Determining object positions on conveyor - using reflex system with fixed first edge position and second edge detection

摘要

A reflex optical system for determining the positions of test pieces, e.g. plate material, on a conveyor scans from edge to edge and establishes the edge positions from the optical system transport spindle characteristics and the output of a built-in angle encoder. It overcomes the usual reflex system difficulties of the effect on the output signal of beam path geometry, useful light spot, ambient temp., surface reflections, differences between specimens, optoelectrical transducer sensitivity etc. The first edge is always placed in the same position. The system scans once across the object and back and the distance or angle transducer outputs corresp. to the four bright/dark or vice-versa transitions are stored. The second edge position is determined from the switching pointsummationsreduced by the initial value.