Diffuse sensors

The emitter and receiver are in the same housing. The emitter sends out a beam of pulsed red or infrared light which is reflected directly by the target. When the beam of light hits the target (at any angle), it is diffused in all directions and some light is reflected back. The receiver sees only a small portion of the original light, switching the sensor when a target is detected within the effective scan range.

Features:
The sensing range depends largely on the reflective properties of the target's surface.
Suitable for distinguishing between black and white targets.
Relatively large active range.
Positioning and monitoring with only one sensor.

Typical applications:
Distinguishing and sorting of objects according to their volume or degree of reflection.
Counting of objects.
Presence detection of boxes.

Diffuse sensors with background suppression

A special development of the diffuse sensor. The beam of light is closely focused, therefore able to distinguish a target within a precisely defined scan range and ignore targets outside the range.

Features:
Sensing range largely independent of the color and surface of the target.
Detects small objects.

Typical applications:
Sorting objects without concern for the background color, purely on their distance from the sensor.
Sensing contents within transparent packaging.

Retro-reflective sensors

With the emitter and receiver in the same housing this sensor transmits a pulsed infrared or red light beam which is reflected back from a "triple prism" reflector or reflective tape. The sensor switches when the light beam is interrupted. These devices recognize objects independent of their surface qualities, as long as they are not too shiny.

Features:
Large sensing range
Matte finished objects are recognized independent of their surface properties.

Typical applications:
Height detection of stacked objects.
Control of randomly positioned objects on a conveyor.

Retro-reflective sensors with polarization filter

Retro-reflective sensors with polarization filters correctly recognize highly reflective objects. The polarizing filter prevents false switching with shiny objects. Only the stray and unpolarized light from the reflector actuates the sensor.

Features:
Similar to retro-reflective sensors, but with the added advantage of being able to accurately distinguish shiny objects.

Typical applications:
Monitoring shiny cans on a conveyor belt.

Through beam sensors

Fiber optic devices for glass fiber

The application possibilities of some standard diffuse sensors can be enhanced with screw-on type fiber optic cables. Fiber optic cables are available in both Diffuse and Through beam configurations. The attachment of fiber optic cables gives a shorter but more accurate sensing range, allowing the detection of small objects.

Typical applications:
Detecting small objects.
Monitoring flow of bread in an oven.
Detecting absence/presence of lids on a process filling line.

Fiber optic devices for cross section converters

The complete range of fiber optics can be connected to amplifiers with analog outputs. Applying a cross section converter, as shown in the drawing, the output signal is proportional to the covered area of the fiber optic. The height and therefore the orientation of a target can be simply monitored. The slope and zero points of the output signal are adjustable by potentiometer.

Typical applications:
Sorting various objects.
Measuring of diameters and heights.
Checking for double sheets.

Fiber optic devices for plastic fiber

Typical applications:
Detecting small objects.
Monitoring flow of bread in an oven.
Detecting absence/presence of lids on a process filling line.

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