Siemens 9810 Series, User Manual, Page: 123 / 218

Alarms and alerts
High-speed alarm
High-speed alarms have a detection rate of once every half-cycle.
3-phase alarms
Alarms on 3-phase systems are evaluated per phase and reported for each
phase.
Some alarms, such as the sag/swell alarm, are evaluated per phase, but reported
as a single alarm: Each of the three phases are evaluated for the setpoint
condition individually, but there is only one alarm generated. The alarm pickup
occurs when the first phase exceeds the alarm pickup magnitude for the pickup
time delay. The alarm is active as long as any phase remains in an alarm state.
The alarm dropout occurs when the last phase drops below the dropout
magnitude for the dropout time delay.
Example of over and under setpoint (standard) alarm operation
The meter supports over and under setpoint conditions on standard alarms.
A setpoint condition occurs when the magnitude of the signal being monitored
crosses the limit specified by the pickup setpoint setting and stays within that limit
for a minimum time period specified by the pickup time delay setting.
The setpoint condition ends when the magnitude of the signal being monitored
crosses the limit specified by dropout setpoint setting and stays within that limit for
a minimum time period specified by dropout time delay setting.
Over setpoint
When the value rises above the pickup setpoint setting and remains there long
enough to satisfy the pickup time delay period (ΔT1), the alarm condition is set to
ON. When the value falls below the dropout setpoint setting and remains there
long enough to satisfy the dropout time delay period (ΔT2), the alarm condition is
set to OFF.
EV1
EV2
∆T1
∆T
2
∆T3
Max1
Max2
A Pickup setpoint
B Dropout setpoint
ΔT1 Pickup time delay period (in seconds)
EV1 Start of alarm condition
ΔT2 Dropout time delay (in seconds)
EV2 End of alarm condition
ΔT3 Alarm duration (in seconds)
Max1 Maximum value recorded during pickup period
Max2 Maximum value recorded during alarm period
The meter records the date and time when the alarm event starts (EV1) and when
it ends (EV2). The meter also performs any task assigned to the event, such as
operating a digital output. The meter also records maximum values (Max1, Max2)
before, during or after the alarm period.
Under setpoint
When the value falls below the pickup setpoint setting and remains there long
enough to satisfy the pickup time delay period (ΔT1), the alarm condition is set to
ON. When the value rises above the dropout setpoint setting and remains there
long enough to satisfy the dropout time delay period (ΔT2), the alarm condition is
set to OFF.
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