diff --git a/tecs/tecs.c b/tecs/tecs.c
index 94fe5af..440c725 100644
--- a/tecs/tecs.c
+++ b/tecs/tecs.c
@@ -176,7 +176,8 @@ static int
   nScan=0, /* number of scanned channels */
   alarmListSize=0,
   keepT=0, /* keep control over power-up */
-  swRangeOn=0, /* switch heater range on when controller switched it off */
+  swRangeOn=60, /* when not happen several times with less than 60 sec. delay,
+                   switch heater range on when controller switched it off */
   initMaxPower=0, /* set MaxPower for the first time */
   lockAlarm,
   cntError;
@@ -221,7 +222,7 @@ static float gradata[COC_RES_LEN/4-100];
 static char grapar[128];
 static int* grasize;
 
-static char ttp[64]; /* temperature, target and power */
+static char ttp[80]; /* temperature, target and power */
 
 typedef struct {
   char cmd[COC_CMD_LEN];
@@ -622,7 +623,7 @@ again:
     tLimit=0;
     tMaxLimit=0;
     keepT=0;
-    swRangeOn=0;
+    swRangeOn=60;
     loop=1;
     initMaxPower=1;
     resist=10;
@@ -1203,6 +1204,10 @@ float Power2Percent(float power) {
 }
 
 int ReadHeater(int full) {
+  static time_t lastOff=0;
+  static int cntOff=3;
+  time_t now;
+
   if (loop==1) {
     if (full) {
       if (relay) {
@@ -1212,8 +1217,22 @@ int ReadHeater(int full) {
         ERR_P(LscCmd(ser, "HTR?>htr;HTRST?>htrst;RELAYST?1>relay;RANGE?>ibuf"));
         if (jRange!=0 && ibuf==0) {
           if (swRangeOn) {
-            logfileOut(LOG_MAIN, "controller switched heater off - switch on again\n");
-            ERR_P(LscCmd(ser, "RANGE:[jRange]"));
+            time(&now);
+            if (lastOff > 0) {
+              if (now > lastOff + swRangeOn * 2) {
+                if (cntOff < 3) cntOff++;
+              } else if (now < lastOff + swRangeOn) {
+                cntOff--;
+              }
+            }
+            lastOff = now;
+            if (cntOff > 0) {
+              logfileOut(LOG_MAIN, "controller switched heater off - switch on again (%d more tries)\n", cntOff-1);
+              ERR_P(LscCmd(ser, "RANGE:[jRange]"));
+            } else {
+              logfileOut(LOG_MAIN, "controller switched heater off definitely (happened to often)\n");
+              jRange=0;
+            }
           } else {
             logfileOut(LOG_MAIN, "controller switched heater off\n");
             jRange=0;
@@ -1260,7 +1279,7 @@ int SetTemp(int switchOn) {
   tLim = (tLimit+tMaxLimit)*0.5;
   if (set+tShift <= 0) { /* set + tShift must not be negative */
     tShift = -0.999 * set;
-  } else if (set + tShift > tLim) {  /* prevent overshoot */
+  } else if (set + tShift > tLim) {  /* prevent limit overshoot */
     tShift = tLim - set;
   }
   setH=FakeScale(ctlSens, set+tShift);
@@ -2130,7 +2149,6 @@ void maxSlope(Slope *s, float value) {
 
 static Slope slopeS, slopeU, slopeL;
 
-
 int PeriodicTask(void) {
   char buf[256], lbuf[16];
   char *next, *alms;
@@ -2290,7 +2308,7 @@ int PeriodicTask(void) {
 
   ERR_I(ReadTemp());
 
-  snprintf(ttp, sizeof(ttp), "%.6g %.6g %.6g", tm, tr, power);
+  snprintf(ttp, sizeof(ttp), "%.6g %.6g %.6g %.6g %.6g", tm, tr, power, tx, set);
 
   if (htrst!=htrst0) {
     LogMinMax(0);
@@ -2397,9 +2415,10 @@ int PeriodicTask(void) {
       if (oldSet == 0) oldSet = samp.temp;
       if (oldSet != set || fabsf(d) > 50*ml) {
         if (oldSet != set) {
-	  if (set < oldSet) {
-	    tShift *= set/oldSet;
-	  }
+          float f = fabsf((oldSet - set)/ (oldSet + set));
+          oldShift *= exp(-f*f*25);
+          tShift = oldShift;
+	  statCrop(&mStat, sStat.lower+tShift, sStat.upper+tShift);
           state = 1;
 	} else {
 	  state = 0;
@@ -2424,16 +2443,18 @@ int PeriodicTask(void) {
 	}
       } else {
         if (state != 2) {
-          tShift = oldShift;
+          /* tShift = oldShift; */
           state = 2;
 	  statCrop(&mStat, sStat.lower+tShift, sStat.upper+tShift);
+        } else {
+          if (shiftLow > tShift) {
+            tShift = shiftLow;
+            oldShift = tShift;
+          } else if (shiftUp < tShift) {
+            tShift = shiftUp;
+            oldShift = tShift;
+          }
         }
-	if (shiftLow > tShift) {
-          tShift = shiftLow;
-        } else if (shiftUp < tShift) {
-          tShift = shiftUp;
-        }
-        oldShift = tShift;
       }
       if (tShift > ml * maxShift) {
         tShift = ml * maxShift;