Abstract: Apparatus for guiding a strip traveling along a selected path, which apparatus comprises a primary strip position correcting mechanism, such as a payout reel or steering roll that engages a strip at a first location for changing the position of the strip as the strip moves along from the first position to a remote control point. The strip correcting mechanism includes a primary control loop with an actuator for changing the strip position and a feedback control loop that compares the actual strip position with an adjustable reference value to control the position of the moving strip. An edge sensor at the remote control point on the strip path creates an output error signal generally proportional to the deviation of the strip edge at the remote control point from a preselected edge position. This error signal is used for periodically changing the reference value of the position correcting mechanism in the primary loop in accordance with the output error.

Abstract: A sensing device for sensing the position of a continuously moving strip of metal and providing a signal for centering the strip on a given line of movement which has good linearity, good stability, and a time stable output. Segments of a pair of capacitor plates overlap each edge of the strip. These are energized by a square wave signal and the variation in capacity between the plates and the strip caused by lateral movement of the strip is detected by a diode bridge and the resultant signal made available to power apparatus for correcting the position of the web.