Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 216)

F ACTORY T ALK V IEW S ITE E DITION U SER ’ S G UIDE
11–4
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Example: Alarm thresholds
In this example, a tag’s value changes as it monitors a motor’s revolutions per minute
(rpm). An X in the illustration shows when the tag goes into alarm, and an O shows when
the tag goes out of alarm.
With the given threshold settings, the motor must run between 2,000 rpm and 3,000 rpm,
or an alarm is triggered.
If the check box, Generate alarms when approaching normal operating range, is
selected in the Alarm Setup editor, alarms will occur when the motor speed falls below
5,000 rpm and 4,000 rpm, and when it rises above 1 rpm and 1,000 rpm.
If the motor speed It triggers an alarm of this severity
exceeds 3000 rpm 8
exceeds 4000 rpm 4
exceeds 5000 rpm 1
falls below 5000 rpm* 4
falls below 4000 rpm* 8
falls below 2000 rpm 8
falls below 1000 rpm 6
falls below 1 rpm 4
5000
4000
2000
1000
Thresholds
Threshold
values
Alarm
severity
levels
Time
*
*
Increasing
Decreasing
6
5
4
3
2
1
1
4
8
8
6
4
Thresholds must be set
3000
Safe zone
X X
X X
X
X O
O
up in ascending order
1