Black on black sensing methods

摘要

It is shown that dual detector photoelectric proximity sensors offer the most reliable, cost effective solution for black-on-black sensing, e.g. the detection of a black extrusion on a black conveyor. These sensors combine the desirable characteristics of high excess gain and sharp cut-off. Applications for the sensors abound throughout the tire manufacturing process, including cut-to-length control, splice detection, splice measurement, and strip guidance. Photoelectric proximity sensor fundamentals are reviewed, and factors and requirements involved in designing these sensors are discussed.