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Alarms and events
DAS is primarily intended to help operators deal with high-alarm situations like trips where
multiple alarms related to the same event are triggered in quick succession. It can therefore be
a useful strategy for dealing with "downstream" alarms resulting from equipment trips (or
even unit shutdowns or startups). For example, if a pump shuts down or a compressor trips,
you might want to use DAS to automatically suppress any consequential low-flow (or low-
pressure) alarms.
Although suppressed alarms are hidden from the default (unfiltered) view of the Alarm
Summary, the number of alarms currently suppressed is shown in the summary statistics at the
bottom of the Alarm Summary, and operators can use the (suppressed alarms) view to see
which alarms are currently suppressed.
DAS can be used for alarms on any of the following point types: CDA, SCADA, DSA, point
server, or third-party OPC.
Attention:
DAS should only be used to suppress alarms that are of no direct operational
relevance to operators and that do not require an operator response at the time.
Before implementing DAS it is very important that you read the alarm design and
application guidelines in the Server and Client Planning Guide as well as the
configuration guidelines and scenarios in the Server and Client Configuration
Guide.
Planning and application guidelines for Dynamic Alarm Suppression
Dynamic Alarm Suppression (DAS) is an advanced form of alarm management that should
be designed, implemented and tested by appropriate individuals such as the engineers who are
responsible for the equipment in question.
Before designing, implementing or modifying an alarm system, it is recommended that
engineers familiarize themselves with industry standards such as the EEMUA's Publication
191 Alarm Systems: A Guide to Design, Management and Procurement, the ASM
Consortium's guideline Effective Alarm Management Practices, and the ISA-18.2 standard
Management of Alarm Systems for the Process Industries.
When planning your system, bear in mind the following:
As a general principle, keep your DAS strategy simple and conservative to ensure that
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important alarms requiring operator attention are not inadvertently suppressed.
A well-designed and well-managed alarm system is an important precondition for alarm
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suppression. It is therefore strongly recommended that, before implementing DAS,
sites:
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