Priority polling example - Johnson Controls - LIT-1201668 - System Integration - LonWorks Integration - 12.0

LonWorks Network Integration with Network Engines and LCS Technical Bulletin

Brand
Johnson Controls
Product name
LonWorks Integration
Document type
Technical Bulletin
Document number
LIT-1201668
Version
12.0
Revision date
2022-08-30
Product status
Active
Language
English

The priority polling process follows a specific pattern where each priority value is selected individually in a sequential manner. The following example moves through two complete cycles, using the priority values in Table 1, Table 2, and Table 3.

Each polling cycle consists of a pattern of six polls that result in the ratios shown in Table 1. The complete polling sequence for the first two cycles is as follows:

  1. First Priority 1 value (A).
  2. Priority 2 value (B).
  3. Priority 1 value (C).
  4. Priority 2 value (D)
  5. Priority 1 value (E).
  6. Priority 3 value (F). (Second Cycle)
  7. Priority 1 value (G).
  8. Priority 2 value (H).
  9. Priority 1 value (I).
  10. Priority 2 value (J).
  11. Priority 1 value (K).
  12. Priority 3 value (L).

The two priority polling cycles described in this document assume that all three priority levels exist. If no objects exist for a particular priority level, then the priority level is skipped, and the cycle continues until the sequence starts again. For a single priority polling cycle, if only one object exists for Priority 1, then that object would be polled three times per priority polling cycle. The same execution occurs for Priority 2 and Priority 3 polled objects, with the exception of the number of times the objects are polled per priority polling cycle. See Table 1, Table 2, and Table 3.

Note: In these tables, numeric value indicates the priority of the objects polled. The sequence of polling is from left to right.
Table 1. Priority Polling Example, Priority 1, Priority 2, and Priority 3 Items
Priority Polling Sequence using Priority 1, Priority 2, and Priority 3 Items (2 cycles)
1 2 1 2 1 3 1 2 1 2 1 3
A B C D E F G H I J K L
Table 2. Priority Polling Example, Priority 1 and Priority 2 Items
Priority Polling Sequence using Priority 1 and Priority 2 Items (2 cycles)
1 2 1 2 1 3 1 2 1 2 1 3
A B C D E - G H I J K -
Table 3. Priority Polling Example, Priority 2 and Priority 3 Items
Priority Polling Sequence using Priority 2 and Priority 3 Items (2 cycles)
1 2 1 2 1 3 1 2 1 2 1 3
- B - D - F - H - J - L
Note: Adding any Priority 1 or 2 polling to points increases your overall scan time.