Linking device in a process control system that allows the formation of a control loop having function blocks in a controller and in field devices

• US 6,618,745 B2
• Filed: 09/10/1999
• Issued: 09/09/2003
• Est. Priority Date: 09/10/1999
• Status: Expired due to Term

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Dienstbier, Steven L., Christensen, Daniel D.
• Primary Examiner(s): EL HADY, NABIL M
• Application Number:
  US09/393,474
• Publication Number:
  US 20030014536A1
• Time in Patent Office: 1,460 Days
• Field of Search: 709/223, 709/224, 709/238, 709/200, 709/201, 702/182, 702/183, 702/188
• US Class Current: 709/201
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/25204 Translate between different communication protocols
• CPC Class Codes: G05B 2219/25274 Communication processor, link interface
• CPC Class Codes: G05B 2219/25428 Field device
• CPC Class Codes: H04L 43/065 related to network devices
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A system and method for interfacing a plurality of field devices which are communicatively coupled on a communication network via a standard communication protocol with a process control system uses a linking device to seamlessly integrate communications between the field devices and a controller within the process control system. The system and method uses the linking device to emulate the communication characteristics of the field devices to link information in field devices with information in a controller of the control system, thereby allowing control loops to include combinations of function blocks from both the field devices and the controller. The linking device uses a link active schedule to monitor substantially all communications on the communication network connecting the field devices and selectively processes and analyzes the monitored communications. The information processed by the linking device, which may include function block information, is automatically routed from a field device to the controller or from the controller to a field device. Other information, such as field device identification information and/or communications diagnostic information, may be collected by the linking device and sent to a user.

Claims

1. A method of interfacing with a plurality of field devices in a process control system having a controller and a user interface communicatively coupled together, a linking device coupled to the controller, and a plurality of field devices communicatively coupled to the linking device via a communication network that uses a first communication protocol, the method comprising:

monitoring substantially all communications on the communication network using the linking device;

selectively processing at least some of the monitored communications in the linking device to obtain first function block information associated with a first function block implemented by one of the plurality of field devices; and

sending the first function block information to a second function block implemented by the controller, wherein the first function block information is sent to the controller via a second communication protocol different than the first communication protocol, wherein the first function block and the second function block are part of a control loop.

2. The method of claim 1, further comprising:

generating third function block information associated with a third function block implemented by the controller;

receiving the third function block information at the linking device via the second communication protocol; and

sending the third function block information to at least a fourth function block via the first communication protocol, wherein the fourth function block is implemented by one of the field devices.

3. The method of claim 1, further comprising selectively processing at least some of the monitored communications in the linking device to produce diagnostic information associated with the communications on the communication network.

4. The method of claim 3, wherein selectively processing at least some of the monitored communications in the linking device to produce diagnostic information includes producing information associated with linking and timing of the communications on the communication network.

5. The method of claim 3, wherein the selectively processing at least some of the monitored communications in the linking device to produce diagnostic information includes producing communication statistics associated with the communications on the communication network.

6. The method of claim 3, further comprising conveying at least some of the diagnostic information to the controller via the second communication protocol.

7. The method of claim 1, further comprising selectively processing at least some of the monitored communications in the linking device to produce identification information associated with one of the field devices.

8. The method of claim 7, further comprising conveying the identification information to a memory in the linking device.

9. The method of claim 7, further comprising conveying the identification information to the process control system via the controller.

10. The method of claim 7, further comprising:

comparing the identification information to commissioning information stored in a memory in the linking device;

determining a discrepancy between the commissioning information and the identification information based on the comparison; and

notifying a user of the discrepancy.

11. The method of claim 10, wherein determining a discrepancy includes determining that a field device has been added to the communication network.

12. The method of claim 10, wherein determining a discrepancy includes determining that one of the field devices is no longer communicating on the communication network.

13. The method of claim 1, further comprising selectively processing at least some of the monitored communications in the linking device to scan view list information in at least one of the field devices.

14. The method of claim 13, further comprising conveying the view list information to the controller.

15. The method of claim 1, wherein the first communication protocol is the Fieldbus protocol.

16. A linking device for interfacing with a plurality of field devices having function blocks communicatively coupled via a communication network that uses a first communication protocol and a controller, the linking device comprising:

a stack communicatively coupled to the communication network that uses the first communication protocol to monitor substantially all communications on the communication network;

a connection manager that uses the communication stack to coordinate communications on the communication network;

a function block data manager that selectively processes at least some of the monitored communications to produce function block information that is associated with a function block implemented by at least one of the field devices; and

a database manager that sends the function block information to the controller via a second communication protocol and receives another function block information associated with another function block implemented by the controller to be sent to said at least one of the field devices as part of a control loop different than the first communication protocol.

