The management of alarms is not just about operator displays! The entire system is involved. In some U.S. power plants, alarm systems designed to warn plant operators of abnormal operating conditions have become overburdened with insignificant alarms. These alarm systems do not provide alarms with proper priorities, and in some cases are not well maintained. An effective alarm management implementation is dynamic. For this reason, alarm best practices and the application of a continuous improvement rationale are central to this important activity. As alarm systems become less effective, they diminish the effectiveness of all automation.
The first step toward an effective alarm management solution is to develop a sound Alarm Management Philosophy. Next, there needs to be a recognized best practice for alarming, and a methodology that provides a framework to execute these best practices and facilitate continuous improvement. Many plants still use the alarm management philosophy developed by the engineering firm when the plant was built.
Control System Architecture has got an very important role in over-all alarm management. The role of the architecture is to swiftly get the data to the operator and just as swiftly respond to the data from the operator. The processor system must allow the operator to respond quickly and appropriately to any changing condition.
Alarms and events are often used interchangeably in our language. To know what to do with them, how to manage them, it is important to understand and distinguish these two different status of the system.
Alarm displays should be more than just a rapid large meaningless list. Instead the alarm notification should be sorted, summarized, prioritized, and displayed according to significance and focused for direct action. Alarm priority is an important tool to manage the Alarm. Alarms can be prioritized based on safety, process conditions, operator actions, control system diagnostics and then other less critical conditions.
Alarm structures / hierarchies and grouping is another important tool to organize the system. Hierarchies should be designed such that navigation through Hierarchies should be logical and in accordance with the plant areas / applications / utilities.
Alarm summaries and views should be such that it is easily and comfortably readable to the operator, and should help operator to find the particular alarm quickly.
Use of “Always-on-top” Screens / Buttons is always a good tool to keep watching and alert the operator. Using a windowing technology, it is possible to create a “master window” that always stays on “top” of all other activities and can never be suppressed. Color coding on such Always-on-top” Screens help to differentiate between the alarm groups.
Today, the observed effectiveness of alarm management and annunciator applications in the industry varies from plant to plant. In some installations, alarms in the DCS are considered nothing more than a nuisance, and are completely ignored. Slogan ‘Safety First’ is good, but n control systems it is worth to say that ‘Alarms First’.
