JPS6426202A - Pid controller - Google Patents

Abstract

PURPOSE:To eliminate a stationary deviation by multiplying an integral term by a predetermined coefficient according to the value of the deviation, and determining the coefficient optionally when adding the deviation to the integral term. CONSTITUTION:A PID controller 1 processed a proportional term, the integral term, and a differential term by arithmetic parts 4a-4c respectively according to a specific PID arithmetic expression so as to eliminate the deviation en between measurement data (measured value xn) corresponding to the operation state of a system 3 to be controlled measured by a detector 2 and a preset set value x0. A gain block 6 multiplies the sum of them by a specific proportional gain (100/PB) to calculate an output rate yn for the system 3 to be controlled. An integral term arithmetic part 4b which processes the integral term specially uses the value obtained by multiplying the deviation en by a specific integral term control coefficient. Consequently, excellent constant value control which generates no stationary deviation is performed.