CONTROLLER FOR CONTROL SYSTEM

摘要

PURPOSE:To accelerate the setting time of a control system and to avoid a faulty operation by applying the initial value corresponding to an immediately preceding deviation amount to the output of a PID controller at a time point when a fixed value operation is switched to a feedback operation by the PID controller. CONSTITUTION:When a deviation signal 4 obtained from a set value signal 1 of a controlled system 14 and an output signal 2 through a subtractor 3 is larger than an output signal 18 of a constant generator 17, a comparator 19 connects a changeover switch 12 to the side of an output signal 11 of a constant generator 8 and operates the controlled system 14 by a fixed manipulated variable 13. When the signal 4 is reduced and set within the range of the signal 18, the switch 12 is switched and controlled via a PID controller 6, etc. In this case, the signal 4 obtained immediately before switching is held via a multiplier 21 and a holder 23. Then this output signal is added 9 to the output signal of the controller 6 to define the amount 13. Thus the manipulated variable is changed smoothly when a fixed value operation is switched to a feedback operation by the controller 6.