Index: firmware/App/Modes/ConsumableSelfTest.c
===================================================================
diff -u -rf760ffc4b10556e5186e9ceb90294262063440ca -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ConsumableSelfTest.c	(.../ConsumableSelfTest.c)	(revision f760ffc4b10556e5186e9ceb90294262063440ca)
+++ firmware/App/Modes/ConsumableSelfTest.c	(.../ConsumableSelfTest.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -158,7 +158,7 @@
 
     if ( priorSubState != currentConsumableSelfTestState )
     {
-        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentConsumableSelfTestState );
+        setCurrentSubState( (U32)currentConsumableSelfTestState );
     }
     // Handle triggered alarm with stop property
     handleConsumableSelfTestStopRequest();
Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -r2cc90affe213bf8485ddacf8da8a4565cb2b8e9a -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 2cc90affe213bf8485ddacf8da8a4565cb2b8e9a)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -719,6 +719,7 @@
 
     if ( priorSubState != currentDialysisState )
     {
+        setCurrentSubState( (U32)currentDialysisState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDialysisState );
     }
     // Publish saline bolus data at set interval (whether we are delivering one or not)
@@ -791,6 +792,7 @@
 
     if ( priorSubState != currentUFState )
     {
+        setCurrentSubState( (U32)currentUFState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentUFState );
     }
 
@@ -837,6 +839,7 @@
 
     if ( priorSubState != currentSalineBolusState )
     {
+        setCurrentSubState( (U32)currentSalineBolusState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentSalineBolusState );
     }
 
Index: firmware/App/Modes/ModeFault.c
===================================================================
diff -u -r1bff8e530735be63ba557b77557a0bc2ac4b37b2 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision 1bff8e530735be63ba557b77557a0bc2ac4b37b2)
+++ firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -74,6 +74,7 @@
     doorClosedRequired( FALSE, FALSE );
     syringeDetectionRequired( FALSE );
     setVenousBubbleDetectionEnabled( FALSE );
+    setCurrentSubState( NO_SUB_STATE );
 
     // Set user alarm recovery actions allowed in this mode
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RESUME, FALSE );
Index: firmware/App/Modes/ModePostTreat.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -153,7 +153,7 @@
     signalBloodPumpHardStop();
     signalDialOutPumpHardStop();
     signalDialInPumpHardStop();
-
+    setCurrentSubState( NO_SUB_STATE );
     collectTreatmentLogData();
 
     exitBloodLeakNormalState();
@@ -550,6 +550,7 @@
 
     if ( priorSubState != currentDrainReservoirState )
     {
+        setCurrentSubState( (U32)currentDrainReservoirState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDrainReservoirState );
     }
 }
Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r1bff8e530735be63ba557b77557a0bc2ac4b37b2 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 1bff8e530735be63ba557b77557a0bc2ac4b37b2)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -221,6 +221,7 @@
     signalDialInPumpHardStop();
     signalDialOutPumpHardStop();
     stopSyringePump();
+    setCurrentSubState( NO_SUB_STATE );
 
     // Set valves to default positions
     setValveAirTrap( STATE_CLOSED );
@@ -938,6 +939,8 @@
  *************************************************************************/
 static HD_PRE_TREATMENT_MODE_STATE_T handlePatientConnectionState( void )
 {
+    HD_PRE_TREATMENT_PAT_CONN_STATE_T priorSubState = currentPreTxPatConnState;
+
     switch ( currentPreTxPatConnState )
     {
         case PRE_TREATMENT_PAT_CONN_WAIT_FOR_UF_VOL_STATE:
@@ -961,6 +964,12 @@
             break;
     }
 
