Index: firmware/App/Controllers/DialOutFlow.c
===================================================================
diff -u -r5e85dc21e918ecdae841f8398bca20ff8823c52b -rafa9d4924d55ac4fc98270a012e92dd1f6ee65d0
--- firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 5e85dc21e918ecdae841f8398bca20ff8823c52b)
+++ firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision afa9d4924d55ac4fc98270a012e92dd1f6ee65d0)
@@ -44,16 +44,18 @@
 
 #define MAX_DIAL_OUT_FLOW_RATE                  650             ///< Maximum dialysate outlet pump flow rate in mL/min.
 #define MIN_DIAL_OUT_FLOW_RATE                  100             ///< Minimum dialysate outlet pump flow rate in mL/min.
-#define DPO_FLOW_ADJ_DUE_TO_HIGHER_INLET_PRES   1.200           ///< Adjustment factor to account for higher pump inlet pressure (than DPi pump inlet).
 
 #define MAX_DIAL_OUT_PUMP_PWM_STEP_UP_CHANGE    0.0133          ///< Maximum duty cycle change when ramping up ~ 200 mL/min/s.
 #define MAX_DIAL_OUT_PUMP_PWM_STEP_DN_CHANGE    0.02            ///< Maximum duty cycle change when ramping down ~ 300 mL/min/s.
 #define MAX_DIAL_OUT_PUMP_PWM_DUTY_CYCLE        0.89            ///< Controller will error if PWM duty cycle > 90%, so set max to 89%.
 #define MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE        0.10            ///< Controller will error if PWM duty cycle < 10%, so set min to 10%.
+#define MAX_DIAL_OUT_PUMP_PWM_OFFSET_CONTROL    0.4             ///< Maximum PWM offset (added to DPi PWM duty cycle).
+#define MIN_DIAL_OUT_PUMP_PWM_OFFSET_CONTROL   -0.4             ///< Minimum PWM offset (added to DPi PWM duty cycle).
 
+#define DOP_CONTROL_INTERVAL_SEC                5               ///< Dialysate outlet pump control interval (in seconds).
 /// Interval (ms/task time) at which the dialysate outlet pump is controlled.
-static const U32 DOP_CONTROL_INTERVAL         = ( 2000 / TASK_GENERAL_INTERVAL );
-#define DOP_P_COEFFICIENT                       0.0050          ///< P term for dialysate outlet pump control.
+static const U32 DOP_CONTROL_INTERVAL         = ( DOP_CONTROL_INTERVAL_SEC * MS_PER_SECOND / TASK_GENERAL_INTERVAL );
+#define DOP_P_COEFFICIENT                       0.0010          ///< P term for dialysate outlet pump control.
 #define DOP_I_COEFFICIENT                       0.0001          ///< I term for dialysate outlet pump control.
 
 #define DOP_HOME_RATE                           100             ///< Target pump speed (in estimate mL/min) for homing.
@@ -83,11 +85,12 @@
 
 #ifndef V2_0_SYSTEM
     #define DOP_SPEED_ADC_TO_RPM_FACTOR         1.751752        ///< Conversion factor from ADC counts to RPM for dialysate outlet pump motor.
-    #define DOP_MOTOR_RPM_TO_PWM_DC_FACTOR      0.00025         ///< ~40 BP motor RPM = 1% PWM duty cycle
+    #define DOP_MOTOR_RPM_TO_PWM_DC_FACTOR      0.000193        ///< ~52 BP motor RPM = 1% PWM duty cycle
 #else
     #define DOP_SPEED_ADC_TO_RPM_FACTOR         1.280938        ///< Conversion factor from ADC counts to RPM for blood pump motor
     #define DOP_MOTOR_RPM_TO_PWM_DC_FACTOR      0.0003125       ///< ~32 BP motor RPM = 1% PWM duty cycle
 #endif
+#define UF_PWM_DC_PCT_PER_ML_PER_MIN            0.004           ///< Estimated DPo PWM duty cycle amount per each mL/min of ultrafiltration desired.
 #define DOP_CURRENT_ADC_TO_MA_FACTOR            3.002           ///< Conversion factor from ADC counts to mA for dialysate outlet pump motor.
 #define DOP_ADC_FULL_SCALE_V                    3.0             ///< DPo analog signals are 0-3V (while int. ADC ref V may be different).
 #define DOP_ADC_ZERO                            1998            ///< Mid-point (zero) for ADC readings.
@@ -214,9 +217,8 @@
     }
 