17. The device of claim 16, wherein the connection manager receives field device information associated with the controller and sends it to one of the field devices via the communication network.

18. The device of claim 16, further comprising a diagnostic manager that selectively processes at least some of the monitored communications to produce diagnostic information associated with the communications on the communication network.

19. The device of claim 18, wherein the diagnostic information includes information associated with linking and timing of the communications on the communication network.

20. The device of claim 18, wherein the diagnostic information includes communication statistics associated with the communications on the communication network.

21. The device of claim 18, wherein the diagnostic manager is adapted to convey at least some of the diagnostic information to the controller.

22. The device of claim 16, further comprising:

a live list manager that stores a live list identifying the devices attached to the communication network; and

an auto-sense manager that uses the live list to selectively process at least some of the monitored communications to produce identification information associated with at least one of the field devices on the communication network.

23. The device of claim 22, wherein the linking devices includes a memory that stores commissioning information and wherein the auto-sense manager compares the identification information to the commissioning information stored in the linking device memory to determine a discrepancy between the commissioning information and the identification information based on the comparison.

24. The device of claim 23, wherein the linking device notifies a user of the discrepancy.

25. The device of claim 16, wherein the database manager is adapted to retrieve view list information.

26. The device of claim 16, wherein the database manager is adapted to convey the view list information to the controller.

27. The device of claim 16, wherein the first communication protocol is the Fieldbus protocol.

28. A field device interface system for use in a process control system having a controller and a user interface communicatively coupled together, a linking device having a processor therein coupled to the controller, and a plurality of field devices communicatively coupled to the linking device via a communication network that uses a first communication protocol, comprising:

a computer readable memory in the linking device;

a monitoring routine stored on the memory and adapted to be executed by the processor that monitors substantially all communications on the communication network;

a communications processing routine stored on the memory and adapted to be executed by the processor that selectively processes at least some of the monitored communications to produce first function block information associated with a first function block implemented by one of the plurality of field devices; and

a linking routine stored on the memory and adapted to be executed by the processor that sends the first function block information to a second function block implemented by the controller, wherein the first function block information is sent to the controller via a second communication protocol different than the first communication protocol wherein the first function block and the second function block are part of a control loop.

29. The field device interface system of claim 28, wherein the linking routine is further adapted to:

receive third function block information from the controller via the second communication protocol, wherein the third function block information is associated with a third function block implemented by the controller; and

send the third function block information to at least a fourth function block via the first communication protocol, wherein the fourth function block is implemented by one of the field devices.

30. The field device interface system of claim 28, wherein the communications processing routine is further adapted to produce diagnostic

31. The field device interface system of claim 28, wherein the communications processing routine is further adapted to produce diagnostic information associated with the communications on the communication network. information that includes information associated with linking and timing of the communications on the communication network.

32. The field device interface system of claim 31, wherein the communications processing routine is further adapted to produce diagnostic information that includes communication statistics associated with the communications on the communication network.

33. The field device interface system of claim 31, wherein the communications processing routine is further adapted to convey the diagnostic information to the controller.

34. The field device interface system of claim 28, wherein the communications processing routine is further adapted to produce identification information associated with at least one of the field devices.

35. The field device interface system of claim 34, wherein the communications processing routine is further adapted to convey the identification information to the memory in the linking device.

36. The field device interface system of claim 34, wherein the communications processing routine is further adapted to convey the identification information to the controller.

37. The field device interface system of claim 34, wherein the memory includes commissioning information stored therein and further comprising an identification information processing routine stored on the memory and adapted to be executed by the processor that compares the identification information to the commissioning information to determine a discrepancy between the commissioning information and the identification information.

38. The field device interface system of claim 37, wherein the identification information processing routine notifies a user of the discrepancy.

39. The field device interface system of claim 37, wherein the discrepancy indicates that a field device has been added to the communication network.

40. The field device interface system of claim 37, wherein the discrepancy indicates that one of the field devices is no longer communicating on the communication network.

41. The field device interface system of claim 28, wherein the communications processing routine is further adapted to produce view list information.

42. The field device interface system of claim 41, wherein the communications processing routine is further adapted to convey the view list information to the controller.

43. The field device interface system of claim 28, wherein the first communication protocol is the Fieldbus protocol.