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WL31/WL31TG
1.2.5 VIBRATION OR SISMIC DETECTOR
This detector detects the vibrations of the surface to which it is glued or screwed and it filters them to avoid false
alarms. If applied to a door or window, unlike the lamellar magnetic contact, it is able to signal an attempted
INTRUSION before the door or window is properly open. In fact, the vibrations which cause the alarm to be
generated are produced when the entry is forced.
1.2.6 PASSIVE INFRARED DETECTOR (IR) or VOLUME DETECTOR
This detector measures the fast variations in the infrared track which surveys the controlled environment and it can
be used
to highlight the presence of human beings, animals or “hot” moving objects. The effectiveness of the
detector
and the area it covers can be modified by altering its sensitivity, the “lenses” which keep the checked area
in focus, or by totally covering it. In the anti-theft systems these detectors are used to check large spaces and
unavoidable passages (e.g. corridors), creating a “trap” protection.
1.3 TYPES OF CONNECTION
There are two types of connection between the detectors and the signalling devices to the anti-theft control panel:
wire connection and more recently, wireless or radio connection. Furthermore, there is the possibility to create
hybrid systems which use both types of communication. Each type of connection offers strengths and weaknesses,
which are summarized in the following tables:
1.3.1 WIRE SYSTEM
Strengths
Weaknesses
It is not affected by radio shielding or by radio
connection distances; the control panel can be
positioned in the most suitable place.
It is not affected by radio interferences: the devices
which produce radio frequencies or power lines do
not cause communication problems.
It is necessary to put on cables; all the detectors and
signalling devices must be connected with the
control panel through multipolar cables.
The volume detector positions can hardly be
changed; to move a detector it is necessary to install
a new cable.
The control panel powering requires a network
power (detectors are powered by the control panel).
The installation requires a long time: if there are no
prearrangements
(internal
wall
pipes),
it
is
necessary to position the connection cable under the
skirting boards and to hide the door wire covers, dig
holes in the walls and in the slabs, etc.
This long installation time causes discomfort if the
rooms are lived in.
The wire system is suitable for new buildings where it is possible to set all the pipes necessary for the connection
wires and in all those cases in which radio technology can not guarantee continuous and error-free communication
(interferences and radio shielding)
1.3.2 WIRELESS SISTEM
Strengths
Weaknesses
There is no need for cables; all communication is
made through radio and the components can be
placed in the most suitable position.
The volume detectors can be easily moved in case
of modifications to room furniture positions.
There is no need for network power; all the system
components are powered by long lasting batteries *.
Fast installation: it is sufficient to position the
system components where they are required,
without cables.
The installation time is so short that it does not
cause discomfort if the rooms are lived in.
It is affected by radio shielding; some material can
weaken
radio
waves
and
stop
or
make
communication between devices difficult.
It is affected by radio interferences; sources which
produce electromagnetic waves (e.g. electric
counter, television, computer, electric engines, etc.)
can make the communication between devices
difficult.
It is necessary to have at least one free radio
channel (which means that no other system uses it).
* This is valid for Elkron systems: systems by other producers might require network power for the devices
