RSView Supervisory Edition Installation Guide

Alarm suppression
You can suppress alarm monitoring for tags. This is useful for testing
or for performing repairs or maintenance on a piece of equipment.
To suppress alarm monitoring for tags, use the RSView SuppressOn
command. To view a list of the tags not being monitored, use the
Suppressed List. You can also turn monitoring back on from this list.
Alarm functions in expressions
When a tag goes into alarm, or an alarm event occurs, certain
information about the alarm is recorded in the value table together with
the value of the tag or alarm event. Using expressions, information
about alarms can be retrieved on a tag-by-tag basis. For information
about alarm events, see page 11-17.
IMPORTANT
If a graphic display requires more than 20 alarm
functions, for performance reasons it is better to use
these alarm functions in derived tags instead.
For example, if the system detects that a tag is in alarm, it sets an
internal alarm bit, and then resets the bit when the tag is out of alarm.
The following expression checks if a tag is in alarm:
ALM_IN_ALARM (tag)
where tag is the name of the tag you want to check for alarms. When a
tag is in alarm, the expression result is 1. When a tag is out of alarm,
the expression result is 0.
One way to use this expression is to animate the visibility of a graphic
object in a display. When the tag goes into alarm, the
ALM_IN_ALARM expression is set to 1, making the object visible.
This is an effective way to draw the operator’s attention to the alarm.
11–14 RSView Supervisory Edition User’s Guide