| 摘要 |
A method of monitoring a Mass Flow Controller (MFC) connected to a pressure chamber for supplying gas to the chamber, which is an unpumped condition, includes cyclically switching the MFC to create successive fill cycles for a test period and measuring the chamber pressure at intervals during the test period. The method is characterised in that the total switch time of the MFC is at least 10% of the fill cycle and in that the method includes obtaining the average of the pressure measurements and comparing them with historical data to determine whether or not the MFC is functioning properly.
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