AUTO-TUNING SYSTEM FOR PARAMETER OF PID ADJUSTOR

摘要

PURPOSE:To obtain an auto-tuning system for a parameter of an economical PID adjustor by approximating a controlled system to (temporary delay element + idle time element) and finding out P, I and D parameters from the step response. CONSTITUTION:A step signal is applied from a signal generating circuit 13 through a switch S1 by a tuning start command from a command circuit 12. Supposing that the controlled system is (temporary delay element + idle time element), the gain, idle time and time constant of the controlled system are calculated by a gain calculating circuit 20, a multiplying circuit, an integration circuit, the 1st and the 2nd function generating circuits, an idle time/time constant calculating circuit 21 from the step response. A PID patameter calculating circuit 22 calculates the P, I and D parameters and a PID operating circuit 11 executes PID operation and applies the operated result to the controlled system controlled as a manipulated variable MV to control a process variable.