fix(core): publish MsgCnt once per cycle to prevent partial reads#1176
Merged
Conversation
S7-1500 WebAPI samples variables at an arbitrary point of the PLC cycle. MsgCnt was reset and re-accumulated live within each cycle, so readers could observe 0 or a partial sum, causing message counts to flicker in the UI. Aggregate into protected _msgCntAcc during the cycle and publish the completed total into MsgCnt at the next cycle's Run/Initialize call. MsgCnt holds the total of the last completed cycle and is written once per cycle, at the cost of one cycle of latency.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
S7-1500 WebAPI samples variables at an arbitrary point of the PLC
cycle. MsgCnt was reset and re-accumulated live within each cycle, so
readers could observe 0 or a partial sum, causing message counts to
flicker in the UI.
Aggregate into protected _msgCntAcc during the cycle and publish the
completed total into MsgCnt at the next cycle's Run/Initialize call.
MsgCnt holds the total of the last completed cycle and is written once
per cycle, at the cost of one cycle of latency.