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Unformatted text preview: of detection
and can be mounted outside possible danger areas. Exercise 6.3 Operating reliability of optical proximity sensors
By means of modulating light emission, it is possible to improve the protection of
optical proximity sensors against the influence of surrounding light. This means that
their sensitivity to interference as a result of ambient light is reduced.
The light emitter pulses the emissions at a specified frequency actuated by a signal
generator. The generator signal is transmitted to the logic module of the signal
receiver. The signals are checked as to their compatibility and an output signal is
generated only if this condition is met.
Another possibility is to suppress the ambient light by means of a bandpass, which
only allows the emission frequency of the emitter to be passed.
In the case of optical proximity sensors operating in the infrared zone, additional
daylight filters are installed. This further reduces the effects of the surrounding light. 262 © Festo Didactic GmbH & Co. KG • FP 1110 16. Solutions Exercise...
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- Spring '12