JPS55127603A - Control method for physical variable - Google Patents

Abstract

PURPOSE: To secure control over processes by automatically preventing over-control by detecting the deviation of a furnace temperature detection signal from a temperature detection signal from a temperature set signal and by placing a furnace temperature in a steady state by switching when the detection value is within a fixed range.

CONSTITUTION: In control over a physical variable with an initial state increasing like a furnace temperature and a steady state following it, the deviation of a furnace temperature detection signal from temperature detector 7 from a set signal from temperature detector 2 decreases as the furnace temperature approaches the steady state following the initial state, and as it approaches zero, the output of amplifier 3 also approximates zero. Here, approach detector 8 when the deviation is brought within a fixed range inverts its output to send a switching signal, which is received by relay driver 9 to change switch S from the M side, the initial state, over to the A side, the steady state. Consequently, over-control can automatically be prevented to secure control over processes.

COPYRIGHT: (C)1980,JPO&Japio