| 摘要 |
PROBLEM TO BE SOLVED: To actualize a valve positioner which can reduce the dead zone of a controlled system and has good operability by calculating a manipulated variable needed to reduce the dead zone and superposing the manipulated variable on a controlled variable that the positioner calculates. SOLUTION: A controller 11 equipped with a control arithmetic means detects whether or not the direction of deviation is a direction wherein a dead zone is generated. When so, it is checked whether or not the quantity of the deviation is large enough to require a Boost function (manipulated variable). When the Boost function is not necessary, a controlled variable (UR=UR) is processed and when the Boost function is necessary, Boost is superposed on a controlled variable UR processing a controlled variable (UR=UR+Boost). When Boost is superposed on the controlled variable UR, the controlled variable UR abruptly increases as shown in the figure since Boost is added and decreases with a descending gradient, and when Boost reaches an unnecessary deviation level, the controlled variable UR, is eliminated.
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