ABB SM1000 User Manual page 59

...4.6.4 Alarm Configuration
Process variable goes
above trip point but
alarm is not activated
because enable signal
is low (Alarm Disable).
Process
Variable
Alarm Enable signal is
switched On. Alarm delay
timer is started.
Process variable goes
above trip point but
alarm is not activated
because alarm delay
time has not expired.
Delay Time
Alarm delay timer expires,
alarm is now enabled.
Alarm is activated
because process variable
is above trip point.
Fig. 4.16 Delayed High/Low Process Alarms
Process variable goes
Process variable goes above trip point, alarm is
below trip (hysteresis) activated (alarm is
point therefore alarm enabled and delay time
is de-activated. has expired).
Alarm Enable signal is
switched Off. Alarm is
disabled immediately.
Alarm de-activates.
4 CONFIGURATION...
Trip Point
Hysteresis
Alarm Enabled
Alarm Disabled
Alarm On
Alarm Off
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