| 摘要 |
A valve main body including a valve member that opens and closes a valve seat is associated with a fluid pressure driving unit including a pressure-receiving member (piston) that drives the valve member; a valve aperture adjusting unit that sets the aperture of the valve member; an electromagnetic valve unit that supplies and discharges a pilot fluid to and from the fluid pressure driving unit; and a controller that controls the aperture of the valve member. The controller controls the aperture of the valve member by controlling the position of the pressure-receiving member, such that the vacuum chamber attains predetermined target pressure, and monitors a difference between an actual pressure in the vacuum chamber obtained from the pressure sensor and the target pressure, and announces abnormality in the case where the difference deviates from a tolerance range. |
