User manual

B - 20 Magelis
1. Introduction: Display unit operating concepts
Exception for priority 0
If priority 0 is allocated to an alarm page, when the alarm appears on the
control-system architecture:
- The alarm page is not displayed, but stored in the alarm list, thus the
current display will not be disturbed.
- The alarm indicator light blinks to signal the alarm.
When an alarm is activated, it is stored in the alarm list by the display
unit.
 Appearance types
There are several types of appearance for an alarm page.
Alarm pages can be:
- Displayed directly on the screen
- Printed directly (data-stream printing)
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- Stored in the list of current alarms
For more information, see chapter C, section Page appearance types,
Page 30.
 Storage principle in the alarm list
If the alarms have equal priority, they are stored from the oldest to the
most recent.
If the display unit is available (i.e., not occupied by a higher-priority
display), the oldest alarm is displayed. In a control system it is often the
oldest alarm, which is the most interesting, as the more recent alarms
are often a consequence of the fault signaled by the first alarm (classic
case of bursts of alarms).
If higher-priority alarms appear:
- They are stored at the top of the list.
- If the display unit is available (i.e., not occupied by a higher-priority
display), the highest priority new alarm is displayed.
XBT ref. Note
N200 No alarm management
N200/N400/N410
NU400
R400/R410
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