Method for optimizing a link schedule

• US 7,945,682 B2
• Filed: 03/05/2008
• Issued: 05/17/2011
• Est. Priority Date: 10/29/2002
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Hodson, William R.
• Primary Examiner(s): Chankong; Dohm
• Application Number:
  US12/074,662
• Publication Number:
  US 20080229317A1
• Time in Patent Office: 1,168 Days
• Field of Search: 709/228, 709/229, 709/253, 700/1, 700/23, 700/83, 700/7, 700/28, 700/44, 702/188, 702/182
• US Class Current: 709/228
• CPC Class Codes: A01K 15/025 Toys specially adapted for animals
• CPC Class Codes: G06F 15/16 Combinations of two or more digital computers each having at least an arithmetic unit, a program unit and a register, e.g. for a simultaneous processing of several programs coordinating program control therefor G06F9/52; in regulating and control system G05B
• CPC Class Codes: G06F 9/46 Multiprogramming arrangements
• CPC Class Codes: H04L 12/40 Bus networks
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/40208 characterized by the use of a particular bus standard
• CPC Class Codes: H04L 2012/4026 Bus for use in automation systems
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/2475 for supporting traffic characterised by the type of applications
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]

Abstract

A method for improving a link schedule used in a communications network is disclosed. While the method applies generally to networks that operate on a scheduled communications basis, it is described in the context of a Foundation FIELDBUS. The method includes: scheduling sequences and their associated publications according to their relative priority, per application; minimizing delays between certain function blocks, and between certain function blocks and publications; and grouping certain publications. Accordingly, advantages such as latency reduction, schedule length reduction, and improved communications capacity are gained.

Claims

1. A method comprising:

identifying a plurality of function blocks requiring execution;

identifying the function blocks as members of multiple groups;

prioritizing the groups such that each group has a priority;

scheduling the groups containing at least one unscheduled function block for communication on a network to produce a schedule, the groups scheduled in an order based on the priority of the groups; and

initiating execution of the function blocks by one or more processor devices based on the schedule;

wherein identifying the function blocks as members of multiple groups comprises;

following one or more connections in a series of connected function blocks;

adding each unique function block in the series to a first of the groups; and

preventing function blocks in the series that have already been added to the first group from being added to the first group again.

2. The method of claim 1, wherein, if more than one primary connection out of one of the function blocks exists, a group is identified for each of the primary connections.

3. The method of claim 1, wherein prioritizing the groups comprises:

assigning one or more first priorities to one or more groups associated with monitoring an industrial process; and

assigning one or more second priorities to one or more groups associated with controlling the industrial process, the one or more second priorities higher than the one or more first priorities.

4. The method of claim 3, wherein assigning the one or more second priorities comprises:

assigning a higher second priority to a group having a longer execution and publication time and a lower second priority to a group having a shorter execution and publication time.

5. The method of claim 1, wherein scheduling the groups comprises:

adding non-back-calculation publications associated with the function blocks to the schedule, wherein any non-back-calculation publications associated with one of the groups are added to the schedule before any non-back-calculation publications associated with lower priority groups are added.

6. The method of claim 5, wherein scheduling the groups further comprises:

adding back-calculation publications associated with the function blocks to the schedule after the non-back-calculation publications have been added to the schedule, wherein each back-calculation publication is one of;

scheduled immediately adjacent to an already-scheduled publication if possible; and

scheduled where a publication gap is maximized if it is not possible to schedule the back-calculation publication immediately adjacent to an already-scheduled publication.

7. The method of claim 6, wherein scheduling the groups further comprises:

minimizing a delay between (i) a completion of execution of a first function block producing a primary connection output and (ii) an initiation of execution of a second function block directly inputting the primary connection output produced by the first function block;

minimizing a delay between (i) a completion of execution of a third function block producing a non-back-calculation publication and (ii) the non-back-calculation publication produced by the third function block; and

minimizing a delay between (i) an initiation of execution of a fourth function block inputting the non-back-calculation publication and (ii) the inputting of the non-back-calculation publication by the fourth function block.

