Principles Of Function - ABB Busch E-contact System Manual

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.
Infrared sensor technology (IR sensor technology)
1 2
1A
100A
Fig. 13: Function principle of 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
Passive infrared sensors (passive IR sensors)
Fig. 14: Passive IR sensor
Passive IR sensors are designed so that they react only to a change in heat radiation. E.g.
during 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).
System Manual 2CKA001473B9577
Information about planning and application
3 4 5 6
0,4µm 0,7µm 0,1cm
│54