Querying alarms and events

Querying Alarm and Event data is helpful in keeping track of your production environment. For example, as an operator, you could query the data to find out answers to these questions:

• How often alarm events occur?

• Where in the facility they occur?

• How critical the alarms are?

• How quickly they are addressed and cleared?

  Datetime in Alarm and Event Queries

All queries of alarm and event data must include at least one datetime column.

Alarm and event queries use two ways to express time:

• UTC time
  This format is used by EventTimeUtc.

• Local time for the location of the Historian server
  This is used by columns like EventTime.

The value of wwTimeZone affects any datetime recorded in local time, but does not affect EventTimeUtc.