| 摘要 |
PURPOSE:To improve accuracy of discharging a specified quantity of flow by a method wherein a control signal of a discharging device is controlled in such a way as discharging capability is set to a certain constant in response to the weight of the discharged item in a weighing hopper. CONSTITUTION:For example, when the first screw feeder is to be controlled, CPU11 at first checks if the operation is in its suplying period, and when the operation is in the discharging period, the updated weight is read from A/D converter 10 and a discharging quantity of feeder per unit time is calculated in reference to a difference between the updated weight and previously read the former weight and then the value is compared with the desired flow rate F. A control signal for a motor 6 is varied through a motor control circuit 5 in such a way as the actual discharging quantity approaches the desired flow rate F and then the newest read weight is checked if it coincides with the predetermined value and the lower limit setting value WL. When the coincidence is detected, the control signal for the motor 6 is stored in the addresses A, B and C in the memory 12. In this way, a control signal for the motor 16 is changed over in response to the weight and a variation in flow rate in the supplying period is improved. |
