| 摘要 |
A method for controlling the transfer of a flexible web member from a supply reel to a take-up reel, according to which the rotational speeds of the supply reel and the take-up reel are measured and whereby the ratio between these measurements is established independently of the speed and direction of the movement of the web member. The method comprises the steps of storing reference information representing the characteristics of different types of reel and web, releasing the reference information corresponding to the reels and webs used, generating intermediate signals which represent the said ratio combining these intermediate signals with the released reference information and generating output signals in dependence upon the momentary position of the web in relation to one or other ends thereof, and using these output signals for the purpose of visually displaying the position of the web and/or of controlling certain operations of the apparatus. Apparatus is also disclosed comprising angular speed detectors for measuring the rotational speed of each of the reels, and a micro-processor having two counters totalizing the pulse signals generated by the speed detectors and a divider circuit for generating, on receiving a control signal, intermediate signal representing the ratio between the contents of the counters, a memory containing reference information relating to different types of reels and web, and a circuit for combining the intermediate signals with the stored information corresponding to the reels and web used and generating output signals in dependence upon the instantaneous position of the web in relation to one or other of its ends. The output signals are applied to a display device serving to indicate the position of the web member.
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