| 摘要 |
PROBLEM TO BE SOLVED: To avoid a harmful effect of measurement error due to the difference of pressure sensors and the change of detection sensitivity with time by setting 1st and 2nd setting pressure values based on the measured values of the 1st and 2nd pressure sensors before and after opening 1st and 2nd gate valves. SOLUTION: A controller 150 compares a pressure fluctuation within a transfer chamber 110 before and after opening a gate valve 130a separating atmospheric air from the chamber 110 with differential pressure preliminarily set by an operator between the atmospheric air and the chamber 110. It also compares the pressure fluctuations within both the chambers 110 and a process chamber 120 before and after opening a gate valve 131b separating the chamber 110 from the chamber 120 with differential pressure preliminarily set by the operator between the both chambers 110 and 120. And, when an abnormality takes place in the pressure fluctuation width inside the chamber 110 or 120 when it is opened, a correction is applied to each valve opening set pressure of the valves 130a and 131b.
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