PHASE-LOCKED WEB POSITION SIGNAL USING WEB FIDUCIALS

摘要

Approaches for enhancing web position determination involve phase locking a web movement encoder signal to a sensed web fiducial signal. Fiducials disposed along a longitudinal axis of a substrate are sensed and corresponding sensor signals are generated. An estimated web position is provided by one or more encoder signals. The phase difference between the sensor signals and the encoder signals is calculated and the web position error is determined based on the phase difference. The web position error signal can be fed back to adjust the encoder signals which improves the accuracy of the web position determination.