Index: firmware/App/Modes/ModeFault.c
===================================================================
diff -u -r124b3745d056ac667280cfa0ae1fab8610d44ed2 -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision 124b3745d056ac667280cfa0ae1fab8610d44ed2)
+++ firmware/App/Modes/ModeFault.c	(.../ModeFault.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -77,6 +77,8 @@
         collectTreatmentLogData();
         sendTreatmentLogDataToUI();
     }
+
+    SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_MODE_CHANGE, 0, 0 )
 }
 
 /*********************************************************************//**
Index: firmware/App/Modes/ModeInitPOST.c
===================================================================
diff -u -r8f217e3f4f171dba78c9ac69a3470af442941a89 -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Modes/ModeInitPOST.c	(.../ModeInitPOST.c)	(revision 8f217e3f4f171dba78c9ac69a3470af442941a89)
+++ firmware/App/Modes/ModeInitPOST.c	(.../ModeInitPOST.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -106,6 +106,8 @@
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RESUME, FALSE );
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RINSEBACK, FALSE );
     setAlarmUserActionEnabled( ALARM_USER_ACTION_END_TREATMENT, FALSE );
+
+    SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_MODE_CHANGE, 0, 0 )
 }
 
 /*********************************************************************//**
@@ -131,6 +133,7 @@
     {
         case POST_STATE_START:
             sendUIVersionRequest();
+            SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_STARTUP, 0, 0 )
             postState = POST_STATE_FW_INTEGRITY;
             break;
 
Index: firmware/App/Modes/ModePostTreat.c
===================================================================
diff -u -r1c628bfd5d6414b74b8cbd083f66839888a8236b -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision 1c628bfd5d6414b74b8cbd083f66839888a8236b)
+++ firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -118,6 +118,7 @@
 void transitionToPostTreatmentMode( void )
 {
     initPostTreatmentMode();
+    SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_MODE_CHANGE, 0, HD_POST_TREATMENT_PATIENT_DISCONNECTION_STATE )
 
     // Stop any DG fill that may be in progress from an aborted treatment
     cmdStopDGFill();
Index: firmware/App/Modes/OperationModes.c
===================================================================
diff -u -r8466e63f95f65a3ffb18c3af85ac99328e41167b -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision 8466e63f95f65a3ffb18c3af85ac99328e41167b)
+++ firmware/App/Modes/OperationModes.c	(.../OperationModes.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -317,6 +317,8 @@
  *************************************************************************/
 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 )
     {
Index: firmware/App/Modes/Rinseback.c
===================================================================
diff -u -r028345aae95254cd8ff027d0da533b345da06b4f -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 028345aae95254cd8ff027d0da533b345da06b4f)
+++ firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -1005,8 +1005,9 @@
     {
         RINSEBACK_DATA_PAYLOAD_T data;
         U32 timeout = MAX_RINSEBACK_TIME  / ( MS_PER_SECOND / TASK_GENERAL_INTERVAL );
-        U32 countdown = ( getRinsebackVolume() >= TARGET_RINSEBACK_VOLUME_ML ? MAX_RINSEBACK_TIME : MAX_RINSEBACK_DONE_TIME );
+        U32 countdown = ( getRinsebackVolume() >= TARGET_RINSEBACK_VOLUME_ML ? MAX_RINSEBACK_DONE_TIME : MAX_RINSEBACK_TIME );
 
+        countdown -= rinsebackTimerCtr;
         // Handle countdown past zero
         if ( countdown > MAX_RINSEBACK_DONE_TIME )
         {
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r844f98879b7425c207b58562e623ab960adbc357 -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 844f98879b7425c207b58562e623ab960adbc357)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -321,6 +321,41 @@
 
     return result;
 }
+
+/*********************************************************************//**
+ * @brief
+ * The sendEvent function constructs an HD event message to the UI and
+ * queues the msg for transmit on the appropriate CAN channel.
+ * @details Inputs: none
+ * @details Outputs: HD event msg constructed and queued.
+ * @param event Enumeration of event type that occurred
+ * @param dat1 First data associated with event
+ * @param dat2 Second data associated with event
+ * @return TRUE if msg successfully queued for transmit, FALSE if not
+ *************************************************************************/
+BOOL sendEvent( EVENT_ID_T event, EVENT_DATA_T dat1, EVENT_DATA_T dat2 )
+{
+    BOOL result;
+    MESSAGE_T msg;
+    U08 *payloadPtr = msg.payload;
+    U32 e = (U32)event;
+
+    // Create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_HD_EVENT;
+    msg.hdr.payloadLen = sizeof( U32 ) + sizeof( EVENT_DATA_T ) * 2;
+
+    memcpy( payloadPtr, &e, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &dat1, sizeof( EVENT_DATA_T ) );
+    payloadPtr += sizeof( EVENT_DATA_T );
+    memcpy( payloadPtr, &dat2, sizeof( EVENT_DATA_T ) );
+
+    // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    result = serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_UI, ACK_REQUIRED );
+
+    return result;
+}
 
 /*********************************************************************//**
  * @brief
@@ -1025,7 +1060,7 @@
  * @param newValue parameter change event new data value
  * @return TRUE if msg successfully queued for transmit, FALSE if not
  *************************************************************************/
-BOOL sendTreatmentLogEventData( EVENT_ID_T event, F32 oldValue, F32 newValue )
+BOOL sendTreatmentLogEventData( TX_EVENT_ID_T event, F32 oldValue, F32 newValue )
 {
     MESSAGE_T msg;
     U08 *payloadPtr = msg.payload;
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r844f98879b7425c207b58562e623ab960adbc357 -ra31707ccbf01a1b40f8500bc491dc9c616e7a163
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 844f98879b7425c207b58562e623ab960adbc357)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision a31707ccbf01a1b40f8500bc491dc9c616e7a163)
@@ -92,6 +92,9 @@
 // MSG_ID_HD_DG_POST_RESULT_REQUEST
 BOOL sendDGPOSTResultRequest( void );
 
+// MSG_ID_HD_EVENT
+BOOL sendEvent( EVENT_ID_T event, EVENT_DATA_T dat1, EVENT_DATA_T dat2 );
+
 // MSG_ID_OFF_BUTTON_PRESS
 BOOL sendOffButtonMsgToUI( U08 cmd );
 void handleOffButtonConfirmMsgFromUI( MESSAGE_T *message );
@@ -325,7 +328,7 @@
 BOOL sendTreatmentLogAlarmEventData( ALARM_ID_T alarmID, ALARM_DATA_T almData1, ALARM_DATA_T almData2 );
 
 // MSG_ID_HD_TREATMENT_LOG_EVENT
-BOOL sendTreatmentLogEventData( EVENT_ID_T event, F32 oldValue, F32 newValue );
+BOOL sendTreatmentLogEventData( TX_EVENT_ID_T event, F32 oldValue, F32 newValue );
 
 // *********** public DG command functions **********