Understand table lookup data references

You can configure an attribute to obtain its value from a PI AF table. You can define the PI AF table entirely in PI AF, or you can link to or import from a data source outside the PI System (such as a Microsoft SQL table).

Important: We do not recommend using Excel files for linked tables. See the KB article: Do not link AF tables to Excel files.

Table lookup

The table lookup data reference is intended to be a simple table lookup. It uses Microsoft's .NET System.Data.DataTable.Select method, and follows the filter expression rules of that method. Note that not all its features are implemented in PI AF. For example, a table lookup data reference does not include functionality such as column functions and parent/child relation referencing.

Note: The table lookup data reference is not optimized to treat data in an external table as a time series and query for it. For optimal performance, such data should be stored in PI tags on a Data Archive.

Table lookup methodology

You begin by creating a table profile in the Library browser, where you establish general settings for the time zone and cache interval for refreshing data, as well as definitions of table columns and connections to data sources outside the PI System if you are linking to or importing external data.

If you are linking to external data sources, consider creating reusable table connection profiles in the Library browser, as described in Create reusable table connections.

Videos

For information on how to create internal tables for table lookup data references, watch this video:

For information on how to configure table lookup data references, watch this video: