Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -rd954cab1e721ac955f98feb260d7b978ec14ccab -r1017bbc5760a50e20357da1e4f705b3e6157375e
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision d954cab1e721ac955f98feb260d7b978ec14ccab)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 1017bbc5760a50e20357da1e4f705b3e6157375e)
@@ -16,6 +16,7 @@
 
 #include "BloodFlow.h"
 #include "Buttons.h"
+#include "DGInterface.h"
 #include "Dialysis.h"
 #include "DialInFlow.h"
 #include "DialOutFlow.h"
@@ -42,7 +43,8 @@
 
 static F32 refUFVolume;                                 ///< Current reference volume for ultrafiltration (Where should we be w/r/t ultrafiltration).
 static F32 measUFVolume;                                ///< Current total measured volume for ultrafiltration (Where are we w/r/t ultrafiltration).
-static F32 resStartVolume;                              ///< Reservoir start volume for ultrafiltration (i.e. where did we start with current reservoir).
+static F32 resStartVolume[ NUM_OF_DG_RESERVOIRS ];      ///< Reservoir start volume for ultrafiltration (i.e. where did we start with each reservoir).
+static F32 resFinalVolume[ NUM_OF_DG_RESERVOIRS ];      ///< Reservoir final volume for ultrafiltration (i.e. where did we end after switch with each reservoir).
 static F32 measUFVolumeFromPriorReservoirs;             ///< Current total ultrafiltration volume from previous reservoirs in current treatment.
 
 static U32 uFTimeMS;                                    ///< Current elapsed ultrafiltration time (in ms).  Used for calculating UF reference volume.
@@ -87,7 +89,10 @@
 
     refUFVolume = 0.0;
     measUFVolume = 0.0;
-    resStartVolume = 0.0;
+    resStartVolume[ DG_RESERVOIR_1 ] = 0.0;
+    resStartVolume[ DG_RESERVOIR_2 ] = 0.0;
+    resFinalVolume[ DG_RESERVOIR_1 ] = 0.0;
+    resFinalVolume[ DG_RESERVOIR_2 ] = 0.0;
     measUFVolumeFromPriorReservoirs = 0.0;
 
     uFTimeMS = 0;
@@ -307,7 +312,7 @@
     switch ( currentDialysisState )
     {
         case DIALYSIS_START_STATE:
-            resStartVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );  // always start dialysis w/ reservoir 1
+//            resStartVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );  // should be set by reservoir mgmg state machine now
             currentDialysisState = DIALYSIS_UF_STATE;
             break;
 
@@ -563,14 +568,120 @@
  *************************************************************************/
 static void updateUFVolumes( void )
 {
-    F32 latestResVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );  // TODO - just res 1 for now - add reservoir switching, mgmt later.
+    DG_RESERVOIR_ID_T activeRes = getDGActiveReservoir();
+    F32 latestResVolume;
 
+    // get volume of active reservoir
+    if ( DG_RESERVOIR_1 == activeRes )
+    {
+        latestResVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );
+    }
+    else
+    {
+        latestResVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_2_PRIMARY );
+    }
+
     // calculate UF volumes and provide to dialysate outlet pump controller
     refUFVolume = ( ( (F32)uFTimeMS / MS_PER_SECOND ) / SEC_PER_MIN ) * setUFRate;
-    measUFVolume = measUFVolumeFromPriorReservoirs + ( latestResVolume - resStartVolume );
+    measUFVolume = measUFVolumeFromPriorReservoirs + ( latestResVolume - resStartVolume[ activeRes ] );
+    resFinalVolume[ activeRes ] = latestResVolume;
     setDialOutUFVolumes( refUFVolume, measUFVolume );
 }
 
+/*********************************************************************//**
+ * @brief
+ * The setStartReservoirVolume function updates the baseline volume of the \n
+ * next reservoir to be drawn from before it is switched to (i.e. while it \n
+ * is the inactive reservoir) in order to get a more stable volume.
+ * @details
+ * Inputs : active reservoir, load cell reading from inactive reservoir
+ * Outputs : resStartVolume[]
+ * @return none
+ *************************************************************************/
+void setStartReservoirVolume( void )
+{
+    DG_RESERVOIR_ID_T activeRes = getDGActiveReservoir();
+    DG_RESERVOIR_ID_T inactiveRes;
+    F32 resVolume;
+
+    // get volume of inactive reservoir
+    if ( DG_RESERVOIR_2 == activeRes )
+    {
+        inactiveRes = DG_RESERVOIR_1;
+        resVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );
+    }
+    else
+    {
+        inactiveRes = DG_RESERVOIR_2;
+        resVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_2_PRIMARY );
+    }
+
+    // set starting baseline volume for next reservoir before we switch to it
+    resStartVolume[ inactiveRes ] = resVolume;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The signalReservoirsSwitched function informs this module that the \n
+ * reservoirs have been switched.  The UF volume from prior reservoirs is \n
+ * tentatively added to with a load cell reading of the inactive reservoir.
+ * @details
+ * Inputs : resFinalVolume[], resStartVolume[]
+ * Outputs : measUFVolumeFromPriorReservoirs
+ * @return none
+ *************************************************************************/
+void signalReservoirsSwitched( void )
+{
+    DG_RESERVOIR_ID_T activeRes = getDGActiveReservoir();
+    DG_RESERVOIR_ID_T inactiveRes;
+
+    // get volume of inactive reservoir
+    if ( DG_RESERVOIR_2 == activeRes )
+    {
+        inactiveRes = DG_RESERVOIR_1;
+    }
+    else
+    {
+        inactiveRes = DG_RESERVOIR_2;
+    }
+    // update UF volume from prior reservoirs per tentative res volume for last reservoir
+    measUFVolumeFromPriorReservoirs += ( resFinalVolume[ inactiveRes ] - resStartVolume[ inactiveRes ] );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The setFinalReservoirVolume function updates the UF volume from prior reservoirs \n
+ * with a more stable final reservoir volume of the prior reservoir after it's \n
+ * had a moment to settle.
+ * @details
+ * Inputs : active reservoir, load cell reading from inactive reservoir
+ * Outputs : measUFVolumeFromPriorReservoirs, resFinalVolume[], resStartVolume[]
+ * @return none
+ *************************************************************************/
+void setFinalReservoirVolume( void )
+{
+    DG_RESERVOIR_ID_T activeRes = getDGActiveReservoir();
+    DG_RESERVOIR_ID_T inactiveRes;
+    F32 resVolume;
+
+    // get volume of inactive reservoir
+    if ( DG_RESERVOIR_2 == activeRes )
+    {
+        inactiveRes = DG_RESERVOIR_1;
+        resVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_1_PRIMARY );
+    }
+    else
+    {
+        inactiveRes = DG_RESERVOIR_2;
+        resVolume = getLoadCellWeightInGrams( LOAD_CELL_RESERVOIR_2_PRIMARY );
+    }
+
+    // update UF volume from prior reservoirs per final res volume for last reservoir a bit after we've switched
+    measUFVolumeFromPriorReservoirs -= ( resFinalVolume[ inactiveRes ] - resStartVolume[ inactiveRes ] );
+    resFinalVolume[ inactiveRes ] = resVolume;
+    measUFVolumeFromPriorReservoirs += ( resFinalVolume[ inactiveRes ] - resStartVolume[ inactiveRes ] );
+}
+
 /**@}*/