From 1b16191c0b39db479dad7c42647d3979d235b1ad Mon Sep 17 00:00:00 2001
From: Peter Kurhajec <61538034+PTKu@users.noreply.github.com>
Date: Wed, 10 Jun 2026 21:13:42 +0200
Subject: [PATCH] fix(core): publish MsgCnt once per cycle to prevent partial
 reads

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.
---
 .../ctrl/src/AxoMessaging/Static/AxoMessenger.st  |  2 +-
 src/core/ctrl/src/AxoObject/AxoObject.st          | 15 ++++++++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/core/ctrl/src/AxoMessaging/Static/AxoMessenger.st b/src/core/ctrl/src/AxoMessaging/Static/AxoMessenger.st
index 295568388..7539a09be 100644
--- a/src/core/ctrl/src/AxoMessaging/Static/AxoMessenger.st
+++ b/src/core/ctrl/src/AxoMessaging/Static/AxoMessenger.st
@@ -84,7 +84,7 @@ NAMESPACE AXOpen.Messaging.Static
             
             
             IF(_lastMessageAggregationCycle <> _context.OpenCycleCount()) THEN
-                THIS.MsgCnt := LINT#0;
+                THIS._msgCntAcc := LINT#0;
             END_IF;   
 
             IF((THIS.MessengerState = eAxoMessengerState#ActiveAlreadyAcknowledged ||
diff --git a/src/core/ctrl/src/AxoObject/AxoObject.st b/src/core/ctrl/src/AxoObject/AxoObject.st
index 125428d0d..1eb1b08a9 100644
--- a/src/core/ctrl/src/AxoObject/AxoObject.st
+++ b/src/core/ctrl/src/AxoObject/AxoObject.st
@@ -96,7 +96,8 @@ NAMESPACE AXOpen.Core
             END_VAR
 
             // We always reset message count upon initialization.
-            THIS.MsgCnt := LINT#0;
+            THIS.MsgCnt := _msgCntAcc;
+            _msgCntAcc := LINT#0; 
 
             IF _isInitialized THEN
                 RETURN;
@@ -146,7 +147,9 @@ NAMESPACE AXOpen.Core
          
 
             // We always reset message count upon initialization.
-            THIS.MsgCnt := LINT#0;
+            THIS.MsgCnt := _msgCntAcc;
+            _msgCntAcc := LINT#0;
+
             IF _isInitialized THEN
                 RETURN;
             END_IF;
@@ -164,9 +167,11 @@ NAMESPACE AXOpen.Core
 
         END_METHOD   
         
-        VAR 
+        VAR PROTECTED
             {#ix-attr:[RenderIgnore()]}            
             _lastMessageAggregationCycle : ULINT;
+             {#ix-attr:[RenderIgnore()]}
+            _msgCntAcc : LINT;
         END_VAR    
         
         ///<summary>
@@ -183,7 +188,7 @@ NAMESPACE AXOpen.Core
             END_IF;
 
             IF(_lastMessageAggregationCycle <> _context.OpenCycleCount()) THEN
-                THIS.MsgCnt := LINT#0;
+                THIS._msgCntAcc := LINT#0;
             END_IF;    
 
             IF(inCount = 0) THEN
@@ -193,7 +198,7 @@ NAMESPACE AXOpen.Core
                 RETURN;
             END_IF;    
             
-            THIS.MsgCnt := inCount + THIS.MsgCnt;    
+            THIS._msgCntAcc := inCount + THIS._msgCntAcc;    
                       
             IF(_parent <> NULL && THIS._parent <> THIS._parent.GetParent()) THEN
                 THIS._parent.AggregateMessage(inCount);