diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
index 90ac8dbc..b2971516 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
@@ -93,7 +93,7 @@ public class MpMasterService extends Service {
 
     private static int mStateService = STATE_SERVICE.NOT_CONNECTED;
 
-    private int mMpHeartbeatDuration = 10;
+    private int mMpHeartbeatDuration = 10;  // Unit: minute
 
     private boolean mMntnMode = false;
     private boolean mQuickHbMode = false;
@@ -486,30 +486,37 @@ public class MpMasterService extends Service {
         public void onReceive(Context context, Intent intent) {
             String action = intent.getAction();
             if (TextUtils.equals(ACTION_HEARTBEAT, action)) {
-                mService.logger.info("Heartbeat Timer Fired ACTION=" + action);
+                boolean keepAlive = intent.getBooleanExtra("keepAlive", false);
+                if (keepAlive) {
+                    mService.logger.info("KeepAlive Heartbeat Timer Fired ACTION=" + action);
+                } else {
+                    mService.logger.info("Heartbeat Timer Fired ACTION=" + action);
+                }
 
                 mService.mPreviousHB = null;
                 mService.registerHeartbeatTimer();
 
-                mService.startMaster(false);
+                if (!keepAlive) {
+                    mService.startMaster(false);
+                }
                 mService.startMpApp();
 
             } else if (TextUtils.equals(MicroPhotoContext.ACTION_HEARTBEAT_MP, action)) {
 
                 mService.mPreviousMpHbTime = System.currentTimeMillis();
-                mService.mMpHeartbeatDuration = intent.getIntExtra("HeartbeatDuration", 10);
+                if (intent.hasExtra("HeartbeatDuration")) {
+                    mService.mMpHeartbeatDuration = intent.getIntExtra("HeartbeatDuration", 10);
+                }
 
-                if (!mService.mSeparateNetwork && (!mService.mMntnMode)) {
-                    mService.logger.info("Heartbeat Timer Fired By MpAPP ACTION=" + action);
+                mService.logger.info("Heartbeat Timer Fired By MpAPP ACTION=" + action);
 
-                    long ts = System.currentTimeMillis();
-                    if (mService.mPreviousHeartbeatTime - ts < mService.mHeartbeatDuration * 1000) {
-                        mService.registerHeartbeatTimer(mService.mPreviousHeartbeatTime + mService.mHeartbeatDuration * 1000);
-                    }
+                mService.registerHeartbeatTimer();
 
+                if (!mService.mSeparateNetwork && (!mService.mMntnMode)) {
                     mService.startMaster(true);
-                    mService.startMpApp();
                 }
+                mService.startMpApp();
+
 
             } else if (TextUtils.equals(ACTION_UPDATE_CONFIGS, action)) {
                 int restart = intent.getIntExtra("restart", 0);
@@ -576,11 +583,13 @@ public class MpMasterService extends Service {
     private void registerHeartbeatTimer() {
 
         long timeout = mHeartbeatDuration;
+        boolean keepAlive = false;
+        long currentTimeMs = System.currentTimeMillis();
         if (mMntnMode) {
             if (mQuickHbMode) {
                 timeout = mQuickHeartbeatDuration;
             }
-            registerHeartbeatTimer(System.currentTimeMillis() + timeout * 1000);
+            registerHeartbeatTimer(currentTimeMs + timeout * 1000, keepAlive);
         } else {
             long closestTime = -1;
             if (mUsingAbsHbTime) {
@@ -616,18 +625,30 @@ public class MpMasterService extends Service {
                     }
                 }
 
-                registerHeartbeatTimer(zeroPoint + closestTime * 1000);
+                if (zeroPoint + closestTime > currentTimeMs + mMpHeartbeatDuration * 60000) {
+                    keepAlive = true;
+                    registerHeartbeatTimer(currentTimeMs + timeout * 1000, keepAlive);
+                } else {
+                    registerHeartbeatTimer(zeroPoint + closestTime * 1000, keepAlive);
+                }
             } else {
-                registerHeartbeatTimer(System.currentTimeMillis() + timeout * 1000);
+                if (mPreviousHeartbeatTime - currentTimeMs < mHeartbeatDuration * 1000) {
+                    registerHeartbeatTimer(mPreviousHeartbeatTime + mHeartbeatDuration * 1000, keepAlive);
+                } else {
+                    registerHeartbeatTimer(currentTimeMs + timeout * 1000, keepAlive);
+                }
             }
         }
     }
 
-    private void registerHeartbeatTimer(long triggerTime) {
+    private void registerHeartbeatTimer(long triggerTime, boolean keepAlive) {
 
         AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
+        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+
         if (mPreviousHB != null) {
             try {
+                logger.info(String.format("Cancel Previos HB: " + format.format(new Date(mPreviousHeartbeatTime))));
                 alarmManager.cancel(mPreviousHB);
                 mPreviousHB = null;
             } catch (Exception ex) {
@@ -636,11 +657,18 @@ public class MpMasterService extends Service {
         }
         Intent alarmIntent = new Intent();
         alarmIntent.setAction(ACTION_HEARTBEAT);
+        if (keepAlive) {
+            alarmIntent.putExtra("keepAlive", keepAlive);
+        }
         PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
 
         Date dt = new Date(triggerTime);
-        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-        logger.info(String.format("Register HB:" + format.format(dt)) + " MntnMode" + (mMntnMode ? "1" : "0") + " QuickHb=" + (mQuickHbMode ? "1" : "0"));
+
+        if (keepAlive) {
+            logger.info(String.format("Register KeepAlive HB: " + format.format(dt)) + " MntnMode=" + (mMntnMode ? "1" : "0") + " QuickHb=" + (mQuickHbMode ? "1" : "0"));
+        } else {
+            logger.info(String.format("Register HB: " + format.format(dt)) + " MntnMode=" + (mMntnMode ? "1" : "0") + " QuickHb=" + (mQuickHbMode ? "1" : "0"));
+        }
         mPreviousHB = pendingIntent;
         mPreviousHeartbeatTime = triggerTime;
         alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, triggerTime, pendingIntent);