| 摘要 |
PURPOSE:To improve the responsiveness for temperature rise and to reduce the steady- state deviation and the variation by comparing the deviation of a controlled variable from a set value with a prescribed gain switching value and raising the gain if the deviation exceeds the switching value and setting the gain to a low value in the steady state. CONSTITUTION:At the operation start time, a set value (w) exceeds a controlled variable (y) of a controlled system 6, and a switching signal (s) of a gain switching part 9 is turned off because a difference (w)-(y) is larger than a gain switching value (e). Consequently, power is supplied from a power source 11 to both of heaters H1 and H2. At this time, a manipulated variable (u) is turned on because the difference between the controlled variable (y) and the set value (w) is large. Consequently, the controlled variable (y) approaches the set value (w) in a short time. When the difference (w)-(y) is smaller than the switching value (e), the signal (s) is outputted from the switching part 9, and only the heater H1 is selected. Thus, the rising speed of the controlled variable (y) is lower, and the controlled variable (y) coincides with the set value (w) approximately, and the manipulated variable (u) is controlled to be turned on and off interruptedly. Since the gain is low at this time, the controlled variable (y) has a level approximately equal to the set value (w) without being accompanied with the quick variation.
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