diff --git a/fhem/FHEM/70_SCIVT.pm b/fhem/FHEM/70_SCIVT.pm
index cd4f743f2..134f1e286 100644
--- a/fhem/FHEM/70_SCIVT.pm
+++ b/fhem/FHEM/70_SCIVT.pm
@@ -5,6 +5,11 @@ use strict;
 use warnings;
 use Device::SerialPort;
 
+my %sets = (
+  "cmd"       => "",
+  "freq"      => "",
+);
+
 #####################################
 sub
 SCIVT_Initialize($)
@@ -14,7 +19,8 @@ SCIVT_Initialize($)
 # Consumer
   $hash->{DefFn}   = "SCIVT_Define";
   $hash->{GetFn}   = "SCIVT_Get";
-  $hash->{AttrList}= "model:SCD loglevel:0,1,2,3,4,5,6";
+  $hash->{SetFn}   = "SCIVT_Set";
+  $hash->{AttrList}= "model:SCD10,SCD20,SCD30 loglevel:0,1,2,3,4,5,6";
 }
 
 #####################################
@@ -34,105 +40,181 @@ SCIVT_Define($$)
     if($dev eq "none");
 
   if($dev ne "none") {
-    Log 2, "SCIVT opening device $dev";
+    Log 3, "SCIVT opening device $dev";
     my $po = new Device::SerialPort ($dev);
-    return "Can't open $dev: $!" if(!$po);
+    return "SCIVT Can't open $dev: $!" if(!$po);
     Log 2, "SCIVT opened device $dev";
     $po->close();
   }
 
   $hash->{DeviceName} = $dev;
+  $hash->{Timer} = 900; # call every 15 min
+  $hash->{Cmd} = 'F';   # get all data,  min/max unchanged
 
+  my $tn = TimeNow();
+  $hash->{READINGS}{"freq"}{TIME} = $tn;
+  $hash->{READINGS}{"freq"}{VAL} = $hash->{Timer};
+  $hash->{READINGS}{"cmd"}{TIME} = $tn;
+  $hash->{READINGS}{"cmd"}{VAL} = $hash->{Cmd};
+  $hash->{CHANGED}[0] = "freq: $hash->{Timer}";
+  $hash->{CHANGED}[1] = "cmd: $hash->{Cmd}";
+
+  # InternalTimer blocks if init_done is not true
+  my $oid = $init_done;
+  $init_done = 1;
   SCIVT_GetStatus($hash);
+  $init_done = $oid;
   return undef;
 }
+#####################################
+sub
+SCIVT_Set($@)
+{
+my ($hash, @a) = @_;
+ return "\"set SCIVT\" needs at least two parameter" if(@a < 3);
+my $name = $hash->{NAME};
+Log GetLogLevel($name,4), "SCIVT Set request $a[1] $a[2], old: Timer:$hash->{Timer} Cmd: $hash->{Cmd}"; 
 
+return "Unknown argument $a[1], choose one of " . join(" ", sort keys %sets)
+  	if(!defined($sets{$a[1]}));
+
+$name = shift @a;
+my $type = shift @a;
+my $arg = join("", @a);
+my $tn = TimeNow();
+
+if($type eq "freq") 
+   { 
+   if ($arg > 0)
+      {
+      $hash->{Timer} = $arg * 60; 
+      $hash->{READINGS}{$type}{TIME} = $tn;
+      $hash->{READINGS}{$type}{VAL} = $hash->{Timer};
+      $hash->{CHANGED}[0] = "$type: $hash->{Timer}";
+      }
+   }
+
+if($type eq "cmd") 
+   { 
+   if ($arg eq "F")
+      {
+      $hash->{Cmd} = 'F'; 	# F : get all data
+      }
+   if ($arg eq "L")		# L : get all data and clear min-/max values
+      {
+      $hash->{Cmd} = 'L'; 
+      }
+   $hash->{READINGS}{$type}{TIME} = $tn;
+   $hash->{READINGS}{$type}{VAL} = $hash->{Cmd};
+   $hash->{CHANGED}[0] = "$type: $hash->{Cmd}";
+   }
+
+DoTrigger($name, undef) if($init_done);
+
+Log GetLogLevel($name,3), "SCIVT Set result Timer:$hash->{Timer} sec Cmd:$hash->{Cmd}";  
+return "SCIVT => Timer:$hash->{Timer} Cmd:$hash->{Cmd}";
+}
 
 #####################################
 sub
 SCIVT_Get($@)
 {
-  my ($hash, @a) = @_;
+my ($hash, @a) = @_;
+return "get for an SCIVT device needs exactly one parameter" if(@a != 2);
+my $name = $hash->{NAME};
 
-  return "get for an SCIVT device needs exactly one parameter" if(@a != 2);
+my $v;
+if($a[1] eq "data") 
+   {
+   $v = SCIVT_GetLine($hash->{DeviceName}, $hash->{Cmd});
+   if(!defined($v)) 
+      {
+      Log GetLogLevel($name,2), "SCIVT Get $a[1] error";
+      return "$a[0] $a[1] => Error";
+      }
+   $v =~ s/[\r\n]//g;                          # Delete the NewLine
+   $hash->{READINGS}{$a[1]}{VAL} = $v;
+   $hash->{READINGS}{$a[1]}{TIME} = TimeNow();
+   }
+else 
+   {
+   if($a[1] eq "param") 
+      {
+      $v = "$hash->{DeviceName} $hash->{Timer} $hash->{Cmd}";
+      }
+   else
+      {
+      return "Unknown argument $a[1], must be data or param";
+      }
+   }
 
