diff --git a/fhem/CHANGED b/fhem/CHANGED
index 032571b0e..94249ed80 100644
--- a/fhem/CHANGED
+++ b/fhem/CHANGED
@@ -1,5 +1,10 @@
 # Add changes at the top of the list. Keep it in ASCII, and 80-char wide.
 # Do not insert empty lines here, update check depends on it.
+  - bugfix: 44_S7_ARead: event-on-change-reading
+  - bugfix: 44_S7_AWrite: event-on-change-reading
+  - bugfix: 44_S7_DRead: event-on-change-reading
+  - bugfix: 44_S7_DWrite: event-on-change-reading
+  - bugfix: 44_S7_S5Client.pm: loading serial modul
   - change:  89_FULLY: on-timer implemented
   - change:  77_SMAEM: V3.0.1, use abort cause of BlockingCall
   - change:  93_Log2Syslog: V3.2.0, add NOTIFYDEV (if possible)
diff --git a/fhem/FHEM/44_S7_ARead.pm b/fhem/FHEM/44_S7_ARead.pm
index 11d34a1ba..215f749c1 100644
--- a/fhem/FHEM/44_S7_ARead.pm
+++ b/fhem/FHEM/44_S7_ARead.pm
@@ -306,7 +306,7 @@ sub S7_ARead_Parse($$) {
 				}
 				else {
 					Log3 $name, 3,
-					  "$name S7_ARead: Parse unknown type : ("
+					  "$n S7_ARead: Parse unknown type : ("
 					  . $h->{DATATYPE} . ")";
 				}
 
@@ -333,7 +333,7 @@ sub S7_ARead_Parse($$) {
 				my @a;
 				if($attreocr) {
 					@a = split(/,/,$attreocr);
-					$hash->{".attreocr"} = \@a;
+					$h->{".attreocr"} = \@a;
 				}
 				# determine whether the reading is listed in any of the attributes
 				my @eocrv;
@@ -350,7 +350,7 @@ sub S7_ARead_Parse($$) {
 
 				  if($myI =~ m/([\d\.\-eE]+)/ && looks_like_number($1)) { #41083, #62190
 					my $mv = $1;
-					my $last_value = $hash->{".attreocr-threshold$reading"};
+					my $last_value = $h->{".attreocr-threshold$reading"};
 					if( !defined($last_value) ) {
 					  $h->{".attreocr-threshold$reading"} = $mv;
 					} elsif( abs($mv - $last_value) < $threshold ) {
diff --git a/fhem/FHEM/44_S7_AWrite.pm b/fhem/FHEM/44_S7_AWrite.pm
index ff61cd6dd..899508c06 100644
--- a/fhem/FHEM/44_S7_AWrite.pm
+++ b/fhem/FHEM/44_S7_AWrite.pm
@@ -475,7 +475,7 @@ sub S7_AWrite_Parse($$) {
 				my @a;
 				if($attreocr) {
 					@a = split(/,/,$attreocr);
-					$hash->{".attreocr"} = \@a;
+					$h->{".attreocr"} = \@a;
 				}
 				# determine whether the reading is listed in any of the attributes
 				my @eocrv;
@@ -492,7 +492,7 @@ sub S7_AWrite_Parse($$) {
 
 				  if($myI =~ m/([\d\.\-eE]+)/ && looks_like_number($1)) { #41083, #62190
 					my $mv = $1;
-					my $last_value = $hash->{".attreocr-threshold$reading"};
+					my $last_value = $h->{".attreocr-threshold$reading"};
 					if( !defined($last_value) ) {
 					  $h->{".attreocr-threshold$reading"} = $mv;
 					} elsif( abs($mv - $last_value) < $threshold ) {
diff --git a/fhem/FHEM/44_S7_DRead.pm b/fhem/FHEM/44_S7_DRead.pm
index 35beeabe1..5095b34ed 100644
--- a/fhem/FHEM/44_S7_DRead.pm
+++ b/fhem/FHEM/44_S7_DRead.pm
@@ -402,7 +402,7 @@ sub S7_DRead_Parse($$) {
 				my @a;
 				if($attreocr) {
 					@a = split(/,/,$attreocr);
-					$hash->{".attreocr"} = \@a;
+					$h->{".attreocr"} = \@a;
 				}
 				# determine whether the reading is listed in any of the attributes
 				my @eocrv;
@@ -419,7 +419,7 @@ sub S7_DRead_Parse($$) {
 
 				  if($valueText =~ m/([\d\.\-eE]+)/ && looks_like_number($1)) { #41083, #62190
 					my $mv = $1;
-					my $last_value = $hash->{".attreocr-threshold$reading"};
+					my $last_value = $h->{".attreocr-threshold$reading"};
 					if( !defined($last_value) ) {
 					  $h->{".attreocr-threshold$reading"} = $mv;
 					} elsif( abs($mv - $last_value) < $threshold ) {
diff --git a/fhem/FHEM/44_S7_DWrite.pm b/fhem/FHEM/44_S7_DWrite.pm
index 1918aa2d0..a51444581 100644
--- a/fhem/FHEM/44_S7_DWrite.pm
+++ b/fhem/FHEM/44_S7_DWrite.pm
@@ -478,7 +478,7 @@ sub S7_DWrite_setABit($$) {
 					my @a;
 					if($attreocr) {
 						@a = split(/,/,$attreocr);
-						$hash->{".attreocr"} = \@a;
+						$h->{".attreocr"} = \@a;
 					}
 					# determine whether the reading is listed in any of the attributes
 					my @eocrv;
@@ -495,7 +495,7 @@ sub S7_DWrite_setABit($$) {
 
 					  if($valueText =~ m/([\d\.\-eE]+)/ && looks_like_number($1)) { #41083, #62190
 						my $mv = $1;
-						my $last_value = $hash->{".attreocr-threshold$reading"};
+						my $last_value = $h->{".attreocr-threshold$reading"};
 						if( !defined($last_value) ) {
 						  $h->{".attreocr-threshold$reading"} = $mv;
 						} elsif( abs($mv - $last_value) < $threshold ) {
diff --git a/fhem/FHEM/44_S7_S5Client.pm b/fhem/FHEM/44_S7_S5Client.pm
index 37e5210ef..2cb10063d 100644
--- a/fhem/FHEM/44_S7_S5Client.pm
+++ b/fhem/FHEM/44_S7_S5Client.pm
@@ -477,13 +477,14 @@ sub S5ConnectPLCAS511($$) {
 	my $b1 = "";
 	my $ttyPort;
 
-	if ($^O=~/Win/) {
-		eval ("use Win32::SerialPort;");
+	if($^O =~ m/Win/) {
+		require Win32::SerialPort;
+		#eval ("use Win32::SerialPort;");
 		$self->{serial} = new Win32::SerialPort ($portName);
 	}else{
-		eval ("use Device::SerialPort;");
+		#eval ("use Device::SerialPort;");
+		require Device::SerialPort;
 		$self->{serial} = new Device::SerialPort ($portName);
-	}
 
 
 	main::Log3( undef, 3, "Can't open serial port $portName" )
diff --git a/fhem/FHEM/44_S7_S7Client.pm b/fhem/FHEM/44_S7_S7Client.pm
index f94e94a1a..6eb0865fb 100644
--- a/fhem/FHEM/44_S7_S7Client.pm
+++ b/fhem/FHEM/44_S7_S7Client.pm
@@ -334,7 +334,7 @@ sub new {
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 );
 	$self->{PDU}->{DATA} = "";
-
+	$self->{TCPClient} = undef;
 	return bless $self, $class;
 }