Index: firmware/App/Controllers/LoadCell.c
===================================================================
diff -u -rb5e25e2bf3b87f12f9d1beedf460b5884c8816e9 -ra721c4feab8c89880314070d56224e28d502ac5e
--- firmware/App/Controllers/LoadCell.c	(.../LoadCell.c)	(revision b5e25e2bf3b87f12f9d1beedf460b5884c8816e9)
+++ firmware/App/Controllers/LoadCell.c	(.../LoadCell.c)	(revision a721c4feab8c89880314070d56224e28d502ac5e)
@@ -28,8 +28,10 @@
 
 #define LOAD_CELL_REPORT_PERIOD         (100 / TASK_PRIORITY_INTERVAL)              ///< Broadcast load cell values message every 100 ms.
 #define LOAD_CELL_SAMPLES_TO_AVERAGE    LOAD_CELL_REPORT_PERIOD                     ///< Averaging load cell data over the reporting interval.
-//#define ADC2GRAM                        (0.0894 / LOAD_CELL_SAMPLES_TO_AVERAGE)   ///< Conversion factor from ADC counts to grams.  Division for averaging is folded into this value.
-#define ADC2GRAM                        (0.01183 / LOAD_CELL_SAMPLES_TO_AVERAGE)    ///< Conversion factor from ADC counts to grams.  Division for averaging is folded into this value.
+#define LOAD_CELL_AVERAGE_MULTIPLIER    (1.0 / (F32)LOAD_CELL_SAMPLES_TO_AVERAGE)   ///< Optimization - multiplying is faster than dividing.
+// TODO - gain and offset for load cells should be read from NV Data calibration record.
+#define ADC2GRAM                        0.01126                                     // Conversion factor from ADC counts to grams.  Division for averaging is folded into this value.
+#define LOAD_CELL_ZERO_OFFSET           -237.16                                     // Zero offset (in grams).
 
 // ********** private data **********
 
@@ -94,10 +96,14 @@
     {
         loadCellDataPublicationTimerCounter = 0;
         // calculate load cell average weights
-        filteredLoadCellWeights[ LOAD_CELL_A1 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_A1 ]) * ADC2GRAM;   // division for averaging folded into ADC2GRAM
-        filteredLoadCellWeights[ LOAD_CELL_A2 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_A2 ]) * ADC2GRAM;
-        filteredLoadCellWeights[ LOAD_CELL_B1 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_B1 ]) * ADC2GRAM;
-        filteredLoadCellWeights[ LOAD_CELL_B2 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_B2 ]) * ADC2GRAM;
+        filteredLoadCellWeights[ LOAD_CELL_A1 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_A1 ]) *
+                LOAD_CELL_AVERAGE_MULTIPLIER * ADC2GRAM + LOAD_CELL_ZERO_OFFSET;   // division for averaging folded into ADC2GRAM
+        filteredLoadCellWeights[ LOAD_CELL_A2 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_A2 ]) *
+                LOAD_CELL_AVERAGE_MULTIPLIER * ADC2GRAM + LOAD_CELL_ZERO_OFFSET;
+        filteredLoadCellWeights[ LOAD_CELL_B1 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_B1 ]) *
+                LOAD_CELL_AVERAGE_MULTIPLIER * ADC2GRAM + LOAD_CELL_ZERO_OFFSET;
+        filteredLoadCellWeights[ LOAD_CELL_B2 ].data = (F32)(measuredLoadCellReadingsSum[ LOAD_CELL_B2 ]) *
+                LOAD_CELL_AVERAGE_MULTIPLIER * ADC2GRAM + LOAD_CELL_ZERO_OFFSET;
         // broadcast load cell data
         broadcastLoadCellData( getLoadCellFilteredWeight( LOAD_CELL_A1 ), getLoadCellFilteredWeight( LOAD_CELL_A2 ),
                                getLoadCellFilteredWeight( LOAD_CELL_B1 ), getLoadCellFilteredWeight( LOAD_CELL_B2 ) );