Diagnostics in a process control system which uses multi-variable control techniques

• US 6,615,090 B1
• Filed: 02/07/2000
• Issued: 09/02/2003
• Est. Priority Date: 02/22/1999
• Status: Expired due to Term

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Blevins, Terrence L., Nixon, Mark J., Wojsznis, Wilhelm K.
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US09/499,446
• Time in Patent Office: 1,303 Days
• Field of Search: 700/18-23, 700/86-88, 700/26, 700/27, 700/28, 700/48-53, 714/37, 714/38, 714/46, 714/47, 714/25, 702/183, 702/184, 702/185
• US Class Current: 700/26
• CPC Class Codes: G05B 23/0227 Qualitative history assessment, whereby the type of data acted upon, e.g. waveforms, images or patterns, is not relevant, e.g. rule based assessment; if-then decisions
• CPC Class Codes: G05B 23/027 Alarm generation, e.g. communication protocol; Forms of alarm

Abstract

A diagnostic tool automatically collects and stores data indicative of a variability parameter, a mode parameter, a status parameter and a limit parameter for a multi-variable function block associated with one or more devices or loops within a process control system, processes the collected data to determine which devices, loops or function blocks have problems that result in reduced performance of the process control system, displays a list of detected problems to an operator and then suggests the use of other, more specific diagnostic tools to further pinpoint or correct the problems. When the diagnostic tool recommends and executes a data intensive application as the further diagnostic tool, it automatically configures a controller of the process control network to collect the data needed for such a tool.

Claims

1. A diagnostic tool for use in a process control system having a multiplicity of function blocks wherein one of the multiplicity of function blocks is a multi-variable function block, the diagnostic tool comprising:

a data collection unit configured to communicate with each of the multiplicity of function blocks including the multi-variable function block to receive, on a regular basis during operation of the process control system, data pertaining to a function block operating parameter for each of the multiplicity of function blocks;

a data analyzer that determines a value for the function block operating parameter for each of a number of times during operation of the process control system based on the received function block operating parameter data;

a detector that detects a problem within the process control system based on the determined values of the function block operating parameter; and

an output generator that creates a report indicating the detected problem.

2. The diagnostic tool of claim 1, wherein the function block operating parameter is a variability parameter and wherein the data analyzer determines a variability value associated with the multi-variable function block at each of the number of times based on the collected function block operating parameter data.

3. The diagnostic tool of claim 2, wherein the multi-variable function block has multiple inputs and wherein the data analyzer determines an initial variability index associated with each of the multiple inputs and computes a final variability index as the variability value based on the initial variability indices.

4. The diagnostic tool of claim 3, wherein the detector compares the variability value with a variability limit to detect the problem.

5. The diagnostic tool of claim 3, wherein the function block operating parameter data received from each of the function blocks includes a first variability indication indicative of an actual total standard deviation of a function block parameter and a second variability indication indicative of a capability standard deviation associated with the function block parameter.

6. The diagnostic tool of claim 5, wherein the data analyzer combines the first variability indication with the second variability indication to produce one of the initial variability indices.

7. The diagnostic tool of claim 1, wherein the function block operating parameter is a mode parameter and wherein the data collection unit receives a mode indication from the multi-variable function block.

8. The diagnostic tool of claim 1, wherein the function block operating parameter is a mode parameter, wherein the multi-variable function block has multiple inputs or outputs and wherein the data collection unit receives a mode indication for each of the inputs or outputs of the multi-variable function block.

9. The diagnostic tool of claim 8, wherein the data analyzer determines a final mode value for the multi-variable function block specifying if any one of mode indications is a non-normal mode.

10. The diagnostic tool of claim 1, wherein the function block operating parameter is a status parameter, wherein the multi-variable function block has multiple inputs and wherein the data collection unit receives status indications for each of the inputs or outputs of the multi-variable function block.

11. The diagnostic tool of claim 10, wherein the data analyzer determines a final status value from the status indications indicating if any one of the status indications is a non-normal status.

12. The diagnostic tool of claim 1, wherein the function block operating parameter is limit parameter, wherein the multi-variable function block has multiple inputs or outputs and wherein the data collection unit collects limit indications associated with the inputs or outputs of the multi-variable function block.

13. The diagnostic tool of claim 12, wherein the data analyzer determines a final limit value from the limit indications indicating if any one of the inputs or outputs of the multi-variable function block is at a limit.

14. The diagnostic tool of claim 1, wherein the data collection unit further collects an application state parameter from the multi-variable function block and wherein the detector ignores the function block operating parameter data associated with the multi-variable function block to detect the problem when the multi-variable function block operating parameter data is associated with a time in which the application state parameter was in a first state and the detector uses the function block operating parameter data associated with the multi-variable function block to detect the problem when the function block operating parameter data is associated with a time in which the application state parameter was in a second state.

15. A diagnostic tool for use in a process control system that includes a processor and that uses a multiplicity of function blocks including at least one multi-variable function block to control a process, the diagnostic tool comprising:

a computer readable memory; and

a routine stored on the computer readable memory and adapted to be implemented on the processor, wherein the routine;

collects data pertaining to a function block operating parameter for each of the multiplicity of function blocks including the multi-variable function block on a regular basis during operation of the process;

determines a value for the function block operating parameter for each of a number of times during the operation of the process control system based on the collected function block operating parameter data;

detects a problem within the process control system based on the determined values of the function block operating parameter; and

produces a report that lists the detected problem.

16. The diagnostic tool of claim 15, wherein the function block operating parameter is a variability parameter, wherein the multi-variable function block has multiple inputs and wherein the routine collects variability indications for each of the multiple inputs of the multi-variable function block.

17. The diagnostic tool of claim 16, wherein the routine determines a variability value for the multi-variable function block from the variability indications collected from the multi-variable function blocks and compares the variability value to a variability limit to detect the problem.

18. The diagnostic tool of claim 15, wherein the function block operating parameter is a mode parameter, wherein the multi-variable function block has multiple inputs or outputs and wherein the routine collects mode indications for each of the multiplicity of inputs or outputs of the multi-variable function block.

19. The diagnostic tool of claim 15, wherein the function block operating parameter is a status parameter, wherein the multi-variable function block has multiple inputs or outputs and wherein the routine collects status indications for each of the multiplicity of inputs or outputs of the multi-variable function block.

20. The diagnostic tool of claim 15, wherein the function block operating parameter is limit parameter, wherein the multi-variable function block has multiple inputs or outputs and wherein the routine collects limit indications associated with each of the inputs or outputs of the multi-variable function block.