A control architecture for material handling includes multiple tiers of controllers, such as three. The lowest-level controllers interact directly with sensors and actuators used in the material handling system, such as photo-eyes and motors used with conveyors. The lowest-level controllers receive higher...http://www.google.fr/patents/US7568572?utm_source=gb-gplus-shareBrevet US7568572 - Tiered control architecture for material handling
