Historical OPC alarms and events

By Jeff Gould, AlarmManagement Insider ContributorNUMEROUS COMPANIES are realizing the value of collecting and storing OPC A&E data. Most likely every plant, at one point or another, has reviewed operations to understand what happened in a given situation. There are numerous reasons for seeking a thorough understanding of an event that already occurred – safety, environmental upsets, regulatory compliance, lost production, quality deviation or equipment damage, to name a few. The economic loss and the safety implications are enough justification to be proactive in preventing these issues from occurring again in the future. Many facilities rely on alarm printers, event logs or other forms of data recorders for information to do these reviews. The problem is that understanding and searching these logs is difficult, if they are even available when they are needed.OPC A&E archivers are transforming simple alarm and event logs into valuable data stores. An OPC A&E Archive is different than an OPC DA historian in that it provides a chronological record of information, allowing quick diagnosis of what led up to a specific event, what the cause was, and how was it handled by operational staff. Most process historians store data by tag, whereas alarms and events are stored based on time. Historically many controls people would crowd around trends and printed event logs trying to piece together what just happened. OPC A&E is instrumental in better handling all of these problems.OPC A&E eliminates the connectivity barriers, enabling universal collection of alarms and events from different devices, and providing a sequential log of what happens in a plant. By storing this data in a relational database, a sequence of events may be reviewed to help answer some of these key questions:

• Why trips occur?
• How did we react?
• What can be done to prevent down time in the future?

OPC A&E, PCs, and databases have proven to be much more reliable than printers that run out of paper when needed most, and archaic event logs that roll over after a certain number of events. In both cases, the events that led up to a situation are often lost forever.Storage of this information in a common database also elevates the visibility and access to alarms and events beyond the control room. Besides just showing a raw log of alarms and events, analysis of this information is resulting in a whole new dimension of applications being developed. Alarm counts and frequencies are proving useful in better managing alarms and providing risk management KPIs to management; event timings and correlations with process equipment are identifying valve timing issues and operator actions that are indicative of process-related problems.Finally, one of the most valuable features of OPC A&E is the ability to categorize data based on where it comes from, or in OPC A&E terminology, the “source” of the event. Many sites generate numerous alarms and events. Storage based on where the event occurred is essential to quickly sifting through the information.Matrikon’s OPC A&E Archiver is one application that stores alarms and events, provides statistical analysis on the data, and even integrates a view of process trends with alarm and event data to provide a complete picture of your operations.Just as OPC DA process historians have proven to be invaluable, OPC A&E archivers are quickly being realized as necessary operating assets.

About the Author

Jeff Gouldis the ProcessGuard Product Manager responsible for overseeing the development, marketing, and sales of Matrikon’s Alarm Management product line. He is a computer engineering technologist and his background includes several years of software development management and sales and marketing of software solutions for the process control industry.