+    if ( priorSubState != currentPreTxPatConnState )
+    {
+        setCurrentSubState( (U32)currentPreTxPatConnState );
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPreTxPatConnState );
+    }
+
     // handle alarms w/ stop property
     if ( TRUE == doesAlarmStatusIndicateStop() )
     {
Index: firmware/App/Modes/ModeService.c
===================================================================
diff -u -r1bff8e530735be63ba557b77557a0bc2ac4b37b2 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModeService.c	(.../ModeService.c)	(revision 1bff8e530735be63ba557b77557a0bc2ac4b37b2)
+++ firmware/App/Modes/ModeService.c	(.../ModeService.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -59,6 +59,7 @@
 {
     doorClosedRequired( FALSE, FALSE );
     syringeDetectionRequired( FALSE );
+    setCurrentSubState( NO_SUB_STATE );
 
     // Set user alarm recovery actions allowed in this mode
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RESUME, FALSE );
Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -147,6 +147,7 @@
     resetDialInPumpRotorCount();
     resetPreLoadStatus();
     setVenousBubbleDetectionEnabled( FALSE );
+    setCurrentSubState( NO_SUB_STATE );
 
     // Set user alarm recovery actions allowed in this mode
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RESUME, FALSE );
@@ -198,6 +199,7 @@
 
     handleDisinfectCancel( stop );
 
+
     // State machine to get DG to prep a reservoir so we can start a treatment
     switch ( currentStandbyState )
     {
Index: firmware/App/Modes/ModeTreatment.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -217,6 +217,7 @@
     initRinseback();
     initTreatmentRecirc();
     initTreatmentEnd();
+    setCurrentSubState( NO_SUB_STATE );
     // Enable venous bubble detection in treatment mode
     setVenousBubbleDetectionEnabled( TRUE );
 
Index: firmware/App/Modes/ModeTreatmentParams.c
===================================================================
diff -u -r730d2eb07acfdf049f6beab646a327d67efbe2ba -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision 730d2eb07acfdf049f6beab646a327d67efbe2ba)
+++ firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -282,6 +282,8 @@
     HD_TREATMENT_PARAMS_MODE_STATE_T priorSubState = currentTreatmentParamsState;
     BOOL stop = isStopButtonPressed();
 
+    setCurrentSubState( NO_SUB_STATE );
+
     if ( TRUE == stop )
     {
         // Ignore stop button in this mode.
@@ -304,11 +306,6 @@
 
     }
 
-    if ( priorSubState != currentTreatmentParamsState )
-    {
-        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentTreatmentParamsState );
-    }
-
     return (U32)currentTreatmentParamsState;
 }
 
Index: firmware/App/Modes/OperationModes.c
===================================================================
diff -u -r19f13e67288117e7f81c1245a75cc6b5f8aaf899 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision 19f13e67288117e7f81c1245a75cc6b5f8aaf899)
+++ firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -61,6 +61,7 @@
 static HD_OP_MODE_T currentMode;                            ///< Current operation mode.
 static U32 currentSubMode;                                  ///< The currently active state of the active mode.
 static U32 broadcastModeIntervalCtr;                        ///< Interval counter used to determine when to broadcast operation mode.  Initialize to 11 to stagger broadcast.
+static U32 currentSubState;
 /// Interval (in task intervals) at which to publish operation mode data to CAN bus.
 static OVERRIDE_U32_T opModePublishInterval = { BROADCAST_HD_OP_MODE_INTERVAL, BROADCAST_HD_OP_MODE_INTERVAL, BROADCAST_HD_OP_MODE_INTERVAL, 0 };
 /// Local structure init for saving confirmation requests
@@ -110,6 +111,7 @@
     lastMode                 = MODE_INIT;
     currentMode              = MODE_INIT;
     currentSubMode           = 0;
+    currentSubState          = 0xFF;
     broadcastModeIntervalCtr = DATA_PUBLISH_COUNTER_START_COUNT;
 
     transitionToNewOperationMode( MODE_INIT );
@@ -136,6 +138,7 @@
 {
     HD_OP_MODE_T newMode;
     U32 priorSubMode = currentSubMode;
+    U32 priorSubState = currentSubState;
 