     // Initialize dialysate outlet flow PI controller
-    initializePIController( PI_CONTROLLER_ID_ULTRAFILTRATION, MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE,
-                            DOP_P_COEFFICIENT, DOP_I_COEFFICIENT,
-                            MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE, MAX_DIAL_OUT_PUMP_PWM_DUTY_CYCLE );
+    initializePIController( PI_CONTROLLER_ID_ULTRAFILTRATION, 0.0, DOP_P_COEFFICIENT, DOP_I_COEFFICIENT,
+                            MIN_DIAL_OUT_PUMP_PWM_OFFSET_CONTROL, MAX_DIAL_OUT_PUMP_PWM_OFFSET_CONTROL );
 }
 
 /*********************************************************************//**
@@ -237,15 +239,13 @@
     // Direction change while pump is running is not allowed
     if ( ( FALSE == isDialOutPumpOn ) || ( 0 == flowRate ) || ( dir == dialOutPumpDirectionSet ) )
     {
+#ifndef NO_PUMP_FLOW_LIMITS
         // Verify flow rate
         if ( flowRate <= MAX_DIAL_OUT_FLOW_RATE )
+#endif
         {
             F32 adjFlow = (F32)flowRate;
 
-            if ( PUMP_CONTROL_MODE_CLOSED_LOOP == mode )
-            {
-                adjFlow *= DPO_FLOW_ADJ_DUE_TO_HIGHER_INLET_PRES;
-            }
             lastGivenRate = flowRate;
             dialOutPumpDirection = dir;
             dialOutPumpControlMode = mode;
@@ -283,10 +283,12 @@
             }
             result = TRUE;
         }
+#ifndef NO_PUMP_FLOW_LIMITS
         else  // Requested flow rate too high
         {
             SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_DIAL_OUT_FLOW_SET_TOO_HIGH, flowRate )
         }
+#endif
     }
 
