Equipment Reference Numbers

Equipment Reference Numbers are also often known as ERNs or informally as Tag Numbers.

They are a unique alpha-numeric sequence that identifies a specific asset.

They often follow a strict structure giving some information as to what the asset might be - for example, the PT in the ERN PT105 may mean 'Pressure Transmitter'.

The ARDI documentation avoids using the term 'Tag Number' as it causes some confusion - users could find themselves confused between 'tag' and 'AR marker'.

So the more generic “Equipment Reference Number” or ERN is used throughout the documentation.