| 摘要 |
PURPOSE:To enable a stable tension control by moving the upper and lower limitations in a tension control range in parallel to an adequate direction at the time when a tension detection value reaches to the vicinity of the upper and lower limits in the tension control range and by varying a speed reference correction amt. simultaneously. CONSTITUTION:When a tension detection value falls and comes in the lower limit tension detection zone, a tension control lower and upper limits arithmetic unit 25a detects it, outputting a lower limit reaching signal. A tension control upper and lower limits limiting control device 26 measures the output time of a lower limit limiting reaching signal, outputting a tension control forcing signal and dissipating a correction output holding signal forcibly. A speed reference correction amt. is thus increased temporarily. The tension control upper and lower limits limiting control device 26 outputs such upper and lower limits limiting data as moving the upper and lower limits in tension controlling in parallel by an optimum value at the stage of outputting the tension control forcing signal, moving the tension control range downwards. A stabilized tension control is thus executed even if the tension reference is set improperly. |
