Catenary controller

摘要

A catenary-like section of traveling web material hanging between a support point and a stepping motor-driven reel rotating to collect or dispense the material is maintained by regulating the stepping motor rate of rotation in accordance with a control signal output of an ultrasonic transducer operating in the pulse/echo mode to continuously monitor the distance between the low point of the catenary-like section and the transducer. A microcomputer connected between the transducer and the motor accelerates and decelerates the rate of stepping motor rotation in accordance with a predetermined program to maintain the catenary section during changes in the distance between the section low point and the transducer.