Temperature compensation for eddy current sensors

US10684148B2 · kind B2 · utility

Assignee

• epro GmbH · DE

Inventors

• G. Peter Tasche · Gronau, DE
• Michael Schlereth · Wilhermsdorf, DE
• Ulf Overkamp · Gronau, DE

Key dates

• Filing date: Jul 10, 2018
• Grant date: Jun 16, 2020
• Expiry date: Jan 30, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/2006
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for calibrating an eddy current sensor for temperature. Both frequency and one of voltage and current of an oscillator driving the eddy current sensor are measured at a plurality of temperatures and a plurality of target surface distances. Temperature equations are regressed to fit the measured frequency and one of the voltage and the current for each temperature, where the temperature equations have a common number of equivalent factors, and factor equations are regressed for each of the equivalent factors. A gain adjustment and an offset adjustment pair for each of the plurality of temperatures is determined for an oscillator associated with the eddy current sensor, that compensates an output of the eddy current sensor to a standard temperature. A gain equation is regressed to fit the determined gain adjustments, and an offset equation is regressed to fit the determined offset adjustments. The temperature equations, factor equations, gain equation, and offset equation are provided with the eddy current sensor.