Operators Handbook DCU3 – System
6., Main function „Control Loops“
BAEDCU3 - Rev. 4.6 - 0504 6 - 37
6.23 Alarm Limits of Process Values
The DCU3 - system includes alarm handling routines which monitor all process values (measured val-
ues and derived process values), whether they are within their alarm limits. For the monitored process
values the high/low alarm limits are entered via the operator terminal at first. Then the alarm handling
routines can be enabled or disabled for each process value which should be monitored.
The High/Low alarm limits must be within the measuring ranges. If the alarm limits are exceeded, a
warning message is displayed and an acoustic signal is activated. The alarm can be confirmed via the
ACK key, and the next alarm is displayed. An alarm buffer stores up to 20 alarm messages not being
confirmed. The latest alarm is displayed on the alarm line on the screen.
Current process value alarms are shown in the related process display by white letters on red back-
round. Depending on the process value alarm, certain process outputs can be set to their „shut down“
state via locking functions. Such locking functions will be implemented in customized configurations of
the DCU3 - system.
6.23.1 Operating Display
Tag Entry Displayed value or function, required input
LOW LIMIT Input of low limit alarm (LOW) in terms of its physical unit
HIGH LIMIT Input of high limit alarm (HIGH) in terms of its physical unit
ALARM MODE Input of status for alarm monitoring
disab
− Alarm monitoring for high/low alarm locked
enabl
− Alarm monitoring for high/low alarm released
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