Abstract: A system and method for measuring the position of at least one field producing element (e.g., a magnet) without a direct electrical or physical connection between the field producing element and one or more sensors. In one embodiment, the output from an array of sensors (e.g., Hall Effect sensors) is curve fit using an algorithm having a characteristic bell curve (e.g., curve fit tracking algorithm, center of gravity algorithm, etc.) to determine at least one of an absolute or relative position associated with the field producing element and/or a property associated with the field producing element (e.g., magnetic flux). Another embodiment is directed to detecting errors in one or more of the sensors and excluding the output of the faulty sensors in determining the position associated with the field producing element.

Abstract: In a variable displacement type hydraulic pump/motor assembly including at least one internally movable component, such as a yoke, a swashplate, and the means for moving the swashplate, the improvement includes imparting on this component absolute location indicia markings and the addition of an optical/electronic sensor unit capable of reading such indicia markings fixedly located on a housing of the pump/motor assembly and including an optical read head extending into the housing interior and located at a spaced distance from the indicia markings for reading same, relative to a reference location, and producing a signal indicative of the absolute position of the movable component. The signal can then, in turn, be used for controlling the displacement of the pump/motor assembly. A method for determining the absolute component position is also set forth.