Apparatus for determining and/or monitoring a process variable of a medium

US9448097B2 · kind B2 · utility

Assignee

• ENDRESS+HAUSER GMBH+CO.KG · DE

Inventors

• Sergej Lopatin · Lörrach, DE
• Martin Urban · Bad Kötzting, DE

Key dates

• Filing date: Jun 20, 2011
• Grant date: Sep 20, 2016
• Expiry date: Jul 7, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N11/16
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An apparatus for determining and/or monitoring at least one process variable of a medium in a container which comprises a mechanically oscillatable structure, which has at least one oscillation characteristic dependent on the process variable, an electromechanical transducer having at least one piezoelectric element, which excites the structure, by means of an excitation signal supplied to the transducer, to execute mechanical oscillations, and which converts the resulting oscillations of the structure into a received signal, which corresponds to a superpositioning of the excitation signal and a wanted signal representing the oscillation. A reference element in parallel with the transducer and supplied with the excitation signal, via which a reference signal independent of the oscillation and corresponding to the excitation signal is tapped, and an electronics, which, based on the received signal and the reference signal, extracts the wanted signal, and, based on the wanted signal, determines and/or monitors the process variable, wherein, for automatic measuring of temperature of the transducer, the electronics includes a temperature measuring device, which supplies the transducer …