| 摘要 |
<p>PURPOSE:To control a tape tension in a constant state by absorbing the variance for each set, and to unnecessitate a large capacity ROM. CONSTITUTION:When the set is used, the current I corresponding to a tape winding diameter R for making the tape tension F constant in a microcomputer 11 is calculated by an approximate expression, and the calculated value is supplied to a modulation circuit 12 as a control signal SCi, and a PWM signal corresponding to the control signal SCi is obtained from this modulation circuit 12, then a motor 15 is driven by smoothing the PWM signal by an LPF 13 and supplying it to a constant current drive circuit 14. At the time of adjustment in a production line, constants A-C in the approximate expression optimum for each set are stored in the ROM 21, then the constants A-C are read out from the ROM 21 and used, when the current I is calculated. The tape tension can be controlled in the constant state since the variance for each set is perfectly absorbed. The large capacity ROM is unnecessitated as the current I is obtained by the calculation of the approximate expression.</p> |
