| 摘要 |
PURPOSE:To vary a duty ratio according to, for example, a polygonal curve for adapting an output rate to the cooling characteristic of a controlled system by obtaining a curve which is adapted to the cooling characteristic of the controlled system as a controlled variable characteristic for cooling among control variables corresponding to the output rate. CONSTITUTION:The deviation (e)(=TM-Tj) between a desired value TM of temperature and the measured value Tj of temperature of the controlled system 1 is calculated and a temperature control part 2 perform PID arithmetic operation to calculate the output rate (m). A microcomputer outputs two kinds of control signals S1 and S2 and a relay ON time pulse value P is found from a constant control period thetac (equivalent to a task period for PID arithmetic) and a relay output period thetaR which is the minimum width of the relay ON time according to the output rate (m) which is calculated from a PID arithmetic expression by the temperature control part 2. The P value (PH) of a heating side is determined according to a linear line when the output rate calculated by the microcomputer is between 0 and 100% and the P value (PC) of a cooling side, on the other hand, is determined according to a curve corresponding to the cooling characteristic of the controlled system 1 when the output rate is between -100 and 0%.
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