| 摘要 |
<p>PURPOSE:To measure the residual amount of a tape with high precision by detecting the revolving angle A of the reel drive disk of one side while either one of the reel drive disks of supply and take-up sides turns by a certain angle H, and measuring the speed of revolution of the disk with a variable related to both reel drive disks of the supply and take-up sides respectively. CONSTITUTION:The disks 1 and 2 are attached coaxially with reels 3 and 4 of the supply and take-up sides respectively, and holes are drilled to these disks with a certain angle respectively. When a switch 9 is turned on, a gate 10 is turned on for the first time at a time point when a phototransistor (PT)8 is turned on, i.e., when a hole 2-1 or 2-2 of the disk 2 passes through. Then a counter 12 is fed to a reset terminal. At the same time, an FF11 is turned on at a moment when the PT8 is turned on, and the ON state of the FF11 is kept until the PT8 is next turned on. The chip enable of the counter 12 is kept on while the FF11 is turned on. Thus the counter 12 works to count the ON/OFF pulses which are so far supplied to a terminal IN consecutively to obtain a pulse number N. The residual amount of the tape is obtained from the number N. The detection of this residual amount of tape can be performed with more improved precision as the tape approaches to the end by increasing H of the take-up side and at the same time decreasing of the supply side respectively.</p> |
