’s tree structure corresponds to the way in which the database is structured. The tree structure is restricted to those items for which Geo SCADA Expert is configured to store data historically, along with the Groups or Group Instances in which those items are located.

   Example:

   

3. To display an item’s historic data in the form of a ‘standard’ Ad Hoc Trend, either:
   • Double-click on the item’s entry in the OPC Historic Data Bar.

   Or:

   1. Right-click on the item’s entry in the OPC Historic Data Bar.
      A context sensitive menu is displayed.
   2. Select the Display Trend option from the menu.

      An Ad Hoc Trend of the item’s historic data is displayed.

      Example:

      

      For more information on working with Trends, see the Geo SCADA Expert Guide to Trends.

4. To use an OPC historic property elsewhere (for example, on a Mimic), you can either:
   • Drag an OPC historic property onto, for example, a cell in a Data Grid.

     For more information, see Configuring Data Grids. For information on using a Data Grid to perform a calculation on a block of historic data, see Calculate a Value from a Block of Historic Data.
     

   • Use the OPC Historic Data Bar to ascertain the name of the database aggregate that Geo SCADA Expert uses to store an item’s historic data, then enter that name into the required location.

     The name of a historic aggregate might be required, for example, in an expression for a Mimic animation, or for use elsewhere in Geo SCADA Expert. (Typically, you only need to include the name of a historic aggregate if the database item—such as a Forecast—has more than one historic aggregate). For further more information, see the Geo SCADA Expert Guide to Expressions. In particular see Syntax of an OPC Historic Tag.

     The OCP Historic Data Bar includes a separate entry for each historic aggregate, if a database item has more than one historic aggregate.
     
     

     

Geo SCADA Expert supports several types of Trend. The type of Trend that you can display using the OPC Historic Data Bar is a ‘standard’ Ad Hoc Trend (see Pre-Configured Trends and Ad Hoc Trends in the Geo SCADA Expert Guide to Trends).

Other ways of displaying Trends: see Display a Trend in Run Mode.