| 摘要 |
PURPOSE:To enable stable feedback control by a method wherein both the control of the measuring circuit of the rotational speed of an injection screw and the feedback operation are performed by a microprocessor. CONSTITUTION:When an injection screw 2 rotates at high speed, because of a short period of pulse signals obtained from a rotary sensor 10, frequency-divided pulse signals sent from a frequency divider 11 is made to be developed in the output of a multiflexer 12 in order to deal with the command signals sent from a microprocessor 17. Even when the signals, obtained by frequency-dividing the signals sent from the rotary sensor 10 with the frequency divider 11, are measured, the time required for measurement is made shorter as compared with a controlling period which is determined by the response speed of a proportional solenoid- operated hydraulic flow control valve 22 and the like, and the measurement by synchronization with the period of applied periodic rotational speed change is possible and consequently the mean rotational speed of the injection screw 2 can be measured in the shortest period of time. Accordingly, the period of periodic rotational speed change due to a vane type coil hydraulic motor 23 becomes shorter than the response time of the proportional solenoid- operated hydraulic flow control valve 22, which regulates the flow rate of working fluid, and consequently the instability of control due to the change of rotational speed as disturbance can be prevented from developing and the stable feedback control is realized.
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