Index: firmware/App/Services/PIControllers.c
===================================================================
diff -u -r9864b14f76782f1e68bf266dcd843451748715a0 -rd830f37cf6a42a16399c87985bd51dfd9312ced3
--- firmware/App/Services/PIControllers.c	(.../PIControllers.c)	(revision 9864b14f76782f1e68bf266dcd843451748715a0)
+++ firmware/App/Services/PIControllers.c	(.../PIControllers.c)	(revision d830f37cf6a42a16399c87985bd51dfd9312ced3)
@@ -1,17 +1,16 @@
-/**************************************************************************
+/**********************************************************************//**
  *
+ *  @file PIControllers.c
+ *
  *  Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
  *
  *  THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
  *  WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
  *
- *  @file PIControllers.c
- *
  *  @date 18-Dec-2019
  *  @author L. Baloa
  *
- *  @brief PIControllers service module.  Creates a digital PI to be used as
- *  control loops
+ *  @brief PIControllers source file.
  *
  **************************************************************************/
 
@@ -28,35 +27,34 @@
 
 typedef struct {
     // -- PI's parameters --
-    F32 Kp;                         // Proportional Value
-    F32 Ki;                         // Integral Value
-    F32 uMax;                       // Maximum control signal
-    F32 uMin;                       // Minimum control signal
+    F32 Kp;                         /// Proportional Value
+    F32 Ki;                         /// Integral Value
+    F32 uMax;                       /// Maximum control signal
+    F32 uMin;                       /// Minimum control signal
     // -- PI's signals --
-    F32 referenceSignal;            // reference signal
-    F32 measuredSignal;             // measured signal
-    F32 errorSignal;                // reference - measured signal
-    F32 errorSumBeforeWindUp;       // error signal before windup correction
-    F32 errorSum;                   // error integral after windup correction
-    F32 controlSignal;              // actual control signal
-} PI_CONTROLLER_T;
+    F32 referenceSignal;            /// reference signal
+    F32 measuredSignal;             /// measured signal
+    F32 errorSignal;                /// reference - measured signal
+    F32 errorSumBeforeWindUp;       /// error signal before windup correction
+    F32 errorSum;                   /// error integral after windup correction
+    F32 controlSignal;              /// actual control signal
+} PI_CONTROLLER_T;                  /// record for PI controller
 
-#define SET_CONTROLLER( c, id )                     ((c) = &piControllers[id])
+#define SET_CONTROLLER( c, id )     ((c) = &piControllers[id])          /// macro to set a local controller pointer to a given piController
 
 // ********** private data **********
 
-// PI Controllers -- definition
-
+/// PI Controllers -- initial configurations.
 static PI_CONTROLLER_T piControllers[ NUM_OF_PI_CONTROLLERS_IDS ] =
 {   // 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
 };
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief initializePIController
- * Initialize controller before operation. Make sure to call it before \n
+ * Initialize controller before operation. Make sure to call it before
  * first call to runController function.
  *
  * @param controllerID - ID filter number
@@ -86,11 +84,15 @@
         controller->uMax = controlMax;
         resetPIController( controllerID, initialControlSignal );
     }
+    else
+    {
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_PI_CTRL_INVALID_CONTROLLER, (U32)controllerID )
+    }
 }
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief resetPIController
- * Reset controller before new set point. Make sure to call it before first \n
+ * Reset controller before new set point. Make sure to call it before first
  * call to runController function.
  *
  * @param controllerID - ID filter number
@@ -112,9 +114,13 @@
         controller->errorSumBeforeWindUp = controller->errorSum;
         controller->measuredSignal = 0.0;
     }
+    else
+    {
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_PI_CTRL_INVALID_CONTROLLER, (U32)controllerID )
+    }
 }
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief runPIController
  * Call this function whenever a new measured signal sampled is acquired.
  *
@@ -171,11 +177,15 @@
 //    }
 //#endif
     }
+    else
+    {
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_PI_CTRL_INVALID_CONTROLLER, (U32)controllerID )
+    }
 
     return result;
 }
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief getPIControllerSignals
  * Returns the latest requested signal sample.
  *
@@ -228,10 +238,14 @@
                 break;
 
             default:
-                output = 0;
+                SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_PI_CTRL_INVALID_SIGNAL, (U32)signalID )
                 break;
         } // end of switch
     }
+    else
+    {   // invalid controller given
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_PI_CTRL_INVALID_CONTROLLER, (U32)controllerID )
+    }
 
     return output;
 }