To provide a method and apparatus for performing diagnostics in a pneumatic control loop for a control valve.
Pressure sensors 85, 86, 88 and displacement sensors 68, 84 normally provided on a positioner 14 are used for detecting the operating parameters of the control loop. A processor is programmed to receive feedback from the sensors and generate fault signals according to a logic sub-routine. The logic sub-routine may include calculating mass flow of control fluid through outlet ports 52, 54 of a spool valve 26 and comparing with other parameters of the control fluid to detect leaks and blockages in the control loop. Once a fault is detected, the location of the root cause of the fault may be identified by characterizing operating parameters of the control loop at the time of the fault.
LATWESEN ANNETTE L
JPH09210858A | 1997-08-15 | |||
JPS5914493A | 1984-01-25 | |||
JPH09210858A | 1997-08-15 | |||
JPS5914493A | 1984-01-25 | |||
JPH0246303A | 1990-02-15 | |||
JPH04119275A | 1992-04-20 |