Diagnostics in industrial process control system

• US 7,680,549 B2
• Filed: 04/04/2006
• Issued: 03/16/2010
• Est. Priority Date: 04/04/2005
• Status: Active Grant

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Wehrs, David L., Eryurek, Evren, Kavaklioglu, Kadir, Lattimer, Donald Robert
• Primary Examiner(s): DeCady; Albert
• Assistant Examiner(s): ROBERTSON, DAVID
• Application Number:
  US11/397,319
• Publication Number:
  US 20070010900A1
• Time in Patent Office: 1,442 Days
• Field of Search: 700/26, 700/31, 700/51, 700108-110, 702/81, 702/84, 702/183
• US Class Current: 700/26
• CPC Class Codes: C10G 11/187 Controlling or regulating
• CPC Class Codes: G05B 23/0221 Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods
• CPC Class Codes: G05B 23/024 Quantitative history assessment, e.g. mathematical relationships between available data; Functions therefor; Principal component analysis [PCA]; Partial least square [PLS]; Statistical classifiers, e.g. Bayesian networks, linear regression or correlation analysis; Neural networks

Abstract

A device for diagnosing operation of an industrial process control or monitoring system includes an input configured to receive an input related to a process signal. A first statistical parameter module provides a first statistical parameter output related to a statistical parameter of the process signal. A filter provides a filter output related to a filtered value of the process signal. A second statistical parameter module provides a second statistical parameter output related to a statistical parameter of the filter output. A diagnostic module diagnoses operation of the industrial process based upon the first and second statistical parameters.

Claims

1. A field device for diagnosing operation of an industrial process control or monitoring system, comprising:

an input coupled to the industrial process configured to receive a process signal;

a microprocessor configured to implement;

an enhanced statistical parameter module comprising;

a first statistical parameter module having a first statistical parameter output related to a statistical parameter of the received process signal, wherein the statistical parameter is selected from the group of statistical parameters comprising minimum, maximum, range, mean, root mean squared, standard deviation, Q₂₅, Q₅₀ and Q₇₅;

a filter implementing a plurality of filter algorithms having a filter output related to a filtered value of the received process signal based upon at least one of the filter algorithms;

a second statistical parameter module having a second statistical parameter output related to a statistical parameter of the filter output, the second statistical parameter selected from the group of statistical parameters consisting of minimum, maximum, range, mean, root mean squared, standard deviation, Q₂₅, Q₅₀ and Q₇₅; and

a diagnostic module configured to diagnose operation of the industrial process based upon the first and the second statistical parameters;

an output configured to provide a diagnostic output from diagnostic module.

2. The device of claim 1 wherein the filter output further comprises trimmed data from the input data.

3. The device of claim 2 wherein the filter is configured to remove outliers in the input data.

4. The device of claim 2 wherein the filter is configured to remove data from the input data based upon a comparison of the input data with a moving average.

5. The device of claim 2 wherein the filter is configured to remove data spikes in the input data.

6. The device of claim 1 wherein the filter comprises a low pass filter.

7. The device of claim 1 wherein the filter comprises a band pass filter.

8. The device of claim 1 wherein the filter comprises a high pass filter.

9. The device of claim 1 wherein the filter comprises a custom filter.

10. The device of claim 9 wherein the custom filter is based upon a received parameter.

11. The device of claim 1 including a second input configured to receive a second input related to a second process signal and wherein the diagnostic module diagnoses operation of the industrial process further based upon the second process signal.

12. The device of claim 1 wherein the diagnostic module is configured to diagnose operation of the industrial process further based upon a rule.

13. The device of claim 1 wherein the diagnostic module is configured to diagnose operation of the industrial process further based upon a sensitivity parameter.

14. The device of claim 1 including an input/output connection coupled to a process control loop.

15. The device of claim 14 wherein power for the device is received from a process control loop.

16. The device of claim 1 including a sensor configured to provide an output related to a sensed process variable on a two-wire process control loop.

17. The device of claim 1 including a control element configured to control a process variable and input configured to receive a control signal from a two-wire process control loop.

18. The device of claim 1 wherein the filter includes a plurality of selectable filter functions.

19. The device of claim 1 wherein the filter comprises a difference filter.

20. The device of claim 19 wherein the difference filter is configured to provide a difference in the process variable signal between at least two points in time.

21. The device of claim 20 wherein the at least two points in time comprise two adjacent points in time.

22. A method for diagnosing operation of an industrial process or monitoring system, comprising:

receiving an input in a field device related to a process signal;

calculating with a microprocessor in the field device a first statistical parameter related to a statistical parameter of the process signal, wherein the statistical parameter is selected from the group of statistical parameters comprising of minimum, maximum, range, mean, root mean squared, standard deviation, Q₂₅, Q₅₀ and Q₇₅;

implementing a plurality of filter algorithms and filtering the received process signal based upon at least one of the filter algorithms received to provide a filtered value of the process signal;

calculating with the microprocessor a second statistical parameter based upon the received filtered value of the process signal wherein the statistical parameter is selected from the group of statistical parameters comprising of minimum, maximum, range, mean, root mean squared, standard deviation, Q₂₅, Q₅₀ and Q₇₅; and

diagnosing operation of the industrial process with the microprocessor based upon the first statistical parameter and the second statistical parameter.

23. The method of claim 22 wherein the filter is configured to trim data from the input data.

24. The method of claim 23 wherein the filter is configured to remove outliers in the data.

25. The method of claim 23 wherein the filter is configured to remove data based upon a comparison of the data with a moving average.

26. The method of claim 23 wherein the filter is configured to remove data spikes in the data.

27. The method of claim 22 wherein the filter is selected from the group of filters consisting of low pass, high pass and band pass filter.

28. The method of claim 22 including selecting a filter function in a filter module which includes a plurality of filter functions.

29. The method of claim 22 wherein filtering comprises applying a difference filter.

30. The method of claim 29 wherein the filtering comprises providing a difference in the process signal between two points in time.

31. The method of claim 30 wherein the two points in time comprise adjacent points in time.

32. A field device for diagnosing operation of an industrial process control or monitoring system, comprising:

an input coupled to the industrial process configured to receive a process signal;

a microprocessor configured to implement;

an enhanced statistical parameter module, comprising;

a first statistical parameter module configured to calculate a plurality of statistical parameters and having a first statistical parameter output related to at least one statistical parameter of the received process signal based upon at least one of the plurality of statistical parameters;

a filter having a filter output related to a filtered value of the received process signal, the filtered value comprising a difference in the process signal between at least two points in time;

a second statistical parameter module configured to calculate a plurality of statistical parameters and having a second statistical parameter output related to at least one statistical parameter of the filter output based upon at least one of the plurality of statistical parameters; and

a diagnostic module configured to diagnose operation of the industrial process based upon the first at least one statistical parameter and the second at least one statistical parameter;

an output configured to provide a diagnostic output from diagnostic module.