     // Any new mode requests?
     newMode = arbitrateModeRequest();   // Will return current mode if no pending requests
@@ -209,9 +212,10 @@
             break;
     }   // End switch
 
-    // Send sub-mode change event when appropriate
-    if ( priorSubMode != currentSubMode )
+    // Send operation status event when appropriate
+    if ( lastMode != currentMode || priorSubMode != currentSubMode || priorSubState != currentSubState )
     {
+        sendOperationStatusEvent();
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_MODE_CHANGE, priorSubMode, currentSubMode )
     }
 
@@ -372,8 +376,6 @@
  *************************************************************************/
 static void transitionToNewOperationMode( HD_OP_MODE_T newMode )
 {
-    SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_OP_MODE_CHANGE, lastMode, newMode )
-
     // Setup for new operating mode
     switch ( newMode )
     {
@@ -574,7 +576,30 @@
     return new_id;
 }
 
+void setCurrentSubState( U32 subState )
+{
+    currentSubState = subState;
+}
 
+void sendOperationStatusEvent()
+{
+
+    U32 opData = 0;
+    EVENT_DATA_T dat1;
+    EVENT_DATA_T dat2;
+    dat2.dataType = EVENT_DATA_TYPE_U32;
+    dat2.data.uInt.data = (U32)(d2);
+
+    opData = ( currentMode + ( currentSubMode << SHIFT_8_BITS_FOR_BYTE_SHIFT ) +
+            ( currentSubState << SHIFT_16_BITS_FOR_WORD_SHIFT ) ) & MASK_OFF_U32_MSB;
+
+    dat1.dataType = EVENT_DATA_TYPE_U32;
+    dat1.data.uInt.data = (U32)(opData);
+
+    sendEvent( HD_EVENT_OPERATION_STATUS, dat1, dat2 );
+}
+}
+
 /*************************************************************************
  *                       TEST SUPPORT FUNCTIONS
  *************************************************************************/
Index: firmware/App/Modes/OperationModes.h
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/OperationModes.h	(.../OperationModes.h)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/OperationModes.h	(.../OperationModes.h)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -31,6 +31,8 @@
 
 // ********** public definitions **********
 
+#define NO_SUB_STATE    0xFF ///< value for when submode does not have specific substates and is not applicable.
+
 /// Payload record structure for op mode broadcast message
 typedef struct
 {
@@ -50,6 +52,7 @@
 CONFIRMATION_REQUEST_STATUS_T getConfirmationRequestStatus( GENERIC_CONFIRM_ID_T request_id );      // Get the current confirmation request status
 void setConfirmationRequestStatus( GENERIC_CONFIRM_ID_T request_id, CONFIRMATION_REQUEST_STATUS_T status );  // Set the confirmation request status
 GENERIC_CONFIRM_ID_T addConfirmationRequest( GENERIC_CONFIRM_ID_T request_id, GENERIC_CONFIRM_COMMAND_T request_type, U32 reject_reason );  // Add a new confirmation request
+void setCurrentSubState( U32 subState );                            // Set the current substate.
 
 BOOL testSetOperationMode( HD_OP_MODE_T newMode );                  // Force transition to a given mode (if allowed)
 BOOL testSetOpModePublishIntervalOverride( U32 ms );
Index: firmware/App/Modes/PreTreatmentRecirc.c
===================================================================
diff -u -r2a03f6c87706478406a4962d70f5bae2ccb57728 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision 2a03f6c87706478406a4962d70f5bae2ccb57728)
+++ firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -123,6 +123,7 @@
 
     if ( priorSubState != currentPreTreatmentRecircState )
     {
+        setCurrentSubState( (U32)currentPreTreatmentRecircState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPreTreatmentRecircState );
     }
     // All flags should be handled by now, reset in case flags not handle in current state
Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r1a1f165e033e39d322308cfeac65126c2a006d78 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 1a1f165e033e39d322308cfeac65126c2a006d78)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -288,6 +288,7 @@
 
     if ( priorSubState != currentPrimeState )
     {
+        setCurrentSubState( (U32)currentPrimeState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPrimeState );
     }
 
