Comander Perimeter Security System
Engineering and Installation Manual
Page 63 of 72
5.5.5.1 Grouping Zones in Pairs
One of the most common arrangements is for sensor signals
to be brought back to the electronics in pairs, with a junction
box at the meeting-point of two zones being used to connect
the two Interceptor cables to a multi-pair feeder cable. Like
the EOL Termination boxes, the junction box must also be
protected with a Lid-Tamper microswitch.
An extra pair within the feeder cable is used to bring the
Tamper microswitch signal back to the Marshalling Box as a
Monitored Contact circuit. The top two terminals connect the
microswitch tamper signal into a separate pair within the
feeder cable. Thus two zones of Interceptor cable require
three pairs of feeder cable when allowance is made for the
extra Junction Box Tamper.
5.5.5.2 Daisy-Chaining Zones
If a feeder cable with at least five pairs is used, it is then
possible to continue the run of feeder to another such
meeting-point of two zones and connect the sensors from
those zones as well.
The sensor signals from the two alpha cables are connected
into two pairs of the outgoing feeder, and the microswitch
tamper signal is linked into a third outgoing pair.
Any pairs of the incoming feeder which are already carrying
a sensor or tamper signal are directly connected to a pair of
the outgoing feeder while all unused pairs are cut off.
5.5.6 Junction Box Tamper Signals
If it is not a site requirement to monitor every junction box lid tamper independently,
then the number of pairs used can be reduced. The microswitch tamper signal from this
second junction box may be connected in series with the incoming pair which is
carrying the lid tamper from the previous junction box, creating one combined tamper
signal. In the event of sabotage the system would then be able to determine that one of
the junction boxes had been opened, but not which one.
Interceptor Interceptor
Feeder
Interceptor Interceptor
Feeder
In
Out
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