Index: firmware/App/Controllers/LoadCell.c
===================================================================
diff -u -r497dc26e76083742903525aab1490a6900e94969 -re44aad7a9d5fa48aeaa55c65bd28ad9acde6ce05
--- firmware/App/Controllers/LoadCell.c	(.../LoadCell.c)	(revision 497dc26e76083742903525aab1490a6900e94969)
+++ firmware/App/Controllers/LoadCell.c	(.../LoadCell.c)	(revision e44aad7a9d5fa48aeaa55c65bd28ad9acde6ce05)
@@ -34,31 +34,33 @@
 // TODO check the maximum weight on the load cells in tare. There was 1500 grams limit
 // but it has been removed. Check the load cells data sheet.
 
-#define LOAD_CELL_REPORT_PERIOD             (100 / TASK_PRIORITY_INTERVAL)                  ///< Broadcast load cell values message every 100 ms.
+#define LOAD_CELL_REPORT_PERIOD                     (100 / TASK_PRIORITY_INTERVAL)          ///< Broadcast load cell values message every 100 ms.
 /// Conversion factor from ADC counts to grams.
-static const F32 ADC2GRAM = (0.0894 * 1.1338);
-#define LOAD_CELL_FILTER_ALPHA          0.05                                            ///< Alpha factor for the alpha filter used on load cell readings.
+static const F32 ADC2GRAM =                         (0.0894 * 1.1338);
+#define LOAD_CELL_FILTER_ALPHA                      0.05                                    ///< Alpha factor for the alpha filter used on load cell readings.
 
-#define SIZE_OF_SMALL_LOAD_CELL_AVG         100                                             ///< Small load cell moving average has 100 raw samples @ 10ms intervals (1-second).
-#define SIZE_OF_LARGE_LOAD_CELL_AVG         40                                              ///< Large load cell moving average has 40 samples from small filter @ 100ms intervals (4-second).
+#define SIZE_OF_SMALL_LOAD_CELL_AVG                 100                                     ///< Small load cell moving average has 100 raw samples @ 10ms intervals (1-second).
+#define SIZE_OF_LARGE_LOAD_CELL_AVG                 40                                      ///< Large load cell moving average has 40 samples from small filter @ 100ms intervals (4-second).
 
-#define LOAD_CELL_ADC_ERROR_PERSISTENCE     500                                             ///< Alarm persistence period (in ms) for load cell ADC errors.
+#define LOAD_CELL_ADC_ERROR_PERSISTENCE             500                                     ///< Alarm persistence period (in ms) for load cell ADC errors.
+#define EMPTY_RESERVOIR_WEIGHT_GRAMS                1600                                    ///< Reservoirs empty weight in grams.
+#define MAX_ALLOWED_EXTRA_WEIGHT_BEFORE_TARE_GRAMS  300                                     ///< Max allowed extra weight before tare in grams.
 
 /// Load cell data structure.
 typedef struct
 {
-    U32 rawReading;                                                 ///< Latest raw load cell reading
-    OVERRIDE_F32_T weight;                                          ///< Latest load cell weight
+    U32 rawReading;                                                 ///< Latest raw load cell reading.
+    OVERRIDE_F32_T weight;                                          ///< Latest load cell weight.
     F32 autoCalOffset;                                              ///< Load cell auto-calibration offset
     F32 loadCellVelocity_g_min;                                     ///< Velocity (in g/min) of load cell.
 
-    F32 smallFilterReadings[ SIZE_OF_SMALL_LOAD_CELL_AVG ];                             ///< Load cell samples for small load cell moving average.
-    F32 smallFilterTotal;                                                               ///< Small filter rolling total - used to calc small load cell moving average.
-    F32 smallFilteredWeight;                                                            ///< Load cell small filtered (100 100Hz raw sample) weight.
+    F32 smallFilterReadings[ SIZE_OF_SMALL_LOAD_CELL_AVG ];         ///< Load cell samples for small load cell moving average.
+    F32 smallFilterTotal;                                           ///< Small filter rolling total - used to calc small load cell moving average.
+    F32 smallFilteredWeight;                                        ///< Load cell small filtered (100 100Hz raw sample) weight.
 
-    F32 largeFilterReadings[ SIZE_OF_LARGE_LOAD_CELL_AVG ];                             ///< Load cell samples for large load cell moving average.
-    F32 largeFilterTotal;                                                               ///< Large filter rolling total - used to calc small load cell moving average.
-    F32 largeFilteredWeight;                                                            ///< Load cell large filtered (40 10Hz filtered sample) weight.
+    F32 largeFilterReadings[ SIZE_OF_LARGE_LOAD_CELL_AVG ];         ///< Load cell samples for large load cell moving average.
+    F32 largeFilterTotal;                                           ///< Large filter rolling total - used to calc small load cell moving average.
+    F32 largeFilteredWeight;                                        ///< Load cell large filtered (40 10Hz filtered sample) weight.
 } LOADCELL_T;
 
 // ********** private data **********
@@ -273,8 +275,32 @@
  *************************************************************************/
 void tareLoadCell( LOAD_CELL_ID_T loadCellID )
 {
-    // Add old auto calibration offset to get back to actual weight value
-    loadcells[ loadCellID ].autoCalOffset = ( loadcells[ loadCellID ].smallFilteredWeight + loadcells[ loadCellID ].autoCalOffset );
+    BOOL isWeightOutOfRange = FALSE;
+
+    F32 weight = getLoadCellSmallFilteredWeight( loadCellID );
+
+    // Check if the load cell is being tared for the first time
+    if ( fabs(loadcells[ loadCellID ].autoCalOffset) < NEARLY_ZERO )
+    {
+        // For the first tare, the weight of the reservoir should be considered
+        // The current weight of the load cell should not be greater than the weight of the reservoir + the extra weight
+        F32 deltaWeight = fabs( weight - EMPTY_RESERVOIR_WEIGHT_GRAMS );
+        isWeightOutOfRange = ( deltaWeight > MAX_ALLOWED_EXTRA_WEIGHT_BEFORE_TARE_GRAMS ? TRUE : FALSE );
+    }
+    else
+    {
+        isWeightOutOfRange = ( fabs(weight) > MAX_ALLOWED_EXTRA_WEIGHT_BEFORE_TARE_GRAMS ? TRUE : FALSE );
+    }
+
+    if ( FALSE == isWeightOutOfRange )
+    {
+        // Add old auto calibration offset to get back to actual weight value
+        loadcells[ loadCellID ].autoCalOffset = ( loadcells[ loadCellID ].smallFilteredWeight + loadcells[ loadCellID ].autoCalOffset );
+    }
+    else
+    {
+        SET_ALARM_WITH_1_F32_DATA( ALARM_ID_DG_LOAD_CELLS_TARE_WEIGHT_OUT_OF_RANGE, weight )
+    }
 }
 
 /*********************************************************************//**