Duplicate data check

The check defined as Duplicate Data Check ensures that measurement data is not erroneously overwritten in the Measurement system.

This check is performed prior to loading the data into the tables, but only if the following conditions are met:

• New data exists (Val)

• Database Val already exists in the Measurement system database.

• Database Val data is not a user-estimate or a system-estimate.

This check is applied to all appropriate meter and gas quality (GQ) fields.

The following algorithm is used to detect duplicate data. It checks the absolute value of the difference between the old and new values.

Tol <|ValDB – Valnew|

Where:

• ValDB = Measurement value already in database.

• Valnew = New measurement value.

• Tol = Limit tolerance. The calculated difference must be greater than this amount. Otherwise, the two values are considered to be the same. The tolerance is specified in the configDesc (configDesc) table.

If all fields are identical, the row is discarded and the rejected reading count is updated on the Historical Timestamp Override window. If the rows are different, an audit record is made and validation continues.