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:
Sep. 16, 2025
Filed:
Oct. 20, 2020
Ifm Electronic Gmbh, Essen, DE;
Manfred Maurus, Bad Waldsee, DE;
Peter Kimbel, Tettnang, DE;
IFM Electronic GmbH, Essen, DE;
Abstract
The invention relates to a method for monitoring the function of a capacitive pressure measurement cell () which has a measuring capacitor (C) and a reference capacitor (C), to which an internal excitation voltage Uin the form of an alternating square-wave signal is applied. According to the invention, in order to allow the detection of a disturbing influence on the measurement result owing to, in particular, moisture-induced leakage currents, it is proposed that the corresponding voltage values U, Ube sensed from the voltage signal Uduring the falling and/or rising signal curve at least two defined times t, t, and the two pairs of values t; Uand t; Uare used to determine a linear equation U=f(t), wherein the linear equation U=f(t) within the falling or rising signal curve is used to calculate the time tat which the voltage value Uset as a threshold value or switchover point in the comparator-oscillator (SG) is reached, wherein —either the time tis compared with the actual switchover time of the comparator-oscillator (SG) and an error signal is generated in the event of significant deviation, —or the time tis used to define a hypothetical switchover point of the comparator-oscillator (SG), from which a hypothetical working frequency is calculated, and an error signal is generated if there is significant deviation of said hypothetical working frequency from the actual working frequency of the comparator-oscillator (SG).