THREAD MONITORING DEVICE, THREAD MONITORING METHOD, THREAD WINDER, AND THREAD MONITORING SYSTEM

摘要

A thread monitoring device 8 is provided with: a light-emitting part 22 which irradiates with light a traveling area where a thread Y travels; a light-receiving part 24 which is disposed at a location facing the light-emitting part 22 across the traveling area, which receives the light having been emitted from the light-emitting part and having been partially blocked by the thread Y, and which outputs a detection signal corresponding to the amount of the light received; and a control unit 26 which detects, on the basis of the detection signal, the state of the thread Y traveling through the travel area. The control unit 26 extracts a prescribed frequency component from the detection signal, and estimates an amount of nap on the thread Y by calculating a standard deviation or an average deviation of the extracted frequency component.