Duevi DIRFE, Instructions For Use Manual

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To obtain a reliable detection, it is recommended to mount the detector in the way that the intruder crosses beams
perpendicularly and not with frontal approach.
Fig. 2 – Detection area crossing types
Once fixed the detector, to orient the heads, it is recommended to slightly loosen screws closing of joints.
Proceed with the “calibration” of detectors sensitivity, starting from a low sensitivity condition (trimmer rotated completely
counter-clockwise) and heads oriented downwards. Increase progressively sensitivity and heads orienting until you obtain
a detection only in the area to be protected and no alarm outside the protected area.
Once finished the orienting operation, close tightly joints screws.
Detector cover gives a decreasing of about 30% of beams length.
Maximum range declared already considers cover decreasing.
During adjustment, perform each test with the cover on the sensor.
Infrared detector is sensitive to the “amount of heat” produced by a moving body. The maximum range of the sensor (measured in
meters) is referred to a
human body .
However the same “amount of heat” may be produced by a smaller body at lower distances, or by a larger one at greater distances. It
should be considered therefore that the range of any passive infrared sensor is a RELATIVE measure (referring to a human body) and
NOT ABSOLUTE.
Range (m)
Sensor
Crossing of beams: correct Frontal approach: not recommended