-  my $v;
-  if($a[1] eq "data") {
-    $v = SCIVT_GetLine($hash->{DeviceName});
-    $v =~ s/[\r\n]//g;                          # Delete the NewLine
-  } else {
-    return "Unknown argument $a[1], must be data";
-  }
-
-  $hash->{READINGS}{$a[1]}{VAL} = $v;
-  $hash->{READINGS}{$a[1]}{TIME} = TimeNow();
-
-  return "$a[0] $a[1] => $v";
+Log GetLogLevel($name,3), "SCIVT Get $a[1] $v";
+return "$a[0] $a[1] => $v";
 }
 
 #####################################
 sub
 SCIVT_GetStatus($)
 {
-  my ($hash) = @_;
+my ($hash) = @_;
+my $dnr = $hash->{DEVNR};
+my $name = $hash->{NAME};
 
-  # Call us in 5 minutes again.
-  InternalTimer(gettimeofday()+300, "SCIVT_GetStatus", $hash, 0);
+# Call us in n minutes again.
+InternalTimer(gettimeofday()+ $hash->{Timer}, "SCIVT_GetStatus", $hash,1);
 
-  my $dnr = $hash->{DEVNR};
-  my $name = $hash->{NAME};
+my %vals;
+my $result = SCIVT_GetLine($hash->{DeviceName}, $hash->{Cmd});
 
-  my %vals;
-  my $result = SCIVT_GetLine($hash->{DeviceName});
+if(!defined($result)) 
+   {
+   Log GetLogLevel($name,4), "SCIVT read error, retry $hash->{DeviceName}, $hash->{Cmd}";
+   $result = SCIVT_GetLine($hash->{DeviceName}, $hash->{Cmd});
+   }
 
-  if(!defined($result)) 
-    {
-    Log GetLogLevel($name,2), "SCIVT read error, retry";
-    $result = SCIVT_GetLine($hash->{DeviceName});
-    }
+if(!defined($result)) 
+   {
+   Log GetLogLevel($name,2), "SCIVT read error, abort $hash->{DeviceName}, $hash->{Cmd}";
+   $hash->{STATE} = "timeout";
+   return $hash->{STATE};
+   }
+if (length($result) < 10)
+   {
+   Log GetLogLevel($name,2), "SCIVT incomplete line ($result)";
+   $hash->{STATE} = "incomplete";
+   }
+else
+   {
+   $result =~ s/^.*R://;
+   $result =~ s/[\r\n ]//g;   
+   Log GetLogLevel($name,3), "SCIVT $result (raw)";
+   $result=~ s/,/./g;
+   my @data = split(";", $result);
 
-  if(!defined($result)) 
-    {
-    Log GetLogLevel($name,2), "SCIVT read error, abort";
-    $hash->{STATE} = "timeout";
-    return $hash->{STATE};
-    }
-  if (length($result) < 10)
-    {
-    Log GetLogLevel($name,2), "SCIVT incomplete line ($result)";
-    $hash->{STATE} = "incomplete";
-    }
-  else
-    {
-    $result =~ s/^.*R://;
-    $result =~ s/[\r\n ]//g;   
-    Log GetLogLevel($name,2), "SCIVT $result (raw)";
-    $result=~ s/,/./g;
-    my @data = split(";", $result);
-    
-    my @names = ("Vs", "Is", "Temp", "minV", "maxV", "minI", "maxI");
-    my $tn = TimeNow();
-    for(my $i = 0; $i < int(@names); $i++) {
+   my @names = ("Vs", "Is", "Temp", "minV", "maxV", "minI", "maxI");
+   my $tn = TimeNow();
+   for(my $i = 0; $i < int(@names); $i++) 
+      {
       $hash->{CHANGED}[$i] = "$names[$i]: $data[$i]";
       $hash->{READINGS}{$names[$i]}{TIME} = $tn;
       $hash->{READINGS}{$names[$i]}{VAL} = $data[$i];
-    }
-    
-    DoTrigger($name, undef) if($init_done);
+      }
 
-    $result =~ s/;/ /g;  
-    $hash->{STATE} = "$result";
-    }
+   DoTrigger($name, undef) if($init_done);
 
-  return $hash->{STATE};
+   $result =~ s/;/ /g;  
+   $hash->{STATE} = "$result";
+   }
+
+return $hash->{STATE};
 }
 
 #####################################
 sub
-SCIVT_GetLine($)
+SCIVT_GetLine($$)
 {
-  my $retry = 0;
-  my ($dev) = @_;
+my $retry = 0;
+my ($dev,$cmd) = @_;
 
   return "R:13,66; 0,0;30;13,62;15,09;- 0,2; 2,8;\n"
         if($dev eq "none");       # Fake-mode
@@ -152,7 +234,7 @@ SCIVT_GetLine($)
   my $rm = "SCIVT timeout reading the answer";
   my $data="";
 
-  $serport->write('F');
+  $serport->write($cmd);
   sleep(1);
 
   for(;;)