STATE SENSOR SYSTEM AND METHODS

Sensor systems comprising a magnetic circuit (450) comprising a coil (385), a magnet (121), at least one of a ferromagnetic armature plate (130) and a conductive armature plate (130), wherein the at least one of the ferromagnetic armature plate (130) and the conductive armature plate (130) is configured to move axially in response to at least one of the magnet (121) and the coil (385), and a controller (520) configured to apply a known first voltage across the coil and monitor a current through the coil (385) are provided. Methods are also provided.