6
The sensor principle of operation is based on generate an electromagnetic field
between Tx and Rx. This field forms a volumetric detection zone in the form of a
long ellipsoid of rotation. The sensor registers changes of the field when an
intruder crosses the protected zone.
5.1.2.
An intruder crossing the detection zone causes changes of the signal amplitude in
Rx. The signal passes through the amplifier and is compared with the thresholds
value according to the algorithm. If the signal change on Rx input is provoked by a
person passage, then Rx generates an alarm, breaking actuating relay contacts. The
signal changes depend on: height and weight of the intruder, place of the sector
crossing, its relief and speed of the movement.
5.1.3.
The signal on Rx input can be changed under the influence of other interference
factors: precipitations, vegetations, small animals, electromagnetic interference,
swinging of tree branches or gates, crossing the detection zone and which are
commensurable with intruder movements. Other reasons, e.g. location of extensive
constructions in the detection zone or near it (fences, walls), irregularities, snow,
and grass can influence on the Rx input signal. In these cases the detection zone
form is distorted because of re-reflections and interferences. Multi thresholds
operation algorithm permits to reduce the number of false alarms.
That’s why one
should observe the recommendations of the subsection 8.1!
5.2.
Adjustment, control and indication parts
5.2.1.
The values of the Rx
thresholds are set by a user during the sensor operation and
with the help of the threshold controller «MIN-MAX». The thresholding is
performed by the slow rotation of the resistor axis with a screwdriver. In this case
the threshold value changes from minimum (MIN) to maximum (MAX).
5.2.2.
The input signal is controlled with the tester on the jack, marked "TEST" (test
jack).The more the «TEST» voltage is, the more the Rx input signal is and vice
versa. The sensor is operable at the «TEST» voltage from 0,1 up to 4,8 V.
5.2.3.
The light indicator «PROTECTION» informs about the sensor operation mode:
-
continuous light means the sensor standby state;
-
the indicator switching off for 3 sec means the alarm generation.
An interrupted light of the indicator «PROTECTION» is possible in the case of
quick installation of the amplifier. To reduce the power consumption, the indicator
«Protection» goes out after 10 min of the sensor operation in the standby state if
there were no pressures on the button «AGC», turn of the thresholds controller,
change of the sensor in the alarm mode. In this case the indicator disconnection
doesn’t influence on the state of the relay contacts.
5.2.4
. During Rx and Tx adjustment on the upper limit of the
directional patterns, the
amplifier changes the adjustment mode with a big time constant to the mode with a
Summary of Contents for FORTEZA-300
Page 17: ...17 Fig 8 3 ...