Page 4 of catalogue Optoelectronic sensors of Rechner Industrie-Elektronik GmbH

TECHNOLOGY

MOUNTING APPLICATION

The IS-120 series comprises Optoelectronic sensors for use as light Sensors (energetic or with background suppression) or as Reflection light barriers. Light transmitter and receiver are both mounted in the same housing. The emitting diode emits radiation with a wavelength of 660 nm with red-light switches or. 880 nm with infrared switches. When hitting the detected object the pulsed light is reflected diffusely and partially impinges on the receiver. With energetic sensors the received energy is evaluated whereby the possible sensing distance is dependent on the colour/reflection characteristics and dimension/design of the object. With light sensors with background suppression the angle of incidence is evaluated and thus the sensing distance is to a great extent independent of the object’s characteristics. For example, these sensors are applicable to detect objects in front of bright or strongly reflecting surfaces.

Infrarotsensor als Lichttaster (Bild 1)

Infrarotsensor als Reflexlichtschranke (Bild 2)

If the optoelectronic sensor is used as an energetic light switch (fig. 1), the object to be detected reflects the transmitted light. The quantity of light measured by the phototransistor depends on the distance, colour and character of the surface of the detected object. White Kodak paper has to be used when measuring the max. range (see technical data). Smaller ranges result when using other colours and sizes.
All specifications are subject to change without notice. (05/2006)

When using the optoelectronic sensor (energetic switch only) as a reflection light barrier (fig. 2) a triple reflector or foil reflects the transmitted light. In this way a much more extended sensing range can be achieved (as of approx. 1 m) than on white paper. In this case the interruption of light by a lower reflecting object is measured. In order to measure the max. range (see technical data) a triple reflector with a diameter of 80 mm has to be used. The use of smaller diameters/surfaces results in smaller ranges. Optoelectronic sensors from RECHNER can operate from an object distance of zero. There is no deadzone. Reflection light sensors with background suppression have a PSD-element (position sensitive device) as receiver. The light spot is visible for easy alignment and the sensing range is adjustable. Since there are no moving optical parts, they are vibration-proof, like all optoelectronic sensors from RECHNER. The pulsed light of the emitting diode is focused on the object and is reflected diffusely. Thus part of the light impinges on the PSD-element. Depending on the object distance the light strikes a certain area of the PSDelement (fig. 3). The output switches when the object distance is smaller or equal.

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RECHNER Industrie-Elektronik GmbH • Gaußstraße 8-10 • D-68623 Lampertheim • Tel. (0 62 06) 50 07-0 • Fax (0 62 06) 50 07-36 • e-mail: info@rechner-sensors.de • www.rechner-sensors.de