PIEZO-RESISTIVE POSITION INDICATOR

摘要

According to principles of the present invention, a sensor beam provides a linear or non-linear continuous signal to a computer that translates the signal into a valve position reading. In an illustrative embodiment of the invention, a sensor beam incorporating piezo-resistive components forming a Wheatstone bridge abuts a cam mounted on a butterfly valve spindle. Valve movement causes rotation of the cam that, in turn, imparts a bending moment to the sensor beam. This bending moment strains the piezo-resistive components, thereby altering the resistance of the Wheatstone bridge. The computer measures the resistance change using an output signal transmitted by the sensor beam and calculates valve position based thereon.