Industrial contactless position sensor

Abstract

A contactless position sensor uses at least a first magnetic flux source on one side of an object, wherein a sensor is responsive to the flux, for providing a sensed signal indicative of varying positions (x) of the first magnetic flux source and the object relative to each other, including a null position (g), wherein the sensed signal is related to the null position and the varying positions according to a relation (1/(g+x))-(1/(g-x)). An additional magnetic flux source can be provided on the other side of the object for providing additional flux sensed by the sensing means, wherein the first and second magnetic flux sources can be arranged to move in unison with respect to the object, or can be stationary while the object moves between them. The second flux source can be made stationary and its flux directed to either the object or to a second object with a fixed distance therebetween. Or, the second flux source can be dispensed with entirely and simulated by a bias signal. The flux sources can be cores with coils wound thereon having the shape of a pot or an E. The sources can be permanent magnets. A simple signal processing technique for linearizing the output can be used in most cases and comprises a simple divider. Certain sensors can even be used without needing a divider in a certain limited linear range.