diff --git a/CHANGED b/CHANGED
index e1091bcfc..de0f71805 100644
--- a/CHANGED
+++ b/CHANGED
@@ -553,3 +553,5 @@
   - bugfix:  PachLog fixes from Axel
   - bugfix:  HOWTO/Examples revisited for correctness
   - bugfix:  DEFINED & INITIALIZED triggers.
+  - feature: 20_OWFS.pm support for passive Devices e.g. DS9097 (see commandref.html)
+  - bugfix:  21_OWTEMP.pm Defining a device now fail when no OWFS device was defined
diff --git a/FHEM/20_OWFS.pm b/FHEM/20_OWFS.pm
index d8dd0d8b5..9b470d5c3 100644
--- a/FHEM/20_OWFS.pm
+++ b/FHEM/20_OWFS.pm
@@ -30,6 +30,7 @@ use OW;
 
 my %models = (
   "DS1420"     => "",
+  "DS9097"     => "",
 );
 my %fc = (
   "1:DS9420"   => "01",
@@ -77,6 +78,8 @@ OWFS_Get($$)
   my ($hash,@a) = @_;
 
   return "argument is missing @a" if (@a != 2);
+  return "Passive Adapter defined. No Get function implemented."
+    if(!defined($hash->{OW_ID}));
   return "Unknown argument $a[1], choose one of " . join(",", sort keys %gets)
     if(!defined($gets{$a[1]}));
 
@@ -116,10 +119,12 @@ OWFS_DoInit($)
   my $path;
   my $ret;
 
-  $path = $hash->{OW_FAMILY}.".".$hash->{OWFS_ID};
+  if (defined($hash->{OWFS_ID})) {
+    $path = $hash->{OW_FAMILY}.".".$hash->{OWFS_ID};
  
-  foreach my $q (sort keys %gets) {
-    $ret = OWFS_GetData($hash,$q);
+    foreach my $q (sort keys %gets) {
+      $ret = OWFS_GetData($hash,$q);
+    }
   }
 
   $hash->{STATE} = "Initialized" if (!$hash->{STATE});  
@@ -137,7 +142,7 @@ OWFS_Define($$)
 
   my @a = split("[ \t][ \t]*", $def);
 
-  return "wrong syntax: define <name> OWFS <owserver:port> <model> <id>"
+  return "wrong syntax: define <name> OWFS <owserver:port> <model> [<id>]"
     if (@a < 2 && int(@a) > 5);
 
   my $name  = $a[0];
@@ -149,22 +154,24 @@ OWFS_Define($$)
   return "Define $name: wrong model: specify one of " . join ",", sort keys %models
     if (!grep { $_ eq $model } keys %models);
 
-  my $id     = $a[4];
-  return "Define $name: wrong ID format: specify a 12 digit value"
-    if (uc($id) !~ m/^[0-9|A-F]{12}$/); 
+  if (@a > 4) {
+    my $id     = $a[4];
+    return "Define $name: wrong ID format: specify a 12 digit value"
+      if (uc($id) !~ m/^[0-9|A-F]{12}$/); 
 
-  $hash->{FamilyCode} = \%fc;
-  my $fc = $hash->{FamilyCode};
-  if (defined ($fc)) {
-    foreach my $c (sort keys %{$fc}) {
-      if ($c =~ m/$model/) {
-        $hash->{OW_FAMILY} = $fc->{$c};
+    $hash->{FamilyCode} = \%fc;
+    my $fc = $hash->{FamilyCode};
+    if (defined ($fc)) {
+      foreach my $c (sort keys %{$fc}) {
+        if ($c =~ m/$model/) {
+          $hash->{OW_FAMILY} = $fc->{$c};
+        }
       }
     }
+    delete ($hash->{FamilyCode});
+    $hash->{OW_ID} = $id;
+    $hash->{OW_PATH} = $hash->{OW_FAMILY}.".".$hash->{OW_ID};
   }
-  delete ($hash->{FamilyCode});
-  $hash->{OW_ID} = $id;
-  $hash->{OW_PATH} = $hash->{OW_FAMILY}.".".$hash->{OW_ID};
 
   $hash->{STATE} = "Defined";
 
diff --git a/FHEM/21_OWTEMP.pm b/FHEM/21_OWTEMP.pm
index e797ca053..8676ba6bf 100644
--- a/FHEM/21_OWTEMP.pm
+++ b/FHEM/21_OWTEMP.pm
@@ -273,6 +273,8 @@ OWTEMP_Define($$)
   $defptr{$a[2]} = $hash;
   AssignIoPort($hash);
 
+  return "No I/O device found. Please define a OWFS device first."
+    if(!defined($hash->{IODev}->{NAME}));
   $hash->{LOCAL} = 2;
   OWTEMP_GetUpdate($hash,"");
   delete $hash->{LOCAL};
diff --git a/docs/commandref.html b/docs/commandref.html
index cfc7466a5..019ddc7c8 100644
--- a/docs/commandref.html
+++ b/docs/commandref.html
@@ -2876,7 +2876,7 @@ A line ending with \ will be concatenated with the next one, so long lines
   <a name="OWFSdefine"></a>
   <b>Define</b>
   <ul>
-    <code>define &lt;name&gt; OWFS &lt;owserver-ip:port&gt; &lt;model&gt; &lt;id&gt;</code>
+    <code>define &lt;name&gt; OWFS &lt;owserver-ip:port&gt; &lt;model&gt; [&lt;id&gt;]</code>
     <br><br>
 
     Define a 1-wire device to communicate with an OWFS-Server.<br><br>
@@ -2888,11 +2888,11 @@ A line ending with \ will be concatenated with the next one, so long lines
     <code>&lt;model&gt;</code>
     <ul>
       Define the <a href="#owfs_type">type</a> of the input device.
-      Currently supportet: <code>DS1420</code>
+      Currently supportet: <code>DS1420, DS9097 (for passive Adapter)</code>
     </ul>
     <code>&lt;id&gt;</code>
     <ul>
-      Corresponding to the <a href="#owfs_id">id</a> of the input device.
+      Corresponding to the <a href="#owfs_id">id</a> of the input device. Only for active Adapter.
       <br><br>
     </ul>
 
@@ -2902,7 +2902,13 @@ A line ending with \ will be concatenated with the next one, so long lines
 
     Example:
     <ul>
-      <code>define DS9490R OWFS 127.0.0.1:4304 DS1420 93302D000000</code><br>
+      <code>#define an active Adapter:<br>
+      define DS9490R OWFS 127.0.0.1:4304 DS1420 93302D000000</code><br>
+    </ul>
+    <br>
+    <ul>
+      <code>#define a passive Adapter:<br>
+      define DS9097 OWFS 127.0.0.1:4304 DS9097</code><br>
     </ul>
     <br>
   </ul>
@@ -2914,7 +2920,7 @@ A line ending with \ will be concatenated with the next one, so long lines
   <ul>
     <code>get &lt;name&gt; &lt;value&gt;</code>
     <br><br>
-    where <code>value</code> is one of:<br>
+    where <code>value</code> is one of (not supported by passive Devices e.g. DS9097):<br>
     <ul>
       <li><a name="owfs_address"></a>
         <code>address</code> (read-only)<br>
@@ -3030,7 +3036,7 @@ A line ending with \ will be concatenated with the next one, so long lines
 
     Example:
     <ul>
-      <code>define KG.hz.TF.01 OWTEMP 93302D000000 300 60</code><br>
+      <code>define KG.hz.TF.01 OWTEMP 14B598010800 300 60</code><br>
     </ul>
     <br>
   </ul>