PURPOSE: To suppress ripple phenomena by converting a control input amount calculated according to control rules based on a digital signal converted by an analog/digital (A/D) converting means and the target value of a controlled variable based on a set function.
CONSTITUTION: A sampler 2 is an A/D converter for converting the analog output of a sensor 3 to a digital amount. A digital computer 1 calculates the control input amount according to the control rules based on the digital input from the sampler 2 and digitally outputs the arithmetic result. At a holder 5 being a D/A converter, the digital output as the arithmetic result of the digital computer 1 is converted to an analog amount so as to drive a controlled system 4. At a hold function setting part 6, a hold function optimum for the applied target input is set to the holder 5 so as to reduce deviation.
WAKUI SHINJI
SAWADA TAKESHI
