fix Use of uninitialized value

74_AMAD.pm

@@ -1236,7 +1236,8 @@ sub AMAD_CommBridge_Read($) {
 
 
     
-    elsif ( $fhemcmd =~ /setreading\b/ ) {
+    if( defined($fhemcmd) and ($fhemcmd) ) {
+        if ( $fhemcmd =~ /setreading\b/ ) {
             my $tv = $data[1];
 
             Log3 $bname, 4, "AMAD ($bname) - AMAD_CommBridge: processing receive reading values - Device: $device Data: $tv";
@@ -1332,6 +1333,8 @@ sub AMAD_CommBridge_Read($) {
             return;
         }
     
+    }
+
 
     $response = "header lines: \r\n AMADCommBridge receive incomplete or corrupt Data\r\n FHEM to do nothing\r\n";
     $c = $hash->{CD};