摘要 |
When a reference signal is changed stepwise, a switch is open, and a pneumatic device with a dead time starts being actuated in a PD control mode. After elapse of the dead time, when a controlled variable changes and a position detector produces an output signal, a speed signal which is a differential of a feedback signal changes from a value "0". When a speed detector detects when the speed signal is equal to or greater than a predetermined value, a switching signal is applied to close the switch. After the switch is closed, the pneumatic device is actuated in a PID mode. An overshoot or an oscillation in a controlled variable due to the integration of the dead time in an I control mode can be suppressed.
|