HIGH-PRECISION INJECTION SPEED CONTROLLER

PURPOSE:To control a speed range extending from an ultra-low speed to high speed inexpensively and at high response and high precision, by a method wherein an injection speed detector and an injection speed generator are changed over to those for a high speed/low speed according to a speed control range and further a feed back signal of a speed compensator is changed over appropriately. CONSTITUTION:An injection speed detecting signal e3 which has been changed over to either a high speed or low speed by a logical signal R1 is generated through an injection speed detector 12. A speed compensator 17 generates a speed compensation signal e5 resetting once an integral action by a logical control signal R2 through a logical controller 19 by receiving a deviation signal e4 between a speed instruction signal e2 and injection speed detecting signal e3 of a speed instruction generator 18 and the speed instruction generator 18 makes the speed instruction signal e2 for a high speed or low speed generated by the logical control signal R1 by receiving a speed signal e1 through a speed setting device 20. Dispersion on the speed resulting from individual difference and hysteresis properties of the valve and insufficiency in pressure compensation function which are defects of a proportional solenoid flow control valve can be improved by adding a feedback signal through the speed compensator.