Clock synchronization check

The Clock Synchronization Check ensures that data loaded from field equipment is appropriately timestamped.

Note: This is performed by the SCADA system and the results are passed to the Measurement system for display.

This check is used to detect field equipment problems such as:

• Your changes to log files in a flow computer, and the flow computer clock changes to January 1, 1900.

• The battery drops below a certain level and the field equipment clocks quit updating.

• Other device clock faults.

This check applies to current time retrieved from field equipment. It is applied prior to loading data into the measurement system. The following algorithm is used to detect erroneous configuration of the device’s clock:

Tol < (( Host + Offset ) – Field) /60)

Where:

• Host = Clock time on the server at Greenwich Mean Time (GMT) (seconds).

• Offset = Difference between GMT and the field equipment’s time zone (seconds).

• Field = Clock time on the field equipment (seconds).

• Tol = Tolerance acceptable for the data (minutes).

If the check returns a false condition, the data is loaded into the Rejected Readings table space where it awaits for your intervention.