Index: firmware/App/Controllers/BalancingChamber.c
===================================================================
diff -u -rb2e7c9194acd84783d2bbad64c5720410493e199 -r3f4d88fb2f9531deafba584e32ff2112f333c05c
--- firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision b2e7c9194acd84783d2bbad64c5720410493e199)
+++ firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision 3f4d88fb2f9531deafba584e32ff2112f333c05c)
@@ -19,6 +19,7 @@
 #include "Conductivity.h"
 #include "ConcentratePumps.h"
 #include "DialysatePumps.h"
+#include "DryBiCart.h" // For request setBicarbChamberFillRequested
 #include "FpgaDD.h"
 #include "Heaters.h"
 #include "ModeGenDialysate.h"
@@ -51,6 +52,7 @@
 #define SPENT_DIFF_COUNT_ZERO                       0                                           ///< Zero count difference for spent side fill comparing target count
 #define D48_SPEED_ADJUST_FACTOR                     0.5F                                        ///< D48 speed adjustment factor ( 50% of speed adjustment = 0.5)
 #define D48_SPEED_RANGE_LIMIT                       0.25F                                       ///< D48 speed adjustment range check limit ( D48 speed can vary +/-25% of initial calculated speed)
+#define BICARB_CHAMBER_PERIODIC_FILL_TIME               ( 1 * SEC_PER_MIN * ( MS_PER_SECOND / TASK_GENERAL_INTERVAL ) ) ///< Periodic bicarb chamber fill request 60 sec x 20 = 1200
 #define BAL_CHAMBER_FILL_TIMEOUT_FACTOR             1.5                                         ///< Balancing Chamber fill timeout factor (150% of observed fill count)
 
 /// Payload record structure for balancing chamber switch only request
@@ -68,7 +70,7 @@
 static U32 balChamberValveClosePeriod;                                                          ///< Close balancing chamber valves with the defined time prior switching state.
 static U32 currentBalChamberSwitchingCounter;                                                   ///< Counter (in task interval) to monitor the timing spent during balancing chamber fill/drain operation.
 static BOOL isBalChamberFillInProgress;                                                         ///< Flag indicating balancing chamber fill/drain is in progress.
-static BOOL isPressureStabilizedDuringFill;                                                     ///< Flag indicating that the pressure is stablized due to fill complete.
+static BOOL isPressureStabilizedDuringFill;                                                     ///< Flag indicating that the pressure is stabilized due to fill complete.
 static BAL_CHAMBER_SW_STATE_T balChamberSWState;                                                ///< Current balancing chamber switching state ( state 1 or state 2).
 static U32 balChamberDataPublicationTimerCounter;                                               ///< Used to schedule balancing chamber data publication to CAN bus.
 static U32 balChamberFillPressureDropCounter;                                                   ///< Counter to check balancing chamber valves opened and there by pressure drop is seen.
@@ -86,6 +88,8 @@
 static U32 balChamberFillTimeoutCount;                                                          ///< Timeout count (in task interval) to detect BC fill timeout.
 static S32 diffSpentFillCompleteCount;                                                          ///< Difference between spent target fill to actual fill count
 static BOOL isSpentFillComplete;                                                                ///< Flag indicating spent side fill complete.
+//TODO: remove later once level sensor working
+static U32 bicarbChamberPeriodicFillCounter;  
 
 // ********** private function prototypes **********
 
@@ -145,6 +149,8 @@
     balChamberFillTimeoutCount                  = 0;
     diffSpentFillCompleteCount                  = 0;
     isSpentFillComplete                         = FALSE;
+    //TODO:remove once level sensor working
+    bicarbChamberPeriodicFillCounter            = 0;
 }
 
 /*********************************************************************//**
@@ -216,7 +222,23 @@
     currentBalChamberSwitchingCounter += 1;
     currentBalChamberFillCounter += 1;
 
-    // execute current balancing chamber exec state
+    if ( getTestConfigStatus( TEST_CONFIG_DD_ENABLE_DRY_BICARB ) == TRUE )
+    {
+        // Increment counter for dry bicarb chamber fill
+        bicarbChamberPeriodicFillCounter += 1;
+        // Fill bicarb chamber once every 60secs.
+        if ( bicarbChamberPeriodicFillCounter >= BICARB_CHAMBER_PERIODIC_FILL_TIME )
+        {
+            if ( FALSE == setBicarbChamberFillRequested() )
+            {
+                // TODO
+                //drybicart state machines are combined and so this is not an issue in future
+                //set alarm ?
+            }
+            bicarbChamberPeriodicFillCounter = 0;
+        }
+    }
+
     switch ( balChamberExecState )
     {
         case BAL_CHAMBER_STATE_START:
@@ -1124,7 +1146,7 @@
 {
     BOOL result = FALSE;
 
-    // Verify tester has logged in with TD
+    // Verify tester has logged in with DD
     if ( TRUE == isTestingActivated() )
     {
         // Verify payload length is valid