Procedure for transmitting frequency comparison of an ultrasound feed switch and an ultrasound feed switch with transmitting frequency comparison

摘要

The method involves using an oscillator (16) to excite an ultrasonic transducer (2) at a frequency which depends on the amplitude of a control voltage applied to the oscillator. As a result, the ultrasonic transducer emits an ultrasound signal which it receives after reflection. The echo signal is converted into an electrical signal for processing in the proximity switch (1). The control voltage is varied by a microprocessor (4). The consequently varied electric signal which is proportional to the amplitude of the received ultrasound echo signal is evaluated w.r.t. its amplitude, e.g. by comparison with a reference, and the result of the evaluation and the corresponding setting parameters are stored in memory.