Data retrieved from the RTUs or PLCs is checked on arrival on an event basis for alarm conditions, determined by a single change or a complex evaluation of conditions and values.
The data is written into the real-time memory resident Nexus Telemetry database, along with time stamp and any quality information. Any Prism User Interfaces with an ‘interest’ in this data are updated automatically.
Alarm occurrence is flagged to the operator on the User Interface mimics or by audible annunciation. A list of currently outstanding alarms is maintained including full details of the alarm progress. All alarms are sent to the archive server as a long-term record.
Further processing of RTU/PLC data can also be performed by bespoke application programs and entries in the archive database for later trending and analysis.