Process control system with multiple module sequence options

• US 4,910,691 A
• Filed: 09/30/1987
• Issued: 03/20/1990
• Est. Priority Date: 09/30/1987
• Status: Expired due to Term

• Current Assignee: Pavilion Technologies Incorporated (Rockwell Automation, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Skeirik, Richard D.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Black, Thomas G.
• Application Number:
  US07/103,124
• Time in Patent Office: 902 Days
• Field of Search: 364/469, 364/500, 364/513, 364/131, 364/132, 364/148, 364/300, 364/550, 364/138, 364/139
• US Class Current: 706/45
• CPC Class Codes: G05B 13/028 using expert systems only
• CPC Class Codes: G06N 5/04 Inference or reasoning models

Abstract

An integrated system for process control in which a process supervisor procedure (which is preferably the top-level procedure) is configured as a modular software structure, with modules which can be revised by a user at any time without significantly interrupting the operation of the process supervisor. A user can define or redefine modules by editing highly constrained templates, which preferably include module timing and sequencing options including: block becomes active if another specified block has become active; block becomes active if a new value has been entered for a specified data source; block becomes active if a specified time of inactivity has elapsed; and combinations of these.

Claims

1. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller is accordance with signals received from said sensors and in accordance with control parameters;

(3) repeatedly running a process supervisor procedure comprising one or more software modules, for selectively defining one or more of said control parameters for said process controller;

(4) presenting a functional structure to a user, for a new software module and said process supervisor procedure and/or a functional structure corresponding to the user input from which a current software module of said process supervisor procedure was generated, and selectively loading user inputs into said functional structure to be used by said process supervisor procedure;

(5) wherein said functional structure permits the user to define timing and sequencing parameters for respective ones of said software modules which include at least the following options;

(a) become active if another specified software module has become active;

(b) become active if a new value has been, entered for a specified data source;

or

(c) become active if a specified time of inactivity has elapsed.

2. The method of claim 1, wherein said timing and sequencing parameters of step (5) further provide the option of:

become active if a specified external event is found to have occurred.

3. The method of claim 1, wherein said step of loading user inputs to become actively accessed by said process supervisor procedure is only performed after a validation run has been performed.

4. The method of claim 1, wherein said process controller of step (2) uses a cycling step, and said process supervisor procedure of step (3) uses a cycling step.

5. The method of claim 1, wherein said process supervisor procedure of step (3) uses a cycling step, and said process controller of step (2) operates in substantially real-time.

6. The method of claim 1, wherein said functional structure of step (4) comprises the step of presenting itself in a substantially natural language format which is readily understandable by a user who is technically skilled in a predetermined art but who is not necessarily competent in any computer language.

7. The method of claim 1, wherein only restricted portions of said functional structure of step (4) comprises the step of allowing for user alterability.

8. The method of claim 1, wherein said user-alterable portions of said functional structure of step (4) comprise the step of appearing differently to the user than do other portions of said functional structures.

9. The method of claim 1, wherein said process supervisor procedure of step (3) comprises the step of calling on at least one expert subprocedure which includes a knowledge base and inference structure relevant to the process.

10. The method of claim 1, wherein, for each of said control parameters, said process supervisor procedure of step (3) comprises the step of being constrained not to make changes unless the amount of the change would exceed a certain threshold;

and wherein said process supervisor procedure reports every instance where it changes a control parameter.

11. The method of claim 1, wherein for each of said control parameters, said process supervisor procedure of step (3) comprises the step of being constrained not to make changes unless the amount of the change would exceed a certain threshold.

12. The method of claim 1, wherein said process supervisor procedure of step (3) comprises the step of following a feedback control relation including a deadband on respective ones of said control parameters, and wherein said process supervisor procedure follows a feedforward control relation including a deadband on respective ones of said control parameters.

13. The method of claim 1, wherein said process supervisor procedure of step (3) comprises the step of having a maximum iteration period significantly longer than the maximum iteration period of said process controller of step (2).

14. The method of claim 1, wherein said process controller of step (2) uses analog logic for controlling.

15. The method of claim 1, wherein said step (3) of repeatedly running a process supervisor procedure comprises the step of running said process supervisor procedure using a cycling step.

16. The method of claim 1, wherein said software modules of step (4) comprise the step of being defined by respective data definitions, including

pointers to procedures which will carry out a respective function,

and parameters to be passed to said procedures pointed to.

17. The method of claim 1, wherein said software modules of step (4) comprise the step of being defined by respective data definitions, including

pointers to procedures which will carry out a respective function, most of said procedures pointed to corresponding generally to one of a limited number of procedure types,

and, parameters to be passed to said procedures pointed to.

18. The method of claim 1, wherein said software modules of step (4) comprise the step of being defined by respective data definitions, including

pointers to procedures which will carry out a respective function, wherein most of said procedures pointed to correspond generally to one of a limited number of procedure types, and wherein at least some of said procedures which do not correspond generally to any one of said limited number of procedure types,

and, parameters to be passed to said procedures pointed to.

19. The method of claim 1, wherein said control parameters of step (2) comprise the step of including goals of said process controller.

20. The method of claim 1, wherein said functional structure of step (4) comprises the step of including standardized data interface definitions such that the user can specify data having one of plural pre-defined temporal characteristics.

21. The method of claim 1, wherein said functional structure of step (4) comprises the step of including standardized data interface definitions such that the user can specify data having one of a plural pre-defined temporal characteristics, and said pre-defined temporal characteristics include both current values and also time-averaged values.

22. The method of claim 1, wherein said functional structure of step (4) comprises the step of including standardized data interface definitions such that the user can specify data from any one of several different types of control systems having different respective data standards.

23. The method of claim 1, wherein said functional structure of step (4) comprises the step of permitting the user to define timing and sequencing parameters for respective ones of said modules which also include the additional option of:

become active if a specified parameter in a lower-level controller has changed.

24. The method of claim 1, wherein said functional structure of step (4) comprises the step of permitting the user to define timing and sequencing parameters for respective ones of said software modules which also include the additional option of:

become active only on programmatic request.

25. The method of claim 1, wherein said functional structure of step (4) comprises the step of permitting the user to define timing and sequencing parameters for respective ones of said software modules which also includes the additional option of:

become active upon external switching in a specific switch system.

26. The method of claim 1, wherein each said functional structure of step (4) comprises the step of including a standard functional control relationship selected from a very limited set and a pointer to optional user-customized programming.

27. The method of claim 1, wherein said process controller of step (2) and said process supervisor procedure of step (3) comprise processes running on the same computer system.

28. The method of claim 1, wherein said process controller of step (2) and said process supervisor procedure of step (3) are both respective parts of the same software system.