ABB AWT420 - Process Alarm

AWT420 | UNIVERSAL 4-WIRE, DUAL-INPUT TRANSMITTER | OI/AWT420-EN REV. B
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Process Alarm
Used to configure up to 8 independent process alarms.
Menu
Comment Default
Alarm 1 (to 8)
Source Select the sensor signal for the process alarm source.
Type Select the alarm type:
• High Process/Low Process/High Latch/Low Latch
Tag 
The tag is displayed as a diagnostic message and appears in the Diagnostic Status Bar and on the
Diagnostic View page at Operator.
Trip Set a trip value in engineering units.
Hysteresis Set a hysteresis trip value in engineering units. The alarm is activated at the alarm trip level but
deactivated only when the process variable has moved into the safe region by an amount equal
 and ) below.
Time Hysteresis 
If the alarm trip value is exceeded, the alarm is not activated until the Time Hysteresis value has expired.
If the signal goes out of the alarm condition before the Time Hysteresis has expired, the hysteresis timer
is reset.
Process alarm examples
Figure 32 High and low process alarm action
Figure 33 High and low latch alarm action
Processs Alarm
Exit
Menu
Select
Trip point
Trip point
PV
On On
Off Off
Hysteresis
Hysteresis
High process alarm
Low process alarm
Alarm
state
Alarm
state
Acknowledged
after condition
cleared
Acknowledged
before condition
cleared
Acknowledged
before condition
cleared
Acknowledged
after condition
cleared
Trip point
Trip point
PV
On
On
On
Off
Off
Off
Hysteresis
Hysteresis
High latch alarm
Low latch alarm
Alarm
state
Alarm
state
Alarm
state
Active
Active
Active
Active
LatchedLatched
Acknowledged
Acknowledged
On
Off
Alarm
state