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Unformatted text preview: illator (1) External voltage (6) Evaluation unit (2) Internal constant voltage supply (7) Triggering stage (3) Active zone (ultrasonic transducer) (8) Switching status display (4) Switch output (9) Output stage with protective circuit (5) Fig. 7.1.1: Block circuit diagram of an ultrasonic proximity sensor The proximity sensor can be divided into three main modules, the ultrasonic
transducer, the evaluation unit and the output stage. A short pulse briefly triggers
the ultrasonic transmitter. This is usually a piezo-electric module, e.g. on the basis
of piezo-oxides. © Festo Didactic GmbH & Co. KG • FP 1110 107 7. Ultrasonic proximity sensors The ultrasonic transmitter emits sound waves in the non-audible range at any
frequency usually between 30 – 300 kHz. In most cases, the ultrasonic transmitter
changes from emission to reception, i.e. now operating in the sense of a
microphone. Filters inside the ultrasonic proximity sensor check whether the sound
received is actually the echo of the emitted ultrasonic waves. 1 V 2 td to
te tp Emission pulse (1) Pulse duration...
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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