Reflex photoelectric sensor SENSOPART

Photoelectric proximity switch FT 20 RL-PSM4

Scanning range 40 ... 150 mm
Laser red light 650 nm
Laser protection class 2
Miniature line
Teach-in / key lock by push of a button / control line
N.O./N.C. selectable
Also available with 3-pin connector
Switching frequency: 4000 Hz

The photoelectric proximity switches combine transmitter and receiver in one housing.The light emitted by the transmitter is reflected by the target object.The receiver evaluates this reflected light.The advantage of this method is that no reflector is required.
As the proximity switch evaluates the reflected light and its energy, the scanning range of conventional sensors (also called energetic optical sensors) depends to a great extent on the colour of the target object and on its surface.
Because of the bad reflection properties of dark materials, the sensing distances of energetic sensors are reduced on those surfaces. The type of reflection depends on the structure of the surface.
Proximity switches, which are based on energetic evaluation, are ideally suited to the detection of larger objects or of objects whose colour and surface structure are constant.
A further field of application for energetic switches is the evaluation of the different reflectance properties of different colours. For example, energetic switches are capable of detecting a grey mark in front of a white background. The different reflectance behaviour of different colours is purposely exploited during this process. The different sizes of light spots should be observed for the detection of contrast marks. The smallest light spot is achieved with the energetic laser contrast sensor FT 20 RL.

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