| 摘要 |
<p>A control valve assembly is capable of diagnosing malfunctions in the control valve assembly and discerning a location of a control fluid leak in the control valve assembly (56). The control valve assembly includes a control valve (22), an actuator (24) and a positioner (56). The actuator includes an actuator vent (63) in an actuator housing, the actuator vent being connected to a flow switch (65). By determining a flow condition through the actuator vent, the positioner determines whether a control fluid leak is located in a control line (57) or in a diaphragm (48).</p> |
