Index: firmware/App/Controllers/DialOutFlow.c
===================================================================
diff -u -r8ce8a04d4c7871337a6fa53dc8844bcc3c2c955b -r3d8d8451d10aaf2ea9fc9d83857699ef1ae1a0be
--- firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 8ce8a04d4c7871337a6fa53dc8844bcc3c2c955b)
+++ firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 3d8d8451d10aaf2ea9fc9d83857699ef1ae1a0be)
@@ -55,20 +55,21 @@
 #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_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 P_UF                        0.001
-#define P_CORR                      0.1666
+#define P_VOL                                   0.001           ///< P term for volume error feedback into dialysate outlet pump control.
+#define P_UF                                    0.001           ///< P term for UF rate error feedback into dialysate outlet pump control.
+#define P_CORR                                  0.1666          ///< P term for volume error feedback into dialysate outlet pump flow estimate correction offset.
 
-#define RPM_2_ML_MIN_CONVERSION     0.215964
-#define SIZE_OF_ROLLING_AVG         100
+#define RPM_2_ML_MIN_CONVERSION                 0.215964        ///< Conversion factor for estimating flow rate from pump motor RPM.
+#define SIZE_OF_ROLLING_AVG                     100             ///< Number of samples in DPo flow estimation moving average.
 
 #define DOP_HOME_RATE                           100             ///< Target pump speed (in estimate mL/min) for homing.
 #define DOP_HOME_TIMEOUT_MS                     10000           ///< Maximum time allowed for homing to complete (in ms).
+
 /// Interval (ms/task time) at which the blood pump speed is calculated (every 40 ms).
 #define DOP_SPEED_CALC_INTERVAL                 ( 40 / TASK_PRIORITY_INTERVAL )
 /// Number of hall sensor counts kept in buffer to hold last 1 second of count data.
 #define DOP_SPEED_CALC_BUFFER__LEN              ( 1000 / DOP_SPEED_CALC_INTERVAL / TASK_PRIORITY_INTERVAL )
+
 #define DOP_HALL_EDGE_COUNTS_PER_REV            48              ///< Number of hall sensor edge counts per motor revolution.
 
 #define DOP_MAX_MOTOR_SPEED_WHILE_OFF_RPM       100.0           ///< Maximum motor speed (RPM) while motor is commanded off.
@@ -157,17 +158,17 @@
 static OVERRIDE_F32_T dialOutPumpSpeedRPM = { 0.0, 0.0, 0.0, 0 };                           ///< Measured dialysate outlet pump motor speed.
 
 static F32 offsetPWMDutyCyclePct = 0.0;                                                     ///< PWM duty cycle percentage offset to add to inlet pump duty cycle for UF control.
-static F32 dopMeasuredRate = 0.0;
-static F32 ufMeasuredRate = 0.0;
-static F32 dopRateCorrectionOffset = 0.0;
+static F32 dopMeasuredRate = 0.0;                                                           ///< Estimated flow rate for dialysate outlet pump.
+static F32 ufMeasuredRate = 0.0;                                                            ///< Calculated UF flow rate from measured dialysate flow rate subtracted from estimated dialysate outlet flow rate.
+static F32 dopRateCorrectionOffset = 0.0;                                                   ///< Correction offset for estimated flow rate for dialysate outlet pump.
 
-static U32 flowFilterTimerCount = 0;
+static U32 flowFilterTimerCtr = 0;                                                          ///< Timer counter for determining when to add a new sample to the moving average.
 static F64 flowReadings[ SIZE_OF_ROLLING_AVG ];                                             ///< Holds flow samples for a rolling average.
 static U32 flowReadingsIdx = 0;                                                             ///< Index for next sample in rolling average array.
 static F64 flowReadingsTotal = 0.0;                                                         ///< Rolling total - used to calc average.
 static U32 flowReadingsCount = 0;                                                           ///< Number of samples in flow rolling average buffer.
 
-static BOOL dopControlSignal = FALSE;
+static BOOL dopControlSignal = FALSE;                                                       ///< Control signal for syncing UF control to follow control interval of dialysate inlet pump.
 
 static U32 dopCurrErrorDurationCtr = 0;                                                     ///< Timer counter for motor current error persistence.
 
@@ -234,10 +235,6 @@
     ufMeasuredRate = 0.0;
     dopRateCorrectionOffset = 40.0;  // TODO - set to 0.0 when we have a better dop flow estimate.
     resetDialOutFlowMovingAverage();
-
-    // Initialize dialysate outlet flow PI controller
-    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 );
 }
 
 /*********************************************************************//**
@@ -346,7 +343,6 @@
     dialOutPumpState = DIAL_OUT_PUMP_OFF_STATE;
     dialOutPumpPWMDutyCyclePct = 0.0;
     resetDialOutFlowMovingAverage();
-    resetPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE );
 }
 
 /*********************************************************************//**
@@ -480,9 +476,9 @@
     updateDialOutPumpSpeedAndDirectionFromHallSensors();
 
     // Filter estimated dialysate out flow rate and calculate UF rate
-    if ( ++flowFilterTimerCount >= DIAL_OUT_FILTER_INTERVAL )
+    if ( ++flowFilterTimerCtr >= DIAL_OUT_FILTER_INTERVAL )
     {
-        flowFilterTimerCount = 0;
+        flowFilterTimerCtr = 0;
         // Calculate DPo flow in mL/min
         filterDialOutFlowReadings( getMeasuredDialOutPumpMCSpeed() * RPM_2_ML_MIN_CONVERSION );
         // Calculate UF flow in mL/min
@@ -673,7 +669,7 @@
 
             dopRateCorrectionOffset += ( ( totVol - refVol ) * P_CORR );
 
-            offsetPWMDutyCyclePct += volErr * DOP_P_COEFFICIENT;
+            offsetPWMDutyCyclePct += volErr * P_VOL;
             offsetPWMDutyCyclePct += ( ufrErr * P_UF );
 
             // Add PWM offset to DPi PWM mirror for our new DPo PWM