Method for contactless measurement of speed and/or the length of a string, especially a cable, moving lengthways

摘要

The method involves determining a time period after which a characteristic trait of a diffraction pattern acquired on a receiving surface approximately correlates with a characteristic trait of another diffraction pattern acquired on another receiving surface, in an evaluation device. Advancing speed and advanced length of an extrudate i.e. cable (10), are determined based on the time span and distance between the receiving surfaces and/or representation locations of the characteristic traits.