
80
High Annunciate Alarm Action
Low Annunciate Alarm Action
Alarm On
Alarm acknowledged
by operator
Hysteresis
Process
Variable
Alarm Off
Trip Point
Trip Point
Alarm Off
Hysteresis
Process
Variable
Alarm On
Alarm acknowledged
by operator
Deviation exceeded –
fast rate alarm
becomes active, slow
rate alarm becomes
inactive, new period starts.
Deviation below limit
at end of time period –
fast rate alarm
becomes inactive, slow
rate alarm becomes
active.
Deviation below
limit at end of time
period – alarm
becomes inactive.
Alarm On
Alarm Off
Fast Rate Alarm
Period
Deviation
Deviation
Deviation exceeded –
fast rate alarm becomes
active, slow rate alarm
becomes inactive,
new period starts.
Deviation below limit
at end of time period –
slow rate alarm becomes
active, new period starts.
Alarm On
Alarm Off
Slow Rate Alarm
…4
CONFIGURATION
Fig. 4.13 High/Low Annunciate Alarms
Fig. 4.14 Fast/Slow Rate Alarms
…4.6.4
Alarm Configuration