PURPOSE: To prevent the number of error amplifiers and the number of error input points from increasing by providing a switching means for control loop disconnection which inputs the output signal of a position holding setter and the control signal of a feedback loop to a servo amplifier separately and independently.
CONSTITUTION: The position holding setter 16 outputs a position holding signal for holding the driving position of an actuator AE and a control loop disconnection switch 8 inputs the output signal of the setter 16 to the servo amplifier 3 separately from and independently of the control signal of the feedback loop. Consequently, when a controlled system is switched, the signal from the setter 16 is inputted to the amplifier 3 independently by the switch 8 to hold the driving position of the AE in a stationary state, thereby disconnecting the control loop from the AE. In this state, the difference between the detection signal of the control loop to be switched and a control set value is read and an adjustment is made by an adjusting means so that the error becomes smaller than a permissible value. Then the control loop is connected to AE by the switch 8, so the control switching is accurately performed without any variation of a load.
KANETO TAKAO
HORIKAWA MIKIO
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