JPS643703A - Process control system - Google Patents

Abstract

PURPOSE:To realize a process control system that gives no adverse influence to a process at all times by forming a closed loop with a control arithmetic part of a short arithmetic cycle and a process and using the arithmetic result of a fuzzy inference as the set value of the control arithmetic part. CONSTITUTION:A control arithmetic part 2 has an arithmetic cycle shorter than that of a fuzzy inference arithmetic part 1. Then the part 2 and a process 4 form a closed loop. In such a constitution, the state value of the process 4 detected by a sensor 5 is sent to both parts 1 and 2. A fuzzy inference is carried out at a part 1 and the result of this arithmetic is used as the set value of the control arithmetic carried out at the part 2. At the part 2 the input supplied from the part 1 is used as the set value with the input given from the process 4 used as the pass value. Then the part 2 delivers a manipulated variable to a process controller 3 and controls the process 4. Thus the part 2 uses the fuzzy inference result as the set value to always secure the smooth and continuous change of the process state value.