Low overhead synchronized activation of functional modules

• US 7,054,399 B1
• Filed: 09/29/2000
• Issued: 05/30/2006
• Est. Priority Date: 09/29/2000
• Status: Expired due to Fees

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.), Rockwell Technologies, LLC
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Hildebran, Bret S., Tenorio, Terence Scott, Sugimoto, Thomas K.
• Primary Examiner(s): Kim, Kevin
• Application Number:
  US09/675,928
• Time in Patent Office: 2,069 Days
• Field of Search: 375/224, 375/226, 375/354, 375/355, 375/356, 375/357, 375/371, 370/222, 370/503, 370/516, 709/208
• US Class Current: 375/355
• CPC Class Codes: G05B 21/02 electric
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04L 7/0033 Correction by delay

Abstract

A system and/or method for synchronizing one or more modules of an industrial controller relative to a common time base. A module may be programmed and/or configured to employ an activation interval for controlling periodic activation for sampling one or more inputs and/or applying data at outputs of the module. The module synchronizes its activation interval based on a coordinated time base signal.

Claims

1. A system for synchronizing a sampling interval at an industrial control module comprising:

a controller for providing to a communications link a coordinated system time base signal having a value indicative of a coordinated system time; and

a module operatively connected to the communications link, the module having an activation interval for controlling periodic activation relative to at least one of an input and an output thereof;

wherein the module is programmed to synchronize the activation interval thereof relative to the coordinated system time base value by delaying activation at the module until the coordinated system time is an integer multiple of the activation interval.

2. The system of claim 1, wherein the activation interval corresponds to a sampling interval for controlling periodic sampling of at least one input of the module.

3. The system of claim 1, wherein the activation interval corresponds to application interval for controlling periodic application of at least one output of the module.

4. The system of claim 1, wherein the communications link includes at least one of a backplane and a network infrastructure.

5. The system of claim 1 further including a plurality of spatially separated modules operatively connected to the communications link, each of the modules having an activation interval for controlling at least one of periodic sampling of at least one input thereof and periodic applying of data to at least one output, each module synchronizing the activation interval thereof relative to the coordinated system time base value so that the activation interval of each module is coordinated with respect to a common time base.

6. The system of claim 1, wherein the activation interval is user-configurable.

7. The system of claim 1, wherein the module is further programmable to disable synchronized activation thereof, when synchronized activation is disabled, the module initiating periodic activation relative to at least one of an input and an output thereof sampling arbitrarily.

8. The system of claim 1, wherein the module is further programmed to periodically resynchronize the activation interval thereof relative to the coordinated system time base value.

9. The system of claim 8, wherein the resynchronization occurs in response to determining that the periodic activation is occurring at a time relative to the coordinated system time base that is outside of an expected range.

10. The system of claim 9, wherein the resynchronization occurs by delaying subsequent activation at the module until coordinated system time is a multiple of the activation interval at the module.

11. A module for use in an industrial controller system comprising:

a communications link for receiving a coordinated system time base signal having a value indicative of a coordinated system time; and

a field side for at least one of sampling input data and applying output data;

wherein the module is programmed to control activation of the field side based on an activation interval value, the module synchronizing the activation interval for the field side relative to the coordinated system time base value by delaying activation of the field side until the coordinated system time has a value that is an integer multiple of the activation interval.

12. The system of claim 11, wherein the activation interval value is a predetermined user-configurable value.

13. The system of claim 11, wherein the field side includes an input, the activation interval defining a sampling interval for the input.

14. The system of claim 11, wherein the field side includes an output, the activation interval defining an application interval for applying data to the output.

15. A system for providing synchronized sampling at an industrial control module comprising:

means for receiving a coordinated system time base signal at the module having a value indicative of a coordinated system time; and

means for synchronizing an activation interval of the module relative to the coordinated system time base value by delaying activation at the module until the coordinated system time is an integer multiple of the activation interval.

16. A method for synchronizing sampling of a module relative to a common time base, the module having an interval for controlling periodic activation relative to at least one of an input and an output thereof, the method comprising the steps of:

receiving a coordinated system time base signal having a value indicative of a coordinated system time; and

synchronizing the activation interval of the module relative to the coordinated system time base value by delaying activation at the module until the coordinated system time is an integer multiple of the activation interval.

17. The method of claim 16, wherein a plurality of modules receive the coordinated system time base signal and synchronize periodic activation thereof relative to the coordinated system time base value so that the periodic activation at each module is coordinated relative to the common time base.

18. The method of claim 16 further including programming the activation interval with a user-selected value.

19. The method of claim 16 further including programming the module to enable or disable the step of synchronizing.

20. The method of claim 16 further including periodically resynchronizing the activation of the module relative to the coordinated system time.

21. The method of claim 20, wherein the resynchronization occurs in response to determining that the periodic activation is occurring at a time relative to the coordinated system time that is outside of an accepted range.

22. The method of claim 21, wherein the step of resynchronizing further includes delaying subsequent activation at the module until the coordinated system time is a multiple of the sampling interval.

23. The method of claim 16, wherein the activation interval is a sampling interval for controlling periodic sampling of at least one input of the module.

24. The method of claim 16, wherein the activation interval is an application interval for control periodic applying of data to at least one output of the module.