Digital PID control apparatus

摘要

In the digital PID (P: proportional, I: integral, D: derivative) control apparatus of the present invention, a deviation (en) is obtained from a controlling amount (PVn) of an object to be controlled (8), and a target value (SVn), a velocity type PI control operation (2,3) is carried out on the deviation, a velocity type D control operation (4) is carried out on the deviation or the controlling amount, these velocity type control operation outputs are synthesized, and then converted into a position type manipulation signal, and this signal is supplied to the object to be controlled. The derivation processing unit (4) includes a judgment unit for judging whether K = 2. DELTA t / ( DELTA t + 2 eta .TD) 1 by using a control operation period DELTA t, a derivative time TD and a derivative gain 1 / eta , and the operation unit (11) which carries out a lagged derivative operation by a bilinear transfer method when K 1.