Case sensitivity of UOM abbreviations

A PI Asset Framework (AF) client that is older than PI AF 2015 R2 (v2.7.5) cannot connect to a PI System that has been enabled to use case-sensitive UOM abbreviations. This is due to the possibility of UOM abbreviations being misinterpreted: they are often stored in data references, analysis rules, and client application files, such as spreadsheets and older client displays.

Note: You must upgrade to PI AF 2015 R2 or later to use case-sensitive UOMs.

References to UOM abbreviations

When UOM case-sensitivity is enabled in PI AF 2015 R2 or later, any stored reference to a UOM abbreviation requires that the correct case for the abbreviation be used. For example:

• Data references that are configured with UOMs (such as formula data references) must use the correct abbreviation, or else the UOM lookup fails.

• Analysis rules, such as the Convert function, fail if configured with incorrect casing: Convert('x', 'Kg') instead of Convert('x', 'kg').

• Applications or data references that programmatically access the UOM database must use the correct casing.

  Note: The case-sensitivity option does not alert you when incorrect casing is used in the PI System.

UOM names

Unlike abbreviations, UOM names remain case-insensitive in PI AF 2015 R2 or later when UOM case-sensitivity is enabled. However, when you create a UOM abbreviation, it cannot match the name of a different UOM, even if it differs in casing.

For example, the following is valid:

The following is invalid and generates the error message: 'uom1' already exists in Unit of Measure 'UOM1' in Unit-of-Measure Database.