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:
Jan. 19, 1993
Filed:
Dec. 02, 1991
Stephen J Postma, Freeport, IL (US);
Milford M Gesin, Forreston, IL (US);
Nick A Demma, Minneapolis, MN (US);
Paul E Bjork, Forest Lake, MN (US);
Thomas J Wagener, Eden Prairie, MN (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
A proximity sensor is provided with a means for directly measuring parameters of a proximity sensor coil which permit the determination of both the AC and DC resistances of the coil. These parameters are then used to determine a discriminator value magnitude according to a mathematical relationship that has been predetermined through previous analysis of empirical data for the particular coil and application intended for the proximity sensor. In one particular application of the present invention, the rear AC resistance is utilized and is added to the DC resistance after the DC resistance has been mathematically altered by a preselected factor. Alternative embodiments of the present invention can also utilize the imaginary AC component of the impedance either by itself or in conjunction with the rear AC component of the impedance. Whether the real or imaginary AC components of the impedance are used individually or together, the DC resistance is used in the determination of the discriminator value magnitude because of its reliable relationship to the temperature of the coil.