Timeout object for object-oriented, real-time process control system and method of operation thereof

• US 20010018700A1
• Filed: 04/04/2001
• Published: 08/30/2001
• Est. Priority Date: 12/04/1998
• Status: Active Grant

• Current Assignee: Christian R. Thomas, Ellen B. Hawkinson, Thomas A. Clarke, Ziad M. Kaakani
• Original Assignee: Christian R. Thomas, Ellen B. Hawkinson, Thomas A. Clarke, Ziad M. Kaakani
• Inventors: Clarke, Thomas A., Kaakani, Ziad M., Thomas, Christian R., Hawkinson, Ellen B.
• Granted Patent: US 6,687,730 B2
• Time in Patent Office: Days
• US Class Current: 718/102
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/543 User-generated data transfer, e.g. clipboards, dynamic data exchange [DDE], object linking and embedding [OLE]

Abstract

For use in time-limiting a request for information from a client to a resource, a timeout object, a method of operating the same and a real-time process control system employing the timeout object or the method. In one embodiment, the timeout object includes: (1) a client interface that receives, from the client, the request and a time-based parameter and (2) a resource interface that forwards the request to the resource and waits for the information an amount of time that is a function of the time-based parameter, the client interface: (2a) returning the information to the client if the timeout object receives the information within the amount of time and (2b) returning a timeout indicator to the client if the timeout object fails to receive the information within the amount of time.

Claims

1. For use in time-limiting a request for information from a client to a resource, a timeout object, comprising:

a client interface that receives, from said client, said request and a time-based parameter; and

a resource interface that forwards said request to said resource and waits for said information an amount of time that is a function of said time-based parameter, said client interface;

returning said information to said client if said timeout object receives said information within said amount of time, and

returning a timeout indicator to said client if said timeout object fails to receive said information within said amount of time.

2. The timeout object as recited in

claim 1

wherein said timeout indicator indicates whether said resource was available to provide said information.

3. The timeout object as recited in

claim 1

wherein said timeout indicator indicates whether said resource successfully processed said request.

4. The timeout object as recited in

claim 1

wherein said amount of time terminates when said timeout object receives said information from said resource.

5. The timeout object as recited in

claim 1

wherein said client interface is capable of receiving a subsequent request from said client to extend said amount of time.

6. The timeout object as recited in

claim 1

wherein said timeout object is a Component Object Module (COM)-compliant object.

7. The timeout object as recited in

claim 1

wherein said resource is an Object Linking and Embedding (OLE) for Process Control (OPC)-compliant object.

8. A method of time-limiting a request for information from a client to a resource, comprising:

receiving, from said client, said request and a time-based parameter;

forwarding said request to said resource;

waiting for said information an amount of time that is a function of said time-based parameter;

returning said information to said client if said timeout object receives said information within said amount of time; and

returning a timeout indicator to said client if said timeout object fails to receive said information within said amount of time.

9. The method as recited in

claim 8

wherein said timeout indicator indicates whether said resource was available to provide said information.

10. The method as recited in

claim 8

wherein said timeout indicator indicates whether said resource successfully processed said request.

11. The method as recited in

claim 8

wherein said amount of time terminates when said timeout object receives said information from said resource.

12. The method as recited in

claim 8

further comprising receiving a subsequent request from said client to extend said amount of time.

13. The method as recited in

claim 8

wherein said timeout object is a Component Object Module (COM)-compliant object.

14. The method as recited in

claim 8

wherein said resource is an Object Linking and Embedding (OLE) for Process Control (OPC)-compliant object.

15. A real-time process control system, comprising:

a computer system;

a plurality of sensors and controllable devices;

a data bus coupling said computer system to said plurality of sensors and controllable devices, said plurality of sensors and controllable devices representing resources for said computer system;

a client, associated with said computer system and capable of generating a request for information from one of said resources; and

a timeout object for time-limiting said request that includes;

a client interface that receives, from said client, said request and a time-based parameter, and

a resource interface that forwards said request to said one of said resources and waits for said information an amount of time that is a function of said time-based parameter, said client interface;

returning said information to said client if said timeout object receives said information within said amount of time, and

returning a timeout indicator to said client if said timeout object fails to receive said information within said amount of time.

16. The process control system as recited in

claim 15

wherein said timeout indicator indicates whether said one of said resources was available to provide said information.

17. The process control system as recited in

claim 15

wherein said timeout indicator indicates whether said one of said resources successfully processed said request.

18. The process control system as recited in

claim 15

wherein said amount of time terminates when said timeout object receives said information from said one of said resources.

19. The process control system as recited in

claim 15

wherein said client interface is capable of receiving a subsequent request from said client to extend said amount of time.

20. The process control system as recited in

claim 15

wherein said timeout object is a Component Object Module (COM)-compliant object.

21. The process control system as recited in

claim 15

wherein said one of said resources is an Object Linking and Embedding (OLE) for Process Control (OPC)-compliant object.