Index: firmware/App/Modes/Rinseback.c
===================================================================
diff -u -r12708a04ae3365e11180182fc52d005c229a7bc6 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 12708a04ae3365e11180182fc52d005c229a7bc6)
+++ firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -318,6 +318,7 @@
 
     if ( priorSubState != rinsebackState )
     {
+        setCurrentSubState( (U32)rinsebackState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, rinsebackState );
     }
     // Rinseback flags should be handled by now - reset in case not handled by current state
Index: firmware/App/Modes/SampleWater.c
===================================================================
diff -u -r25ede6f944eb53b68c8073404663c99d3ce158b0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/SampleWater.c	(.../SampleWater.c)	(revision 25ede6f944eb53b68c8073404663c99d3ce158b0)
+++ firmware/App/Modes/SampleWater.c	(.../SampleWater.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -117,6 +117,7 @@
 
     if ( priorSubState != currentSampleWaterState )
     {
+        setCurrentSubState( (U32)currentSampleWaterState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentSampleWaterState );
     }
 }
Index: firmware/App/Modes/SelfTests.c
===================================================================
diff -u -r1bff8e530735be63ba557b77557a0bc2ac4b37b2 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/SelfTests.c	(.../SelfTests.c)	(revision 1bff8e530735be63ba557b77557a0bc2ac4b37b2)
+++ firmware/App/Modes/SelfTests.c	(.../SelfTests.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -371,6 +371,7 @@
 
     if ( priorSubState != currentNoCartSelfTestsState )
     {
+        setCurrentSubState( (U32)currentNoCartSelfTestsState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentNoCartSelfTestsState );
     }
     // Publish current self-test time data
@@ -532,6 +533,7 @@
 
     if ( priorSubState != currentDrySelfTestsState )
     {
+        setCurrentSubState( (U32)currentDrySelfTestsState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDrySelfTestsState );
     }
     // Publish current self-test time data
@@ -679,6 +681,7 @@
 
     if ( priorSubState != currentWetSelfTestsState )
     {
+        setCurrentSubState( (U32)currentWetSelfTestsState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentWetSelfTestsState );
     }
 }
Index: firmware/App/Modes/TreatmentEnd.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -211,6 +211,7 @@
 
     if ( priorSubState != treatmentEndState )
     {
+        setCurrentSubState( (U32)treatmentEndState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, treatmentEndState );
     }
     // Re-circulate flags should be handled by now - reset in case not handled by current state
Index: firmware/App/Modes/TreatmentRecirc.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/TreatmentRecirc.c	(.../TreatmentRecirc.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/TreatmentRecirc.c	(.../TreatmentRecirc.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -221,6 +221,7 @@
 
     if ( priorSubState != treatmentRecircState )
     {
+        setCurrentSubState( (U32)treatmentRecircState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, treatmentRecircState );
     }
     // Re-circulate flags should be handled by now - reset in case not handled by current state
Index: firmware/App/Modes/TreatmentStop.c
===================================================================
diff -u -rf1d684e536e7911b356a5d35320c909a1016d3d0 -rce64b7e15824641a6a6465c28eec5d8ec593f110
--- firmware/App/Modes/TreatmentStop.c	(.../TreatmentStop.c)	(revision f1d684e536e7911b356a5d35320c909a1016d3d0)
+++ firmware/App/Modes/TreatmentStop.c	(.../TreatmentStop.c)	(revision ce64b7e15824641a6a6465c28eec5d8ec593f110)
@@ -257,6 +257,7 @@
 
     if ( priorSubState != currentTxStopState )
     {
+        setCurrentSubState( (U32)currentTxStopState );
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentTxStopState );
     }
     // Broadcast treatment stop status