Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r20fe5dc6869557f96c86fbd9d7f2f634ce23696a -r8d3dbd25627fb7e993409eb47b2575e0430afddd
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 20fe5dc6869557f96c86fbd9d7f2f634ce23696a)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 8d3dbd25627fb7e993409eb47b2575e0430afddd)
@@ -18,6 +18,7 @@
 #include "AirPump.h"
 #include "AirTrap.h"
 #include "AlarmMgmt.h"
+#include "BloodFlow.h"
 #include "FPGA.h"
 #include "ModeTreatmentParams.h"
 #include "OperationModes.h"
@@ -27,6 +28,7 @@
 #include "TaskGeneral.h"
 #include "TaskPriority.h"
 #include "Timers.h"
+#include "Valves.h"
 
 /**
  *  @addtogroup AirTrap
@@ -35,17 +37,16 @@
 
 // ********** private definitions **********
 
-
 #define AIR_TRAP_DATA_PUB_INTERVAL          ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )           ///< Interval (ms/task time) at which the air trap data is published on the CAN bus.
 #define AIR_TRAP_FILL_TIMEOUT_MS            ( 10 * MS_PER_SECOND )                              ///< Air trap fill timeout period (in ms).
 #define AIR_PUMP_ON_DELAY_TIME_MS           ( 10 * MS_PER_SECOND )                              ///< Delay between air pump On (in ms).
 #define AIR_PUMP_ON_STOP_TIME_MIN_MS        200                                                 ///< Stop air Pump time.
-#define AIR_PUMP_ON_ERROR_MAX_CNT           6                                                   ///< Maximum number of air pump on events within time window before alarm triggered. Do not exceed MAX_TIME_WINDOWED_COUNT.
-#define AIR_PUMP_ON_ERROR_TIME_WIN_MS       ( 60 * MS_PER_SECOND )                              ///< Time window for Air Pump on count error.
+#define AIR_TRAP_ACTIVITY_MAX_COUNT         5                                                   ///< Maximum number of air trap events (fills and air pump activations) within time window before alarm triggered.
+#define AIR_TRAP_ACTIVITY_TIME_WIN_MS       ( 5 * SEC_PER_MIN * MS_PER_SECOND )                 ///< Time window to monitor for too many air trap events.
 #define AIR_TRAP_LEVEL_DEBOUNCE_TIME_MS     ( 400 )                                             ///< Air trap level sensor debounce time
-/// Persistence period for illegal level sensors fault.
+// Persistence period for illegal level sensors fault.
 #define AIR_TRAP_ILLEGAL_LEVELS_TIMEOUT_MS  ( 2 * MS_PER_SECOND )                               ///< Air trap illegal values timeout (in ms)
-#define AIR_TRAP_UPPER_LEVEL_FLUID_TIMEOUT_MS ( 60 * MS_PER_SECOND )                            ///< Air trap upper level fluid timeout in milliseconds.
+#define AIR_TRAP_UPPER_LEVEL_FLUID_TIMEOUT_MS ( 30 * MS_PER_SECOND )                            ///< Air trap upper level fluid timeout in milliseconds.
 
 /// Volume (in mL) of venous portion of blood circuit line.  TODO - get actual volume from Systems.
 #define VENOUS_LINE_VOLUME_ML               ( 200.0F )
@@ -122,6 +123,7 @@
 
     initPersistentAlarm( ALARM_ID_HD_AIR_TRAP_ILLEGAL_LEVELS, AIR_TRAP_ILLEGAL_LEVELS_TIMEOUT_MS, AIR_TRAP_ILLEGAL_LEVELS_TIMEOUT_MS );
     initPersistentAlarm( ALARM_ID_HD_AIR_TRAP_UPPER_LEVEL_FLUID_TIME_OUT, 0, AIR_TRAP_UPPER_LEVEL_FLUID_TIMEOUT_MS );
+    initTimeWindowedCount( TIME_WINDOWED_COUNT_AIRTRAP_TOO_FREQ_ALARM, AIR_TRAP_ACTIVITY_MAX_COUNT, AIR_TRAP_ACTIVITY_TIME_WIN_MS );
 }
 
 /*********************************************************************//**
@@ -195,6 +197,26 @@
 
