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Distance measurement with background suppression (BS)

This technology is based on the so-called triangulation principle. Also in this case, emitters and receivers are integrated in one housing.
A LED (emitter - TX) beams lights through a lens in a straight line toward the target. The target reflects the light back to the receiver (RX) lens at some angle. The distance between the sensor and the point of reflection (on target side) determines the angle of reflection back to the receiver. The closer the target to the sensor, the greater angle.

The sensor's output is mainly based on the reflection distance from the sensor and not on the amount of reflected light/energy.

Our sensors are based either on mechanical or on electronic background suppression :

• Mechanical background suppression : these devices use two receiving photodiodes elements (RX1 and RX2) in the photoelectric sensor. If the target comes closer to the sensor, the reflected light hits the background decreases and the reflected light hits the receiver element RX2. Thus the sensor differentiates between the target and the background according to which receiver element RX1 or RX2 is hit, i.e. receives the reflected light.

  

• Electronical background suppression : those devices use a position-sensitive device. this device gives an output signal corresponding to where the reflected light strikes its surfaces. As the distance between the sensor and the reflection point changes, the focal point moves up or down the position-sensitive device. The output of the position-sensitive device is compared to a preset value. This value defines the switching point that triggers the output of the sensor.