CIAS Elettronica S.r.l. Ed. 1.5
Installation Handbook Page 52 of 57 MANTA 50 – 80
l. Select
position 4
on the “function switch”
SW1
. The
alarm thresholds
adjustment phase and
the
walk test
phase are activated. The two alarm thresholds are set above and below the
quiescent field value. They are higher than the corresponding pre-alarm thresholds and are
used to evaluate, at the end of the analysis process, if the field value change is enough to
generate an alarm event.
To
read
the current alarm threshold values proceed as follows:
•
Rotate decimal switch
SW2
(tens column) until the second red led (
D9
) comes ON
•
Rotate decimal switch
SW3
(units column) until the first red led (
D8
) comes ON
The values read will be between 01 and 80 (
default value 30
). Decreasing the threshold
value increases the sensitivity and the beam dimensions.
To
modify
the current value and increase the sensitivity it is necessary to select, using the two
switches SW3 and SW2, a lower value and then push the button S3. To decrease the
sensitivity, it is necessary to select, using the two switches SW3 and SW2, a higher value and
then push the button
S3
.
During this phase (
SW1 position 4
) it is also possible to perform the walk test. The barrier
works using the current thresholds, and any change in received MW field strength (for
example, due to an intruder moving in the sensitive beam), causes the activation of a pulsed
sound produced by the on board buzzer. The pulse frequency is proportional to the level
change of the received microwave signal. If the pulse frequency increases it means that, the
level change of the received microwave signal, has increased and therefore that the intruder
has penetrated more deeply into the protection beam.
If an alarm event is generated at the end of the analysis process, the sound of the buzzer
becomes continuous (not pulsed). This allows the actual dimensions of the protection beam to
be checked and also to verify if something is moving in the protected area, such as poorly
constructed or maintained fences that can cause problems.
m. Select
position 5
on the “function switch”
SW1
. The
masking thresholds
adjustment phase
is activated. The two masking thresholds are set above and below the absolute installation
field value (VRAG) memorized during the phase 2 (see previous point j). They are used to
check if changes in the received absolute microwave field are large enough to decrease or
eliminate the detection ability of the barrier. A thick layer of snow can produce this kind of
change, but someone can try to produce them intentionally, in order to mask the receiver.
To
read
the current masking
threshold values proceed as follows:
•
Rotate decimal switch
SW2
(tens column) until the second red led (
D9
) comes ON
•
Rotate decimal switch
SW3
(units column) until the first red led (
D8
) comes ON
The values read will be between 01 and 80 (
default value 60
)
Decreasing the threshold value will increase the sensitivity of the anti masking evaluation.
To
modify
the current value and increase the sensitivity (smaller changes produce masking
alarm) it is necessary to select, using the two switches SW3 and SW2, a lower value and
then push the button S3. To decrease the sensitivity (bigger changes produce masking
alarm), it is necessary to select, using the two switches SW3 and SW2, a higher value and
then push the button S3.
n. Select
position 6
on the “function switch”
SW1
. The
upper
pre-alarm threshold
adjustment
phase is activated. During phase k the two pre-alarm thresholds are set to the same value. By
increasing the value of the higher pre-alarm threshold, it is possible to activate the
Fuzzy
Side Target Discrimination (FSTD)
system. This unique system present in MANTA barriers,
allows it to filter, or completely reject, signals generated from something moving on either side
of the protection beam. For example: badly fixed fences or bushes. The resulting beam has
an ellipsoidal shape.
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