Ultraschall-Füllstandsmessung nach dem Impulslaufzeit-Meßprinzip mit verbesserter Echoimpulserkennung

Level measurement using ultrasonics is based on the principle of determining the pulse transit time. The outgoing signal of the ultrasonic sensor is received simultaneously and separately by a pulse detector and an envelope detector. To reduce uncertainty of measurement when measuring the outgoing signal the pulse detector is processed by using the group average method. The outgoing signal of the envelope detector is evaluated applying a new dynamic average curve which is constructed out of its own echo profile. To find out the particular level measuring echo of the echo profile, echo pulse models and reflection models are used. The average curve is constructed as a result of two methods using fuzzy logic operators. The first method is based on the minimized average curve, the second one makes use of a maximized monotonic decreasing average curve of an echo profile. The Problem of determinating the instant of an echo is analysed using the method of singlelevel or center-of-gravity by varying the duration of transmitted pulse.