Instar IN-MOTION 300, Быстрое руководство по установке

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4 How does it work?
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What do I need to consider before installing the sensor ?
The standard sensor coverage area is approximately conical in shape and is
broken up into zones by the Fresnel lense - see below for a top view of cover-
age area. The target to be detected must pass either into or out of one of these
zones in order to be detected. Small targets can sometimes move between
these zones and not be detected because they never pass into or out of a zone.
Sensor Coverage Area
Top View
Sensor Coverage Area
Side View
Targets moving directly toward or away from the sensor may sometimes es-
cape detection as PIR sensors tend to be less sensitive to this type of movement
- this is most likely to occur with small targets.
While not an absolute requirement, for the best results a target should move
across the coverage area. Note how the zones are spaced wider near the end of
the sensors range, and are shorter at the edges of the coverage area. At the far
end of the detection area the sensor is covering the largest number of square
feet. As you move closer to the sensor its coverage area decreases. A small tar-
get near the end of the sensors range crosses only a tiny percentage of the total
covered area and might escape detection. A small target close in to the sensor
crosses a greater percentage of the covered area and is much easier to detect. A
target’s size, distance from sensor, and surface temperature play an important
part in the sensors effective range.