     return result;
@@ -511,14 +513,18 @@
     // Have we reached end of ramp up?
     else if ( dialOutPumpPWMDutyCyclePctSet >= dialOutPumpPWMDutyCyclePct )
     {
-        resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, dialOutPumpPWMDutyCyclePctSet );
-        dialOutPumpControlModeSet = dialOutPumpControlMode;
-        // If open loop mode, set PWM to requested duty cycle where it will stay during control state
-        if ( dialOutPumpControlModeSet == PUMP_CONTROL_MODE_OPEN_LOOP )
+        dialOutPumpPWMDutyCyclePctSet = dialOutPumpPWMDutyCyclePct;
+        if ( dialOutPumpControlMode == PUMP_CONTROL_MODE_OPEN_LOOP )
         {
-            dialOutPumpPWMDutyCyclePctSet = dialOutPumpPWMDutyCyclePct;
-            setDialOutPumpControlSignalPWM( dialOutPumpPWMDutyCyclePct );
+            resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, dialOutPumpPWMDutyCyclePctSet );
         }
+        else
+        {   // Closed loop UF control is only controlling offset from DPi PWM
+            resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, (F32)( (S32)lastGivenRate - getTargetDialInFlowRate() ) * UF_PWM_DC_PCT_PER_ML_PER_MIN );
+        }
+        dialOutPumpControlModeSet = dialOutPumpControlMode;
+        setDialOutPumpControlSignalPWM( dialOutPumpPWMDutyCyclePctSet );
+        dopControlTimerCounter = 0;
         result = DIAL_OUT_PUMP_CONTROL_TO_TARGET_STATE;
     }
     // Continue ramp up
@@ -552,14 +558,18 @@
     // Have we reached end of ramp down?
     else if ( dialOutPumpPWMDutyCyclePctSet <= dialOutPumpPWMDutyCyclePct )
     {
-        resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, dialOutPumpPWMDutyCyclePctSet );
-        dialOutPumpControlModeSet = dialOutPumpControlMode;
-        // If open loop mode, set PWM to requested duty cycle where it will stay during control state
-        if ( dialOutPumpControlModeSet == PUMP_CONTROL_MODE_OPEN_LOOP )
+        dialOutPumpPWMDutyCyclePctSet = dialOutPumpPWMDutyCyclePct;
+        if ( ( dialOutPumpControlModeSet == PUMP_CONTROL_MODE_OPEN_LOOP ) || ( 0 == lastGivenRate ) )
         {
-            dialOutPumpPWMDutyCyclePctSet = dialOutPumpPWMDutyCyclePct;
-            setDialOutPumpControlSignalPWM( dialOutPumpPWMDutyCyclePct );
+            resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, dialOutPumpPWMDutyCyclePctSet );
         }
+        else
+        {   // Closed loop UF control is only controlling offset from DPi PWM
+            resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, (F32)( (S32)lastGivenRate - getTargetDialInFlowRate() ) * UF_PWM_DC_PCT_PER_ML_PER_MIN );
+        }
+        dialOutPumpControlModeSet = dialOutPumpControlMode;
+        setDialOutPumpControlSignalPWM( dialOutPumpPWMDutyCyclePct );
+        dopControlTimerCounter = 0;
         result = DIAL_OUT_PUMP_CONTROL_TO_TARGET_STATE;
     }
     // Continue ramp down
@@ -591,22 +601,17 @@
         {
             F32 refVol = getTotalTargetDialOutUFVolumeInMl();
             F32 totVol = getTotalMeasuredUFVolumeInMl();
-            F32 newPWMDutyCyclePct;
-            F32 deltaPWMDutyCyclePct;
+            F32 offsetPWMDutyCyclePct;
 
-            // Get new PWM from PI controller
-            newPWMDutyCyclePct = runPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, refVol, totVol );
-            // Limit PWM change to max
-            deltaPWMDutyCyclePct = newPWMDutyCyclePct - dialOutPumpPWMDutyCyclePctSet;
-            if ( fabs( deltaPWMDutyCyclePct ) > MAX_DIAL_OUT_PUMP_PWM_STEP_UP_CHANGE )
-            {
-                newPWMDutyCyclePct = ( deltaPWMDutyCyclePct < 0.0 ? \
-                                       dialOutPumpPWMDutyCyclePctSet - MAX_DIAL_OUT_PUMP_PWM_STEP_UP_CHANGE : \
-                                       dialOutPumpPWMDutyCyclePctSet + MAX_DIAL_OUT_PUMP_PWM_STEP_UP_CHANGE );
-            }
-            // Set new PWM
-            dialOutPumpPWMDutyCyclePctSet = newPWMDutyCyclePct;
-            setDialOutPumpControlSignalPWM( newPWMDutyCyclePct );
+            // Get new PWM offset from PI controller
+            offsetPWMDutyCyclePct = runPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, refVol, totVol );
+            // Add PWM offset to DPi PWM mirror for our new DPo PWM
+            dialOutPumpPWMDutyCyclePctSet = getDialInPumpPWMDutyCyclePct() + offsetPWMDutyCyclePct;
+            // Limit PWM range
+            dialOutPumpPWMDutyCyclePctSet = MIN( dialOutPumpPWMDutyCyclePctSet, MAX_DIAL_OUT_PUMP_PWM_DUTY_CYCLE );
+            dialOutPumpPWMDutyCyclePctSet = MAX( dialOutPumpPWMDutyCyclePctSet, MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE );
+            // Apply new PWM to DPo pump
+            setDialOutPumpControlSignalPWM( dialOutPumpPWMDutyCyclePctSet );
         }
         dopControlTimerCounter = 0;
     }