8. The method of claim 6, wherein scheduling the groups further comprises:

prohibiting execution times of two function blocks associated with a single-application processor device from overlapping; and

prohibiting execution times of any two publications from at least partially overlapping.

9. A method comprising:

identifying a plurality of function blocks requiring execution;

identifying the function blocks as members of multiple groups;

prioritizing the groups such that each group has a priority;

scheduling the groups containing at least one unscheduled function block for communication on a network to produce a schedule, the groups scheduled in an order based on the priority of the groups; and

initiating execution of the function blocks by one or more processor devices based on the schedule;

wherein scheduling the groups comprises;

adding non-back-calculation publications associated with the function blocks to the schedule, wherein any non-back-calculation publications associated with one of the groups are added to the schedule before any non-back-calculation publications associated with lower priority groups are added to the schedule; and

adding back-calculation publications associated with the function blocks to the schedule after the non-back-calculation publications have been added to the schedule.

10. The method of claim 9, wherein each back-calculation publication is one of:

scheduled immediately adjacent to an already-scheduled publication if possible; and

scheduled where a publication gap is maximized if it is not possible to schedule the back-calculation publication immediately adjacent to an already-scheduled publication.

11. The method of claim 9, wherein prioritizing the groups comprises prioritizing the groups based on at least one of:

a group type associated with each group; and

a period length associated with each group.

12. The method of claim 9, wherein prioritizing the groups comprises:

assigning one or more first priorities to one or more groups associated with monitoring an industrial process; and

assigning one or more second priorities to one or more groups associated with controlling the industrial process, the one or more second priorities higher than the one or more first priorities.

13. The method of claim 12, wherein assigning the second priorities to the groups associated with controlling the industrial process comprises:

assigning a higher second priority to a group having a longer execution and publication time and a lower second priority to a group having a shorter execution and publication time.

14. A method comprising:

identifying a plurality of function blocks requiring execution;

identifying the function blocks as members of multiple groups;

prioritizing the groups such that each group has a priority;

scheduling the groups containing at least one unscheduled function block for communication on a network to produce a schedule, the groups scheduled in an order based on the priority of the groups; and

initiating execution of the function blocks by one or more processor devices based on the schedule;

wherein scheduling the groups comprises;

identifying a multi-input function block that has multiple inputs provided by multiple preceding function blocks; and

scheduling execution of the function blocks so that execution of the multiple preceding function blocks coincide with one another.

15. The method of claim 14, wherein the different devices comprise multiple processors.

16. The method of claim 14, wherein scheduling the groups comprises:

adding non-back-calculation publications associated with the function blocks to the schedule, wherein any non-back-calculation publications associated with one of the groups are added to the schedule before any non-back-calculation publications associated with lower priority groups are added.

17. The method of claim 16, wherein scheduling the groups further comprises:

adding back-calculation publications associated with the function blocks to the schedule after the non-back-calculation publications have been added to the schedule, wherein each back-calculation publication is one of;

scheduled immediately adjacent to an already-scheduled publication if possible; and

scheduled where a publication gap is maximized if it is not possible to schedule the back-calculation publication immediately adjacent to an already-scheduled publication.

18. The method of claim 17, wherein scheduling the groups further comprises:

minimizing a delay between (i) a completion of execution of a first function block producing a primary connection output and (ii) an initiation of execution of a second function block directly inputting the primary connection output produced by the first function block;

minimizing a delay between (i) a completion of execution of a third function block producing a non-back-calculation publication and (ii) the non-back-calculation publication produced by the third function block; and

minimizing a delay between (i) an initiation of execution of a fourth function block inputting the non-back-calculation publication and (ii) the inputting of the non-back-calculation publication by the fourth function block.

19. The method of claim 17, wherein scheduling the groups further comprises prohibiting execution times of two function blocks associated with a single one of the devices from overlapping.

20. The method of claim 14, wherein the network comprises a fieldbus.