Index: firmware/App/Controllers/DGInterface.c
===================================================================
diff -u -rfee22801cab60be10f4e7c08a1a96645dfdcaf8b -r1017bbc5760a50e20357da1e4f705b3e6157375e
--- firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision fee22801cab60be10f4e7c08a1a96645dfdcaf8b)
+++ firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 1017bbc5760a50e20357da1e4f705b3e6157375e)
@@ -27,11 +27,11 @@
 
 // ********** private definitions **********
 
-#define START_DG_CMD                        TRUE            ///< Parameter for DG start/stop command function.  True = start.
-#define STOP_DG_CMD                         FALSE           ///< Parameter for DG start/stop command function.  False = stop.
+#define START_DG_CMD                        TRUE             ///< Parameter for DG start/stop command function.  True = start.
+#define STOP_DG_CMD                         FALSE            ///< Parameter for DG start/stop command function.  False = stop.
 
-#define DRAIN_RESERVOIR_TO_VOLUME_ML        100             ///< Drain reservoir to this volume (in mL) during treatment.
-#define FILL_RESERVOIR_TO_VOLUME_ML         1500            ///< Fill reservoir to this volume (in mL) during treatment.
+#define DRAIN_RESERVOIR_TO_VOLUME_ML        100              ///< Drain reservoir to this volume (in mL) during treatment.
+#define FILL_RESERVOIR_TO_VOLUME_ML         1500             ///< Fill reservoir to this volume (in mL) during treatment.
 
 /// States of the treatment reservoir management state machine.
 typedef enum TreatmentReservoirMgmt_States
@@ -48,35 +48,34 @@
 // ********** private data **********
 
 // DG status
-static DG_OP_MODE_T dgCurrentOpMode = DG_MODE_INIT;
-static U32 dgSubMode = 0;
-static BOOL dgStarted = FALSE;
-static BOOL dgStartetSet = FALSE;
-static BOOL dgWaterSampled = FALSE;
-static BOOL dgWaterSampledSet = FALSE;
+static DG_OP_MODE_T dgCurrentOpMode = DG_MODE_INIT;          ///< Current DG operation mode.
+static U32 dgSubMode = 0;                                    ///< Current state (sub-mode) of current DG operation mode.
+static BOOL dgStarted = FALSE;                               ///< Flag indicates whether we've commanded the DG to start or stop.
+static BOOL dgTrimmerHeaterOn = FALSE;                       ///< Flag indicates whether we've commanded the DG to start or stop the trimmer heater.
+static BOOL dgWaterSampled = FALSE;                          ///< Flag indicates whether we've commanded the DG to sample water.
 
 // state machine states
 static TREATMENT_RESERVOIR_MGMT_STATE_T currentTrtResMgmtState = TREATMENT_RESERVOIR_MGMT_START_STATE;   ///< Current state of treatment mode reservoir management.
 
 // DG sensor data
-static F32 dgPressures[ NUM_OF_DG_PRESSURE_SENSORS ];
-static F32 dgPrimaryTempSet = 0.0;
-static F32 dgPrimaryTemp = 0.0;
-static F32 dgTrimmerTempSet = 0.0;
-static F32 dgTrimmerTemp = 0.0;
+static F32 dgPressures[ NUM_OF_DG_PRESSURE_SENSORS ];        ///< Latest pressures reported by the DG.
+static F32 dgPrimaryTempSet = 0.0;                           ///< Primary heater target temperature commanded.
+static F32 dgPrimaryTemp = 0.0;                              ///< Latest RO water temperature reported by the DG.
+static F32 dgTrimmerTempSet = 0.0;                           ///< Trimmer heater target temperature commanded.
+static F32 dgTrimmerTemp = 0.0;                              ///< Latest dialysate temperature reported by the DG.
 
 // DG pumps data
-static F32 dgROPumpFlowRateMlMin = 0.0;
-static U32 dgROPumpPressureSetPtPSI = 0;
-static U32 dgDrainPumpSpeedSetPtRPM = 0;
+static F32 dgROPumpFlowRateMlMin = 0.0;                      ///< Latest RO water flow rate reported by the DG.
+static U32 dgROPumpPressureSetPtPSI = 0;                     ///< Latest RO pump target pressure reported by the DG.
+static U32 dgDrainPumpSpeedSetPtRPM = 0;                     ///< Latest Drain pump target speed reported by the DG.
 
 // reservoir data
-static DG_RESERVOIR_ID_T dgActiveReservoir = DG_RESERVOIR_2;
-static DG_RESERVOIR_ID_T dgActiveReservoirSet = DG_RESERVOIR_2;
-static U32 dgReservoirFillVolumeTarget = 0;
-static U32 dgReservoirFillVolumeTargetSet = 0;
-static U32 dgReservoirDrainVolumeTarget = 0;
-static U32 dgReservoirDrainVolumeTargetSet = 0;
+static DG_RESERVOIR_ID_T dgActiveReservoir = DG_RESERVOIR_2;    ///< Latest active reservoir reported by the DG.
+static DG_RESERVOIR_ID_T dgActiveReservoirSet = DG_RESERVOIR_2; ///< Active reservoir commanded.
+static U32 dgReservoirFillVolumeTarget = 0;                  ///< Latest fill-to volume reported by the DG.
+static U32 dgReservoirFillVolumeTargetSet = 0;               ///< Fill-to volume commanded.
+static U32 dgReservoirDrainVolumeTarget = 0;                 ///< Latest drain-to volume reported by the DG.
+static U32 dgReservoirDrainVolumeTargetSet = 0;              ///< Drain-to volume commanded.
 
 // ********** private function prototypes **********
 
@@ -210,6 +209,19 @@
 
 /*********************************************************************//**
  * @brief
+ * The getDGActiveReservoir function gets the current active reservoir.
+ * @details
+ * Inputs : dgActiveReservoirSet
+ * Outputs : none
+ * @return Currently commanded active reservoir.
+ *************************************************************************/
+DG_RESERVOIR_ID_T getDGActiveReservoir( void )
+{
+    return dgActiveReservoirSet;
+}
+
+/*********************************************************************//**
+ * @brief
  * The getDGPressure function gets the latest pressure reported by the DG \n
  * for a given pressure sensor.
  * @details
@@ -439,6 +451,18 @@
     sendDGStartStopCommand( STOP_DG_CMD );
 }
 
+void cmdStartDGTrimmerHeater( void )
+{
+    dgTrimmerHeaterOn = TRUE;
+    sendDGStartStopTrimmerHeaterCommand( START_DG_CMD );
+}
+
+void cmdStopDGTrimmerHeater( void )
+{
+    dgTrimmerHeaterOn = FALSE;
+    sendDGStartStopTrimmerHeaterCommand( STOP_DG_CMD );
+}
+
 /*********************************************************************//**
  * @brief
  * The cmdSetDGActiveReservoir function sends a set active reservoir command \n