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Unformatted text preview: al power on the receiver input
PR divided by the just detectable optical signal power at the switching threshold PT:
PT If the received optical emission is at the switching threshold level, this means β = 1,
i.e. there is no operating margin. If the factor is for instance β = 1.5, then an
operating margin of 50 % is available. 74 © Festo Didactic GmbH & Co. KG • FP 1110 6. Optical proximity sensors Factor β on the one hand depends on the distance between the emitter and the
receiver in the case of the through-beam sensor, between the emitter and reflector
in the case of retro-reflective sensors or between the proximity sensor and object in
the case of a diffuse sensor.
On the other hand, the pattern of the operating margin factor is dependent on
distance s with regard to the individual proximity sensor. Figs. 6.1.3 to 6.1.5
illustrate a number of schematic operating margin curves. 1000
Operating margin factor ß 100
0.01 0.04 0.1 0.2 0.4 1 2 4 m 10 Distance s Fig. 6.1.3: Ex...
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This note was uploaded on 11/01/2012 for the course CHEMICAL 102 taught by Professor Jamesrodriguez during the Spring '12 term at Universidad Politécnica de Cartagena.
- Spring '12