SM3000
Multipoint Videographic Recorder
6 Configuration
IM/SM3000–EN Rev. L
95
Fig. 6.18 Delayed High/Low Process Alarms
Hysteresis
Alarm On
Alarm Disabled
Alarm Enabled
Trip Point
Alarm Off
Delay Time
Process
Variable
Process variable goes
above trip point but
alarm is not activated
because enable signal
is low (Alarm Disable).
Process variable goes
below trip (hysteresis)
point therefore alarm
is de-activated.
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.
Alarm delay timer expires,
alarm is now enabled.
Alarm is activated
because process variable
is above trip point.
Process variable goes
above trip point, alarm is
activated (alarm is
enabled and delay time
has expired).
Alarm Enable signal is
switched Off. Alarm is
disabled immediately.
Alarm de-activates.