PV SWITCHING TYPE TWO-DEGREE OF FREEDOM PID CONTROLLER

摘要

PURPOSE: To improve the control delay of normal offset time generated by a target value filter in a ramp block when program control is performed by using two-degree of freedom PID control for applying a set value through the target value filter of first-order delay as an internal set value so that a disturbance response can be improved and overshoot can be suppressed when performing constant value control by using a PID arithmetic part. ;CONSTITUTION: A set value TP at a time point just before the normal offset time from a ramp/constant value switching point in the ramp block of a set value SV is calculated through a switching point calculation part 41 by a switching part 4, a changeover switch 5 is switched to the downside until a value PV exceeds the value TP through a comparator 42, normal PID control is performed as set value SV = internal set value SV1, and the control delay at the ramp block is excluded. When the value PV exceeds the value TP, the changeover switch 5 is switched to the upside by the switching part 4, and the two-degree of freedom PD control to apply the set value SV through a target value filter 3 is started.;COPYRIGHT: (C)1995,JPO