| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a self-daignosing method which eliminates the need to newly add hardware for a self-diagnosis. SOLUTION: This method allows a self-diagnosis of the mass flow controller equipped with a pressure control valve 51, a cutoff valve opening and closing the inflow side of the pressure control valve 51, an orifice 53 provided on the outflow side of the pressure control valve 51, a pressure sensor 52 detecting the inflow-side pressure of the orifice 53, and a cutoff valve 6 opening and closing the outflow side of the orifice 53. In this case, while the pressure control valve 51 is fully opened, the cutoff valve 4 is opened and the cutoff valve 6 is closed to fill the duct from the cutoff valve 4 to the cutoff valve 6 with predetermined gas of specific pressure through the cutoff valve 4; and then the cutoff valve 4 is closed and the cutoff valve 6 is opened to let the gas filling the duct flow out and the mass flow controller 5 is diagnosed according to the time up to when the detected pressure of a pressure sensor 52 drops down to predetermined detected pressure by the outflow.</p> |