 /*********************************************************************//**
  * @brief
+ * The isAirTrapFillInProgress function determines whether the air trap is
+ * currently filling.
+ * @details Inputs: airTrapControllerState
+ * @details Outputs: none
+ * @return TRUE if air trap is currently filling, FALSE if not.
+ *************************************************************************/
+BOOL isAirTrapFillInProgress( void )
+{
+    BOOL result = FALSE;
+
+    if ( AIR_TRAP_VALVE_OPEN_STATE == airTrapControllerState )
+    {
+        result = TRUE;
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The execAirTrapMonitor function executes the air trap monitor.
  * @details Inputs: FPGA air trap levels GPIO pin levels, airTrapIllegalLevelSensorsCtr
  * @details Outputs: airTrapLevels[], airTrapIllegalLevelSensorsCtr
@@ -390,7 +412,7 @@
         }
     }
 
-    //Open valve once at start of treatment ( blood priming)
+    //Open valve once at start of treatment (blood priming)
     else if ( TRUE == airTrapValveOpenAtStartOfTreatement )
     {
         airTrapValveOpenAtStartOfTreatement = FALSE;
@@ -400,10 +422,12 @@
         }
 
         setValveAirTrap( STATE_OPEN );
+        signalBloodPumpHardStop();
+        setValvePosition( VBV, VALVE_POSITION_C_CLOSE );
         fillStartTime = getMSTimerCount();
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, STATE_OPEN, 0 );
-        result = AIR_TRAP_VALVE_OPEN_STATE;
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_STATE_CHANGE, (U32)AIR_TRAP_VALVE_CLOSED_STATE, (U32)result )
+        result = AIR_TRAP_VALVE_OPEN_STATE;
     }
 
     // Turn air pump off after defined time or air detected at upper level
@@ -422,9 +446,19 @@
         if ( ( AIR_PUMP_STATE_OFF == getAirPumpState() ) &&
              ( TRUE == didTimeout( airPumpOnDelayStartTime, AIR_PUMP_ON_DELAY_TIME_MS ) ) )
         {
-            setAirPumpState( AIR_PUMP_STATE_ON );
-            stopAirPumpStartTime = getMSTimerCount();
-            signalInitiatePressureStabilization( USE_SHORT_STABILIZATION_PERIOD );
+            // Check air trap activity (fills/air pump activations) too frequent
+            if ( TRUE == incTimeWindowedCount( TIME_WINDOWED_COUNT_AIRTRAP_TOO_FREQ_ALARM ) )
+            {
+                SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_AIR_TRAP_ACTIVITY_TOO_FREQUENT, TIME_WINDOWED_COUNT_AIRTRAP_TOO_FREQ_ALARM );
+                // reset alarm count after alarm so that time window does not interfere with alarm recovery
+                initTimeWindowedCount( TIME_WINDOWED_COUNT_AIRTRAP_TOO_FREQ_ALARM, AIR_TRAP_ACTIVITY_MAX_COUNT, AIR_TRAP_ACTIVITY_TIME_WIN_MS );
+            }
+            else
+            {
+                setAirPumpState( AIR_PUMP_STATE_ON );
+                stopAirPumpStartTime = getMSTimerCount();
+                signalInitiatePressureStabilization( USE_SHORT_STABILIZATION_PERIOD );
+            }
         }
     }
 
@@ -438,10 +472,12 @@
         }
 
         setValveAirTrap( STATE_OPEN );
+        signalBloodPumpHardStop();
+        setValvePosition( VBV, VALVE_POSITION_C_CLOSE );
         fillStartTime = getMSTimerCount();
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, STATE_OPEN, 0 );
-        result = AIR_TRAP_VALVE_OPEN_STATE;
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_STATE_CHANGE, (U32)AIR_TRAP_VALVE_CLOSED_STATE, (U32)result )
+        result = AIR_TRAP_VALVE_OPEN_STATE;
     }
 
     return result;
@@ -478,6 +514,7 @@
         result = AIR_TRAP_VALVE_CLOSED_STATE;
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_STATE_CHANGE, (U32)AIR_TRAP_VALVE_OPEN_STATE, (U32)result )
     }
+
     return result;
 }