Index: firmware/App/Controllers/SyringePump.c
===================================================================
diff -u -r5b3be58e0b2dc2ffce534363f85023d03ca561ba -r735226fefeab1dc5219d6cebee749e0c27b2ce21
--- firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision 5b3be58e0b2dc2ffce534363f85023d03ca561ba)
+++ firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision 735226fefeab1dc5219d6cebee749e0c27b2ce21)
@@ -161,12 +161,12 @@
 static U32 syringePumpSetToggleTime;                                            ///< Set rate for syringe pump (in uSec/toggle).
 static U32 syringePumpRampUpToggleTime;                                         ///< Current ramp rate for syringe pump (in uSec/toggle).
 static F32 syringePumpSafetyVolumeDelivered;                                    ///< Calculated volume (in mL) (from set rate over time).
+static S32 syringePumpVolumeStartPosition;                                      ///< Start position for the current volume calculation.
 static S32 syringePumpHomePositionOffset;                                       ///< FPGA reported position when at home postion.
 static S32 syringePumpPosition1SecAgo;                                          ///< Position recorded at last 1 Hz speed check.
 
 static BOOL syringePumpRetractRequested;                                        ///< Flag indicates a retract operation is requested.
 static BOOL syringePumpPrimeRequested;                                          ///< Flag indicates plunger seek and Heparin prime operations are requested.
-static BOOL syringePumpSeekToPrimeRequested;                                    ///< Flag indicates plunger seek finished, pump stopped, now requesting prime operation.
 static BOOL syringePumpBolusRequested;                                          ///< Flag indicates start or resume of a Heparin bolus operation is requested.
 static BOOL syringePumpContinuousRequested;                                     ///< Flag indicates start or resume of a Heparin continuous delivery operation is requested.
 static BOOL syringePumpDACVrefSetRequested;                                     ///< Flag indicates request to set DAC Vref for force sensor.
@@ -223,6 +223,7 @@
     syringePumpSetRate = 0.0;
     syringePumpSetToggleTime = 0;
     syringePumpSafetyVolumeDelivered = 0.0;
+    syringePumpVolumeStartPosition = 0;
     syringePumpHomePositionOffset = 0;
     syringePumpPosition1SecAgo = 0;
 
@@ -248,7 +249,6 @@
 {
     syringePumpRetractRequested = FALSE;
     syringePumpPrimeRequested = FALSE;
-    syringePumpSeekToPrimeRequested = FALSE;
     syringePumpBolusRequested = FALSE;
     syringePumpContinuousRequested = FALSE;
     syringePumpDACVrefSetRequested = FALSE;
@@ -606,7 +606,7 @@
     // Apply home offset to encoder position
     syringePumpPosition.data = encPosition - syringePumpHomePositionOffset;
     // Calculate volume delivered from position
-    syringePumpVolumeDelivered.data = (F32)(syringePumpPosition.data) / SYRINGE_ENCODER_COUNTS_PER_ML;
+    syringePumpVolumeDelivered.data = (F32)(syringePumpPosition.data - syringePumpVolumeStartPosition) / SYRINGE_ENCODER_COUNTS_PER_ML;
     calcSafetyVolumeDelivered();
     // Calculate measured rate (mL/hr)
     calcMeasRate();
@@ -725,11 +725,6 @@
     {
         result = SYRINGE_PUMP_SEEK_STATE;
     }
-    else if ( TRUE == syringePumpSeekToPrimeRequested )
-    {
-        result = SYRINGE_PUMP_PRIME_STATE;
-        syringePumpSetRate = SYRINGE_PUMP_PRIME_RATE;
-    }
     else if ( TRUE == syringePumpBolusRequested )
     {
         result = SYRINGE_PUMP_HEP_BOLUS_STATE;
@@ -793,6 +788,7 @@
         stopSyringePump();
         syringePumpHomePositionOffset = getFPGASyringePumpEncoderPosition();
         syringePumpPosition.data = 0;
+        syringePumpVolumeStartPosition = 0;
         syringePumpVolumeDelivered.data = 0.0;
         result = SYRINGE_PUMP_OFF_STATE;
     }
@@ -824,11 +820,15 @@
     rampSyringePump();
 
     // Is plunger contact detected?
-    if ( ( syringePumpRampTimerCtr > 500 ) ) //|| ( getSyringePumpForceV() >= SYRINGE_FORCE_PLUNGER_THRESHOLD_V ) )
+    if ( ( syringePumpRampTimerCtr > 800 ) || ( getSyringePumpForceV() >= SYRINGE_FORCE_PLUNGER_THRESHOLD_V ) )
     {
-        stopPump = TRUE;
         syringePumpVolumeDelivered.data = 0.0;
-//        syringePumpSeekToPrimeRequested = TRUE;
+        syringePumpVolumeStartPosition = syringePumpPosition.data;
+        syringePumpSetRate = SYRINGE_PUMP_PRIME_RATE;
+        // Calculate target FPGA rate from set rate in mL/hr converted to microstep toggle interval in uSec
+        calcStepperToggleTimeForTargetRate( syringePumpSetRate );
+        setFPGASyringePumpStepToggleTime( syringePumpRampUpToggleTime );
+        result = SYRINGE_PUMP_PRIME_STATE;
     }
 
     // Has syringe been removed?
@@ -868,6 +868,7 @@
     {
         stopPump = TRUE;
         syringePumpVolumeDelivered.data = 0.0;
+        syringePumpVolumeStartPosition = syringePumpPosition.data;
     }
 
     // Has syringe been removed?