Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -r9944e4f766d9eb4cdf7a5ca7587e3ceca556e106 -r8b73263b38f449dacc0795c67a7cf6240cb79026
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 9944e4f766d9eb4cdf7a5ca7587e3ceca556e106)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 8b73263b38f449dacc0795c67a7cf6240cb79026)
@@ -7,8 +7,8 @@
 *
 * @file    Dialysis.c
 *
-* @author  (last)      Darren Cox
-* @date    (last)      13-May-2022
+* @author  (last)      Dara Navaei
+* @date    (last)      15-Jul-2022
 *
 * @author  (original)  Sean
 * @date    (original)  15-Jan-2020
@@ -65,6 +65,7 @@
 static F32 resCurrVolume[ NUM_OF_DG_RESERVOIRS ];       ///< Reservoir current volume.
 static F32 resLastVolume[ NUM_OF_DG_RESERVOIRS ];       ///< Reservoir previous volume.
 static F32 measUFVolumeFromPriorReservoirs;             ///< Current total ultrafiltration volume from previous reservoirs in current treatment.
+static F32 lcLastSteadyWeight[NUM_OF_LOAD_CELLS];        ///< Load Cell Last Steady Weight for drift test
 
 static U32 uFTimeMS;                                    ///< Current elapsed ultrafiltration time (in ms).  Used for calculating UF reference volume.
 static U32 lastUFTimeStamp;                             ///< HD timer value when we last took stock of ultrafiltration time (so we can determine how much time has elapsed since).
@@ -106,6 +107,7 @@
 static void updateUFVolumes( void );
 
 static void publishSalineBolusData( void );
+static void checkLoadCellsStablePrimaryBackupDriftOutOfRange( DG_RESERVOIR_ID_T reservoirID );
 
 /*********************************************************************//**
  * @brief
@@ -118,6 +120,8 @@
  *************************************************************************/
 void initDialysis( void )
 {
+    U16 i;
+
     currentDialysisState = DIALYSIS_START_STATE;
     currentUFState = UF_START_STATE;
     currentSalineBolusState = SALINE_BOLUS_STATE_IDLE;
@@ -142,6 +146,10 @@
     uFAccuracyCheckTimerCtr = 0;
     lastUFVolumeChecked = 0.0;
 
+    for (i=0; i<NUM_OF_LOAD_CELLS; i++)
+    {
+        lcLastSteadyWeight[i] = LOAD_CELL_ILLEGAL_WEIGHT_VALUE;
+    }
     resetSalineBolus();
 }
 
@@ -186,6 +194,8 @@
 {
     PUMP_CONTROL_MODE_T mode = PUMP_CONTROL_MODE_CLOSED_LOOP;
 
+    doorClosedRequired( TRUE, TRUE );
+
     // Set last UF timestamp so UF ref is resumed from this time
     lastUFTimeStamp = getMSTimerCount();
     // Send dialysate outlet pump latest UF volumes
@@ -1137,6 +1147,8 @@
     // Set starting baseline volume for next reservoir before we switch to it
     resStartVolume[ reservoirID ] = resVolume;
     resFinalVolume[ reservoirID ] = resVolume;
+
+    checkLoadCellsStablePrimaryBackupDriftOutOfRange( reservoirID );
 }
 
 /*********************************************************************//**
@@ -1174,6 +1186,8 @@
     measUFVolumeFromPriorReservoirs -= ( resFinalVolume[ inactiveRes ] - resStartVolume[ inactiveRes ] );
     resFinalVolume[ inactiveRes ] = resVolume;
     measUFVolumeFromPriorReservoirs += ( resFinalVolume[ inactiveRes ] - resStartVolume[ inactiveRes ] );
+
+    checkLoadCellsStablePrimaryBackupDriftOutOfRange( inactiveRes );
 }
 
 /*********************************************************************//**
@@ -1208,4 +1222,53 @@
     return ( resFinalVolume[ reservoirID ] - resStartVolume[ reservoirID ] );
 }
 
+/*********************************************************************//**
+ * @brief
+ * The checkLoadCellsStablePrimaryBackupDriftOutOfRange function checks the
+ * load cells' primary and backup drift when the reservoir level has been stable
+ * for greater than large filter time.
+ * @details Inputs: none
+ * @details Outputs: none
+ * @param reservoirID which is the reservoir ID that is range checked
+ * @return none
+ *************************************************************************/
+static void checkLoadCellsStablePrimaryBackupDriftOutOfRange( DG_RESERVOIR_ID_T reservoirID )
+{
+    F32 loadCellPrimaryWeight, loadCellBackupWeight;
+    F32 loadCellPreviousDrift, loadCellCurrentDrift;
+    F32 driftDiff = 0.0;
+    U16 lcPrimaryIndex, lcBackupIndex;
+
+    if ( DG_RESERVOIR_1 == reservoirID )
+    {
+        lcPrimaryIndex = LOAD_CELL_RESERVOIR_1_PRIMARY;
+        lcBackupIndex = LOAD_CELL_RESERVOIR_1_BACKUP;
+    }
+    else
+    {
+        lcPrimaryIndex = LOAD_CELL_RESERVOIR_2_PRIMARY;
+        lcBackupIndex = LOAD_CELL_RESERVOIR_2_BACKUP;
+    }
+
+    loadCellPrimaryWeight = getReservoirWeightLargeFilter( reservoirID );
+    loadCellBackupWeight  = getReservoirBackupWeightLargeFilter( reservoirID );
+    loadCellCurrentDrift = fabs( loadCellPrimaryWeight - loadCellBackupWeight );
+
+    if ( lcLastSteadyWeight[lcPrimaryIndex] > (LOAD_CELL_ILLEGAL_WEIGHT_VALUE + 1) )
+    {
+        // Weight has been previously saved, ok to test
+        loadCellPreviousDrift = lcLastSteadyWeight[lcPrimaryIndex] - lcLastSteadyWeight[lcBackupIndex];
+        driftDiff = fabs ( loadCellCurrentDrift - loadCellPreviousDrift );
+    }
+    // Save latest reading for next test time
+    lcLastSteadyWeight[lcPrimaryIndex] = loadCellPrimaryWeight;
+    lcLastSteadyWeight[lcBackupIndex]  = loadCellBackupWeight;
+
+    // Check for drift out of range
+    if ( driftDiff > LOAD_CELL_PRIMARY_BACKUP_MAX_ALLOWED_DRIFT_GRAMS )
+    {
+        SET_ALARM_WITH_2_F32_DATA( ALARM_ID_HD_LOAD_CELL_PRIMARY_BACKUP_DRIFT_OUT_OF_RANGE, loadCellCurrentDrift, loadCellPreviousDrift )
+    }
+}
+
 /**@}*/