| 摘要 |
PURPOSE:To improve accuracy of discharging of a specified quantity of flow by a method wherein the discharging device is operated in a supplying time under the mean value of control signals during a discharging period. CONSTITUTION:For example, when the first screw feeder is to be controlled, CPU11 checks at first if the operation is in a supplying period or not at (a-1). When it is a discharging period, the newest weight W is read from A/D converter 10 at (a-2), then the discharging quantity of the feeder per unit time is calculated in reference to a difference between the read weight and the previous weight W, then the value is compared with the desired flow rate F and a control signal for the motor 6 is varied at (a-6) in such a way as the actual discharging quantity approaches the flow rate F at (a-3). Then, the steps (a-4) (a-5) (a-6) are performed for the next supplying period. When the operation is defined in a supplying period at (a-1), the content of (a-6) i.e. the mean value of the control signals for one discharging period is outputted at (a-7) through the control circuit 5 to the motor 6 without performing the steps (a-2) (a-3). In this way, an error from the desired flow rate for the supplying period is reduced and then the discharging of the desired flow rate is made possible. |
