Index: firmware/App/Services/DDInterface.c
===================================================================
diff -u -re9e339870c5ed01230963f00d400331ab879c91f -re7e2fef9fda6c6e876f7aba1c8f837d8aa713392
--- firmware/App/Services/DDInterface.c	(.../DDInterface.c)	(revision e9e339870c5ed01230963f00d400331ab879c91f)
+++ firmware/App/Services/DDInterface.c	(.../DDInterface.c)	(revision e7e2fef9fda6c6e876f7aba1c8f837d8aa713392)
@@ -46,6 +46,7 @@
 static BOOL ddOpModeDataFreshFlag;                                          ///< Flag to signal the handleDDOpMode() to process fresh dd op mode data.
 static BOOL ddDialysatePressureFreshFlag;                                   ///< Flag to signal
 
+static PRE_GEN_DIALYSATE_REQ_PAYLOAD_T preGenDialysateCmdSet;               ///< Set of pre-generate dialysate parameters to send to the DD
 static DIALYSATE_DELIVERY_REQ_PAYLOAD_T dialysateDeliveryCmdSet;            ///< Set of dialysate delivery parameters to send to the DD during treatment.
 
 // DD command response
@@ -100,6 +101,14 @@
     ddStarted                                 = FALSE;
     ddStartCommandSent                        = FALSE;
 
+    preGenDialysateCmdSet.start               = FALSE;
+    preGenDialysateCmdSet.dialRate            = 0.0F;
+    preGenDialysateCmdSet.dialTemp            = 0.0F;
+    preGenDialysateCmdSet.acidConvFactor      = 0.0F;
+    preGenDialysateCmdSet.bicarbConvFactor    = 0.0F;
+    preGenDialysateCmdSet.sodium              = 0;
+    preGenDialysateCmdSet.bicarbonate         = 0;
+
     dialysateDeliveryCmdSet.start             = FALSE;
     dialysateDeliveryCmdSet.dialRate          = 0.0F;
     dialysateDeliveryCmdSet.ufRate            = 0.0F;
@@ -285,6 +294,38 @@
 
 /*********************************************************************//**
  * @brief
+ * The cmdStartPreGenerateDialysate function sends a pre generate dialysate command
+ * to the DD with a given set of details.  DD will transition to pre generate
+ * dialysate mode if it hasn't already.
+ * @details \b Inputs: none
+ * @details \b Outputs: preGenDialysateCmdSet
+ * @details \b Message \b Sent: Start/continue pre-generate dialysate command.
+ * @param qd Target dialysate flow rate (Qd).
+ * @param dialTemp Target dialysate temperature in deg C.
+ * @param acidConvFactor Conversion factor for the acid used.
+ * @param bicarbConvFactor Conversion factor for the bicarbonate used.
+ * @param sodium Level of sodium used in mEq/L.
+ * @param bicarbonate Level of bicarbonate used in mEq/L.
+ * @return none
+ *************************************************************************/
+void cmdStartPreGenerateDialysate( F32 qd, F32 dialTemp, F32 acidConvFactor, F32 bicarbConvFactor, U32 sodium, U32 bicarbonate )
+{
+    preGenDialysateCmdSet.start            = TRUE;
+    preGenDialysateCmdSet.dialRate         = qd;
+    preGenDialysateCmdSet.dialTemp         = dialTemp;
+    preGenDialysateCmdSet.acidConvFactor   = acidConvFactor;
+    preGenDialysateCmdSet.bicarbConvFactor = bicarbConvFactor;
+    preGenDialysateCmdSet.sodium           = sodium;
+    preGenDialysateCmdSet.bicarbonate      = bicarbonate;
+
+#ifndef TEST_UI_ONLY
+    sendMessage( MSG_ID_DD_PRE_GEN_DIALYSATE_REQUEST_DATA, COMM_BUFFER_OUT_CAN_TD_2_DD, (U08*)(&preGenDialysateCmdSet), sizeof( PRE_GEN_DIALYSATE_REQ_PAYLOAD_T ) );
+#endif
+//    ddStartCommandSent = TRUE;
+}
+
+/*********************************************************************//**
+ * @brief
  * The cmdStartGenerateDialysate function sends a generate dialysate command
  * to the DD with a given set of details.  DD will transition to dialysate
  * delivery mode if it hasn't already.