Patent ID: 6380734
Filing Date: 2002-04-30
Classification: G01B,G01D,G21C,Y02E

Abstract:
An apparatus for verifying the position of a movable member, the movable member being disposed within and movable with respect to a first housing, the apparatus comprising:means for generating a magnetic field within the first housing; first magnetically-responsive means extending a first length in the first housing for sensing the position of the movable member within the first length within the first housing and outputting a first signal indicative of the position of the movable member; second magnetically-responsive means extending a second length less than the first length for sensing the presence of the movable member within the second length and outputting a second signal indicative of the presence of the movable member anywhere within the second length; and means for comparing the first signal with the second signal to verify the position of the moveable member.