March 2001 VOL. 18    NO.3 Table of Contents

GUEST EDITORIAL       IVI Extends Its Reach Dany Chiej DA SYSTEMS       Monitoring Your Equipment SmartSignal software may just outperform the standard threshold approach to anomaly detection. The software’s detection engine can monitor an aggregate of correlated sensors from an instrumented system and detect subtle deviations from normal operation. Alan Wilks and David Brochu COVER STORY       The Next Generation of Position Sensing Technology, Part 1: Theory and Design NCAPS is a new noncontact angular position sensor featuring an inductive attenuating coupler that measures phase shift rather than the magnitude of the coupling signal. The original implementations were for a 360° rotary sensor, but the basic concept has also evolved into a linear version. Asad M. Madni et al. FEATURES       Diamagnetic Levitation: The Invisible Force Until recently a laboratory curiosity, diamagnetism has entered the commercial world as part of a hybrid levitation system in which a diamagnetic force provides the necessary control stability and permanent magnets supply the lift. Roger Schmidt Trends in Automation PC-based lean control architecture is rapidly gaining popularity—and improving productivity, efficiency, and reliability along the way. Andrei Moldoveanu Protect Your Circuits PPTC devices provide resettable circuit protection and offer many benefits, especially compared with single-use fuses. Frank Owen DEPARTMENTS       Business Sense Research and Developments Web Picks Literature Showcase Wish List Advertiser Index ABOUT THE COVER The noncontact angular position sensor shown in exploded view on this month's cover features an inductive attenuating coupler developed for motion control applications. Measuring phase shift, rather than the magnitude of the coupling signal, to determine position gives the sensor a high tolerance to mechanical misalignment of the rotating components. Readily mass-producible, the sensors lends itself to automotive steering angle measurements. The design has also been configured as a differential displacement and a linear sensor. Our cover story describes the theory and design of NCAP sensors. Part 1 of a series. (Cover images courtesy of BEI Technologies, Inc.)

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