Aritech DDI78 Manual De Instalación página 7

contact to the housing, but is not otherwise connected to the electronic
circuitry. The other end of the shield should be connected to a common
ground (generally the same ground used for the power supply or control
unit). Regardless of the type of cable used, Terminal 1 (Housing GND)
should always be connected to a good earth ground.
4. A
DJUSTING THE
n Range Control Switch
The Range Control adjusts the overall size of the sensor's detection area.
It may be necessary to set the sensor at the higher settings (70, 80, 90
and 100 percent of maximum) to attain the desired protection pattern
coverage.
Note: Although the sensor can be set at the maximum range and operate
properly, the "rule of thumb" is to set it at the lowest setting to attain the
desired range.
n Sensitivity Control Switch
The Sensitivity Control adjusts the amount of movement required for an
alarm condition. The Sensitivity Control is very precise as the DDI78 can
determine the exact "distance in cm" that an object must move to initiate
an alarm. The following table shows the movement required based on
the setting.
Sensitivity
Highest
Lowest
VERY IMPORTANT: The Sensitivity Control is the most critical
adjustment for false-alarm-free operation. It is best to set in
the lower sensitivity settings.
The DDI78 provides good detection in all ten sensitivity settings with
respect to movement toward or away from the sensor. Keep in mind that
in the lower sensitivity settings (1, 2, 3, 4, and 5) transverse detection
("crosscatch") is very sluggish. Therefore, it is important for the sensor
to be located so that the most likely direction of travel is slightly toward
or slightly away from the sensor.
Proper mounting location of the DDI78 will enable lower sensitivity
settings. Lower sensitivity settings will enhance false-alarm-free per-
formance.
Recommendation: Each sensor should be periodically walk-tested to
ensure that the required detection is attained.
n Enhanced Bird/Animal Immunity Control Switch
A two-position switch adjusts the sensor's immunity to birds and small
animals. Note: The DDI78 sensor is shipped in the Standard Immunity
Setting.
Standard Immunity Setting - Offers excellent immunity with respect
to birds and small animals and is the setting in most applications. The
DDI78 sensor will provide good nuisance alarm rejection as well as good
detection sensitivity in the Standard Immunity Setting.
S
ENSOR
Setting
10
9
8
7
6
5
4
3
2
1
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Movement
(cm)
10
20
30
40
50
60
70
80
90
100