One of the more important tasks in the alarm management lifecycle is auditing of the alarm system configuration. Auditing preserves your investment in rationalization, checks for changes that bypassed the MOC process, and helps you to maintain the integrity of the alarm system. Oh, and it also required per the ISA-18.2 and IEC 62682 alarm management standards.

Alarm rationalization establishes which alarms are enabled, assigns their priority and classification, determines the appropriate alarm limit, as well as documents the rationale for the alarm (cause, consequence, corrective action, time to respond). The rationalization information is documented in a master alarm database (MADB), which is the “authorized list of rationalized alarms and associated attributes”.  An effective auditing tool automatically and systematically compares the values of alarm attributes (e.g., limit, priority, enable / disable status) in the MADB vs. the actual values in the running control system. 

One of the “best-kept secrets” in the DeltaV system is the built-in alarm system auditing functionality that was introduced in V13.3, and which is available at no extra charge. 

From the DeltaV System Alarm Management (SAM) tool, two types of audit reports can be defined, scheduled, and executed as a background task with minimal impact on CPU resources and without the need for OPC connectivity. The audit reports can be reviewed as-is, making for a simple and effective audit, or they can be used for comparison against an external master alarm database (such as exida’s SILAlarm). They can be loaded into SILAlarm, on-demand or automatically via a scheduler, to display the differences for review, resolution, and enforcement (as necessary) in the Audit Viewer tool.

The DeltaV Runtime Audit report snapshots the current values of selected alarm attributes in the DeltaV Controller (Runtime DB), while the Differences report flags discrepancies between the DeltaV Controller (Runtime DB) and the DeltaV Engineering Workstation (Configuration DB). The DeltaV Audit reports provide a comparison benchmark for the most commonly used alarm parameters (priority, enable / disable, limit). This is similar to what one might set up using a third party tool for auditing & enforcement; it won’t evaluate all alarm attributes because of the impact on network communication and because of the OPC licensing cost to read each attribute for each alarm (> 10 attributes / alarm).

DeltaV Alarm Audit Reports are defined from within DeltaV’s System Alarm Management tool. Reports can be scheduled to run automatically or on demand and are output in both xml and html formats. The scope of alarms included in the report can be set by assigning a filter to include alarms based on their process area, functional classification, enable / disable status, etc..

Figure 1 -      Defining the Audit Report Scope from DeltaV SAM

Figure 2 -      DeltaV Runtime Audit Report (Example)

DeltaV Audit Reports are a simple and effective way to audit a subset of key alarm attributes. For a more rigorous and complete audit of all alarm attributes, a configuration snapshot generated by Bulk Edit or via SAM XML can be compared with an MADB (SILAlarm). 

Figure 3 -      Comparison of Attribute Audit via different methods

Enforcement, which is the automatic verification and restoration of alarm attribute values, can be exercised from SILAlarm or using the DeltaV Runtime Add-In for Excel.

For more information check out the exida webinar: Alarm System Auditing and Enforcement – The Why and the How

References: 

“Management of Alarm Systems for the Process Industries”, ANSI/ISA-18.2-2016 

“Using DeltaV Audit Reports with SILAlarm™ V2.12”, 

https://emersonexchange365.com/products/control-safety-systems/f/deltav-discussions-questions/8862/compare-between-online-and-offline/19656#19656