Chapter 8 Alarms
Page 8.3
8.1.5 What the Alarm Status Display tells you
A typical Alarm Status Display is shown in Figure 8.2. The display lists, for each type of alarm (System, Input or
Limit), the number of alarms that are live and new.
•New alarms are alarms that have been received but not accepted.
•Live alarms are alarms that refer to conditions still active.
An example of a live alarm is when there is a fault in the system. This produces two alarms - one when the fault
first occurs (‘ON’) and the second when it is put right (‘Off’). If only the first alarm of the pair has been received,
the alarm is said to be live because the condition still exists.
The number of live alarms tells you how many faults are still active. If you look at the Historical Alarm Log this tells
you more about these faults.
8.1.6 What the entries in the Historical Alarm Log tell you
Figure 8.3 shows a typical display and the function of the relevant buttons.
Key to figure:
1. Indicates if there are entries BEFORE this one
2. Alarm is either ‘ON’ (fault occurrence) or ‘OFF’ (fault cured).
3. Type of alarm
4. Indicates alarm not accepted
5. Accept this alarm
6. Alarm description and extra identifier to qualify the alarm
7. Clear this alarm entry
8. Date and time that this alarm (message) was raised.
9. Identifies a metering-run/stream - not applicable to single
meter-run/stream software
10. Indicates that there are alarm entries AFTER this one
11. Scroll DOWN through the entries
12. Scroll UP through the alarm entries
13. Clear all alarm entries.
Figure 8.3: A typical entry in the log
Each alarm has its own entry in the Historical Alarm Log that tells you:
•Type of alarm
Whether it is a System alarm,Input alarm or Limit alarm and if the alarm is ‘on’ or ‘off’.
•Extra identifier for the alarm
This is not always shown for every entry but, where it is shown, it could be one of the following:
•A digit This indicates the channel number on which the fault occurred.
•A letter H and L are for high and low Limit alarms, S is for a step alarm.
•Date and time
The date is in the format DD-MM-YY and the time HH:MM:SS. These are entered automatically by the
system when the alarm is received. The time is accurate to within one second.