Evaluation unit of a differential-pressure sensor

US5969258A · kind A · utility

Assignee

• Endress+Hauser Inc. · DE

Inventors

• Peter Gerst · Weil am Rhein, DE
• Karlheinz Banholzer · Eschborn, DE
• Karl Flögel · Schopfheim, DE
• Peter Jung · Balingen, DE

Key dates

• Filing date: Jul 29, 1997
• Grant date: Oct 19, 1999
• Expiry date: Jul 29, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L9/125
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Evaluation unit of a differential-pressure sensor An evaluation unit of a differential-pressure sensor is provided which supplies an output signal which corresponds to a differential pressure (.DELTA.P) which has been corrected with respect to a measuring error due to the static pressure (P.sub.S). The differential-pressure sensor has a capacitive single-chamber differential-pressure measuring cell with two capacitors (4, 5) as sensor element (1), and a temperature sensor (6) is arranged at the sensor element (1). The differential-pressure measured value is corrected by means of a first correction value (.DELTA.K) which is a measure of the static pressure (P.sub.S) at a reference temperature (T.sub.R). This correction value (.DELTA.K) is determined from the difference between a sensor temperature (T.sub.S) determined by means of the temperature sensor (6) and a sum of a temperature discrepancy (T.sub.0) and an internal temperature (T.sub.i) assigned to the sum (.SIGMA.) of the reciprocal values of the capacitances of the two capacitors (4, 5).