Positioning apparatus

摘要

The upper limit value and lower limit value of a control target value are alternately supplied to a single D/A converter in synchronism with a clock, an analog output from the D/A converter is compared with an output from a PBR serving as a position detector, and a motor is driven by the difference voltage, thereby positioning the control object. In this case, control of the moving direction and drive/stop of the motor is performed by a combination between the setting states of the upper and lower limit values and the polarity of the difference voltage, and the switching operation of the selector is stopped during a control operation, thereby making it possible to smoothly perform the control operation at a high speed. The control system can be digitized as a whole by detecting a position by an encoder, and integration of the system can be enhanced, thereby realizing a compact and stable control system.