diff --git a/fhem/FHEM/10_KNX.pm b/fhem/FHEM/10_KNX.pm
index 3f1e0f5ee..b4456150e 100644
--- a/fhem/FHEM/10_KNX.pm
+++ b/fhem/FHEM/10_KNX.pm
@@ -23,6 +23,8 @@
 # ABU 20180605 Added example for autogenerated devices
 # ABU 20180605 Added workaround for STATE
 # ABU 20180606 Fixed dpt18, fixed offset-addition in decode (was "-" instead of "+"), fixed issue with slider
+# ABU 20180607 seperated limit and scale from encode/decode in order to avoid warnings and clean up
+# ABU 20180613 fixed scaling algo
 
 package main;
 
@@ -940,10 +942,8 @@ KNX_Set($@) {
 	my $transval = KNX_checkAndClean($hash, $value, $targetGadName);	
 
 	#if cast not successful
-	if (!defined($transval))
-	{
-		return "invalid value: $value" if (!defined($transval));
-	}
+	return "invalid value: $value" if (!defined($transval));
+
 	#
 	#
 	#/process set command
@@ -1485,9 +1485,9 @@ KNX_limit ($$$$) {
 	my $factor = $dpttypes{$model}{FACTOR};
 	my $offset = $dpttypes{$model}{OFFSET};		
 	#get limits
-	my $min = $dpttypes{"$model"}{MIN};
-	my $max = $dpttypes{"$model"}{MAX};
-	
+	my $min = $dpttypes{$model}{MIN};
+	my $max = $dpttypes{$model}{MAX};
+
 	#only execute, if nummeric value
 	if (looks_like_number ($value))
 	{
@@ -1496,28 +1496,31 @@ KNX_limit ($$$$) {
 		{
 			if ($direction =~ m/^encode/i)
 			{
-				$retVal = $value / $factor if (defined ($factor));
-				$retVal = $value - $offset if (defined ($offset));			
+				#correct value
+				$retVal /= $factor if (defined ($factor));
+				$retVal -= $offset if (defined ($offset));		
 			}
 			elsif ($direction =~ m/^decode/i)
 			{
 				#correct value
-				$retVal = $value + $offset if (defined ($offset));
-				$retVal = $value * $factor if (defined ($factor));			
+				$retVal += $offset if (defined ($offset));
+				$retVal *= $factor if (defined ($factor));			
 			}			
 			
-			Log3 ($name, 5, "limit: FACTOR: $min" ) if (defined ($factor));
-			Log3 ($name, 5, "limit: OFFSET: $min" ) if (defined ($offset));
-			Log3 ($name, 5, "limit: scaled... Output: $retVal, Input: $value") if ($retVal != $value);
+			Log3 ($name, 5, "limit: FACTOR: $factor" ) if (defined ($factor));
+			Log3 ($name, 5, "limit: OFFSET: $offset" ) if (defined ($offset));
+			Log3 ($name, 5, "limit: scaled... Output: $retVal, Input: $value, Model: $model") if ($retVal != $value);
 		}
 		
+		#backup for later check
+		my $checkVal = $retVal;
 		#limitValue
-		$retVal = $min if (defined ($min) and ($value < $min));
-		$retVal = $max if (defined ($max) and ($value > $max));
+		$retVal = $min if (defined ($min) and ($retVal < $min));
+		$retVal = $max if (defined ($max) and ($retVal > $max));
 		
 		Log3 ($name, 5, "limit: MIN: $min" ) if (defined ($min));
-		Log3 ($name, 5, "limit: MAX: $min" ) if (defined ($max));
-		Log3 ($name, 5, "limit: casted... Output: $retVal, Input: $value" ) if ($retVal != $value);
+		Log3 ($name, 5, "limit: MAX: $max" ) if (defined ($max));
+		Log3 ($name, 5, "limit: casted... Output: $retVal, Input: $value, Model: $model" ) if ($checkVal != $value);
 	}
 	else
 	{