Information about planning and application
System Manual 2CKA001473B9426
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4.1.2
Principles of function
Infrared radiation, also called heat radiation, consists of electromagnetic waves. Every object
transmits a characteristic heat radiation, depending on its specific temperature.
The detection of movement depends on the mounting height and the "free view" of the device.
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1A
100A
0,4µm 0,7µm 0,1cm
Infrared sensor technology (IR sensor
technology)
IR radiation can be detected with IR
sensors and transformed into electric
signals. As these sensors only receive
and do not transmit IR radiation, they are
also known as "passive IR sensors".
[1] Gamma
[2] X-ray
[3] Ultraviolet
[4] Visible
[5] Infrared
[6] Radio waves
Fig. 7:
Function principle of IR sensor technology
Passive infrared sensors (passive IR
sensors)
Passive IR sensors are designed so that
they react only to a change in heat
radiation, e.g., in event of movement.
The transmission range of passive IR
sensors is physically dependent on the
temperature. The reference amounts to
21°C. The transmission range reduces in
a warmer environment.
If heat radiation is constant, no signal is
generated. A room being heated alters its
heat radiation only very slowly in
comparison. It is therefore possible to
detect human movements (heat
movement).
Fig. 8:
Passive IR sensor