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Title:
METHOD AND APPARATUS FOR PERFORMING DIAGNOSTICS IN CONTROL LOOP OF CONTROL VALVE
Document Type and Number:
Japanese Patent JP2009138947
Kind Code:
A
Abstract:

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.


Inventors:
JUNK KENNETH W
LATWESEN ANNETTE L
Application Number:
JP2009028516A
Publication Date:
June 25, 2009
Filing Date:
February 10, 2009
Export Citation:
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Assignee:
FISHER CONTROLS INT LLC
International Classes:
F15B9/08; F15B13/04; F15B13/044; F15B19/00; G05B23/02; G05D16/20
Domestic Patent References:
JPH09210858A1997-08-15
JPS5914493A1984-01-25
JPH09210858A1997-08-15
JPS5914493A1984-01-25
JPH0246303A1990-02-15
JPH04119275A1992-04-20
Attorney, Agent or Firm:
Patent business corporation Yuko patent office