TM 5-6350-275-24&P
1-20. ALARM GENERATION. Alarms are generated to draw the operator's attention to significant system events, such
as the triggering of an intruder detection device or the failure of a communications cable. They are shown by messages
which appear on the monitor and an audible warning tone emitted by the workstation. Each message can contain up to
three lines of text and includes the condition which caused the alarm to be generated, the time, and the identity and
location of the equipment concerned.
a. The conditions which cause alarms to be generated depend on the type of equipment being monitored.
Equipment which is monitored by status points can generate alarms each time a change is detected when an
exceptional condition arises.
b. Alarms for communications cables or wires can be generated to report the conditions: Failing, Failed, and
Recovering. Failing means that the PMC has been unable to communicate successfully with a RADC following a
pre-determined number of attempts. Failed means that the number of failures is so great, the cable should be
considered inoperable. Recovering alarms are used to indicate significant improvements in a cable's "health".
c. Alarms which reflect the condition of a RADC's cables are termed Telemetry Alarms. Two other types which fall
into this category are: RADC Failure alarms and Point Failure alarms. An RADC Failure Alarm is generated when
the master station is unable to communicate with an RADC, implying that the problem lies within the RADC itself
rather than the communications link(s). Point Failure Alarms indicate that the PMC has not received status
information for a particular item of equipment and also imply that the problem lies within the RADC. In both cases,
the nature of the alarms suggests that some form of maintenance will be needed on the RADC concerned.
1-21. ALARM QUEUES. An Alarm Queue is a place in which groups of logically or geographically related alarms are
maintained. There are 16 alarm queues available. Those used are assigned both a title, which indicates the type of
alarms the queue contains, and a reference number in the range 1 16. For example, an alarm queue entitled Security
could be used to store all alarms relating to security equipment while another, entitled Telemetry, could be used to
maintain telemetry alarms.
a. When an alarm is generated, it is placed in up to four of the available alarm queues and is also tagged with the
current time and a priority level. The priority level is a number in the range 1 16 and determines the order in which
alarms are stored within each queue. Level 1 is the highest priority and is assigned to alarms which are of greatest
importance to operators, such as those indicating intrusion into high-security areas. Level 16 is the lowest level and
is assigned to the least significant alarms.
b. The highest priority alarm within each of up to four queues is presented to operators by a specially reserved area
of the display called the alarm frame. Typically, each message appearing in this frame contains only one line of text,
part or all of which may flash in order to visually alert the operator.
c. There are three processes which can be undertaken on an alarm; it can be acknowledged, cleared, or deferred.
Acknowledgment is normally the first course of action and means that the alarm has been accepted and the required
operational procedures have been undertaken. When an alarm is acknowledged, it is tagged as such by the system
and the next alarm of highest priority replaces it at the top of the queue.
Following acknowledgment, and the satisfactory conclusion of the incident, alarms can be cleared. Clearing an
alarm results in its being removed from the appropriate queue. Alarm clearing may be undertaken automatically
when the condition which caused the alarm ceases.
The deferral process enables alarms to be set aside for processing at a later time and is used on alarms which
cannot be acknowledged or cleared immediately. Deferred alarms are held in a separate section, and only appear in
the alarm frame when there are no undefined alarms held within a queue. Operators can display deferred alarms by
specifically requesting a list of the deferred section.
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