| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum pressure control system capable of avoiding an overshoot in relation to a target vacuum pressure value when vacuum pressure in a vacuum vessel is changed, and a vacuum pressure control system which can correct an error in relationship between the degree of opening of a vacuum-proportion opening and closing valve and a valve-opening command value after the re-assembling of the vacuum-proportion opening and closing valve. SOLUTION: The valve-opening command value, which corresponds with an output value of a potentiometer at the time when the poppet valve element of the vacuum-proportion opening and closing valve is in contact with a valve seat, is determined as a temporary valve-opening command value in S3. Then the new zero point of the degree of opening of the vacuum-proportion opening and closing valve, which has been determined by S11, is a valve-opening command value which has slightly changed from the temporary valve-opening command value obtained by S3. Since the new zero point of the degree of opening of the vacuum-proportion opening and closing valve, which has been determined by S11, falls slightly below a judgement value, it becomes a valve-opening command value immediately after the start of operation of the poppet valve element. COPYRIGHT: (C)2008,JPO&INPIT
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