Index: firmware/App/Services/PIControllers.c
===================================================================
diff -u -rea6ff77291eee02f351953b76c6720cf860c8be7 -r5217f70ca5c74bd586dc14540e6404b43feea004
--- firmware/App/Services/PIControllers.c	(.../PIControllers.c)	(revision ea6ff77291eee02f351953b76c6720cf860c8be7)
+++ firmware/App/Services/PIControllers.c	(.../PIControllers.c)	(revision 5217f70ca5c74bd586dc14540e6404b43feea004)
@@ -21,14 +21,14 @@
 
 // ********** private definitions **********
 
+#define MIN_KI                      NEARLY_ZERO
+
 typedef struct {
     // -- PI's parameters --
     F32 Kp;                         // Proportional Value
     F32 Ki;                         // Integral Value
     F32 uMax;                       // Maximum control signal
     F32 uMin;                       // Minimum control signal
-    F32 iMax;                       // Maximum error sum
-    F32 iMin;                       // Minimum error sum
     // -- PI's signals --
     F32 referenceSignal;            // reference signal
     F32 measuredSignal;             // measured signal
@@ -45,10 +45,10 @@
 // PI Controllers -- definition
 
 static PI_CONTROLLER_T piControllers[ NUM_OF_PI_CONTROLLERS_IDS ] =
-{   // Kp   Ki  uMax  uMin  iMax   iMin  ref meas  err  esw esum ctrl
-    { 0.0, 0.0,  1.0,  0.0, 10.0, -10.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },  // PI_CONTROLLER_ID_LOAD_CELL
-    { 0.0, 0.0,  1.0,  0.0, 10.0, -10.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },  // PI_CONTROLLER_ID_BLOOD_FLOW
-    { 0.0, 0.0,  1.0,  0.0, 10.0, -10.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }   // PI_CONTROLLER_ID_DIALYSATE_FLOW
+{   // Kp   Ki  uMax  uMin  ref meas  err  esw esum ctrl
+    { 0.0, 0.0,  1.0,  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },  // PI_CONTROLLER_ID_LOAD_CELL
+    { 0.0, 0.0, 0.90, 0.10, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },  // PI_CONTROLLER_ID_BLOOD_FLOW
+    { 0.0, 0.0, 0.90, 0.10, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }   // PI_CONTROLLER_ID_DIALYSATE_FLOW
 };
 
 /*************************************************************************
@@ -62,7 +62,7 @@
  * @return none
  *************************************************************************/
 void initializePIController( PI_CONTROLLER_ID_T controllerID, F32 initialControlSignal,
-                             F32 kP, F32 kI, F32 controlMin, F32 controlMax, F32 iMin, F32 iMax )
+                             F32 kP, F32 kI, F32 controlMin, F32 controlMax )
 {
     PI_CONTROLLER_T *controller;
 
@@ -71,11 +71,16 @@
         SET_CONTROLLER( controller, controllerID );
 
         controller->Kp = kP;
-        controller->Ki = kI;
+        if ( fabs( kI ) > MIN_KI )      // ensure kI is not zero
+        {
+            controller->Ki = kI;
+        }
+        else
+        {
+            controller->Ki = ( kI < 0.0 ? MIN_KI * -1.0 : MIN_KI );
+        }
         controller->uMin = controlMin;
         controller->uMax = controlMax;
-        controller->iMin = iMin;
-        controller->iMax = iMax;
         resetPIController( controllerID, initialControlSignal );
     }
 }
@@ -100,8 +105,8 @@
         controller->controlSignal = RANGE( initialControlSignal, controller->uMin, controller->uMax );
         controller->referenceSignal = 0.0;
         controller->errorSignal = 0.0;
-        controller->errorSumBeforeWindUp = 0.0;
-        controller->errorSum = 0.0;
+        controller->errorSum = controller->controlSignal / controller->Ki;
+        controller->errorSumBeforeWindUp = controller->errorSum;
         controller->measuredSignal = 0.0;
     }
 }
@@ -123,19 +128,27 @@
 
     if ( controllerID < NUM_OF_PI_CONTROLLERS_IDS )
     {
+        F32 controlSignalBeforeWindup;
+        F32 windupError;
+
         SET_CONTROLLER( controller, controllerID );
 
         controller->referenceSignal = referenceSignal;
         controller->measuredSignal = measuredSignal;
         // calculate error signal
         controller->errorSignal = fabs( referenceSignal ) - ( referenceSignal < 0.0 ? ( measuredSignal * -1.0 ) : measuredSignal );
-        controller->errorSumBeforeWindUp += controller->errorSignal;
+        controller->errorSum += controller->errorSignal;
         // anti-windup
-        controller->errorSum = RANGE( controller->errorSumBeforeWindUp, controller->iMin, controller->iMax );
+        controller->errorSumBeforeWindUp = controller->errorSum;
         // calculate control signal
-        controller->controlSignal += ( controller->Kp * controller->errorSignal ) + ( controller->Ki * controller->errorSum );
-        // limit control signal to valid range
-        controller->controlSignal = RANGE( controller->controlSignal, controller->uMin, controller->uMax );
+        controlSignalBeforeWindup = ( controller->Kp * controller->errorSignal ) + ( controller->Ki * controller->errorSum );
+        controller->controlSignal = RANGE( controlSignalBeforeWindup, controller->uMin, controller->uMax );
+        // handle anti-windup for i term
+        windupError = controller->controlSignal - controlSignalBeforeWindup;
+        if ( fabs( windupError ) > NEARLY_ZERO )
+        {
+            controller->errorSum -= ( windupError / controller->Ki );
+        }
         result = controller->controlSignal;
     }