This preview shows page 1. Sign up to view the full content.
Unformatted text preview: (td) Echo transmission time (te) Echo (2) Oscillation decay time (to) Pulse interval (tp) Fig. 7.1.2: Principle of distance measurement by evaluating the transmission time of ultrasonic pulses The speed of operation of ultrasonic proximity sensors is limited by the maximum
pulse repetition frequency which, depending on design, can range between 1 Hz and
A major advantage of ultrasonic proximity sensors lies in the fact that these can
detect a wide range of different materials. Detection is independent of shape, colour
and material, whereby the material can be solid, fluid or in powder form. Testing is
not affected by dusty, steamy or smoky atmospheres. 108 © Festo Didactic GmbH & Co. KG • FP 1110 7. Ultrasonic proximity sensors Ultrasonic proximity sensors are generally available in the form of diffuse sensors,
where the emitter and received are in one housing. In addition, ultrasonic barriers
are available, which have separate emitters and receivers.
Preferred areas of application for ultrasonic proximity sensors are:
• Storage facilities
View Full Document
- Spring '12