The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 14, 2006
Filed:
May. 20, 2004
Dietmar Spanke, Steinen, DE;
Manfred Eckert, Todtnau, DE;
Stefan Maier, Rheinfelden, DE;
Holger Steltner, Freiburg, DE;
Dietmar Spanke, Steinen, DE;
Manfred Eckert, Todtnau, DE;
Stefan Maier, Rheinfelden, DE;
Holger Steltner, Freiburg, DE;
Endress & Hauser GmbH & Co. KG, Maulburg, DE;
Abstract
A method for a fill level measurement in accordance with the running time principle, which functions dependably over a long period of time, is provided, having a fill level measuring device with an ultrasonic sensor for transmitting and receiving ultrasound, wherein a repeated check of a resonance frequency of the ultrasonic sensor is performed, in the course of which the ultrasonic sensor is briefly excited to oscillate, following the excitation a signal received by the ultrasonic sensor is picked up, and the actual resonance frequency of the ultrasonic sensor is determined by means of the received signal in that the received signal is digitized and supplied to a digital signal processor, a Fourier transformation of the digitized received signal is performed in the signal processor, a maximum of the Fourier-transformed received signal is determined as a function of the frequency, a frequency at which the maximum occurs is stored as the actual resonance frequency, and during measuring operations the ultrasonic sensor is excited by the digital signal processor by means of the last determined actual resonance frequency.