diff -r 441f31474b50 -r 8350222a81c3 dialogs/FBDVariableDialog.py
--- a/dialogs/FBDVariableDialog.py	Fri Jun 14 10:52:08 2013 +0200
+++ b/dialogs/FBDVariableDialog.py	Fri Jun 14 10:54:21 2013 +0200
@@ -51,12 +51,13 @@
 
 class FBDVariableDialog(BlockPreviewDialog):
 
-    def __init__(self, parent, controller, tagname):
+    def __init__(self, parent, controller, tagname, exclude_input=False):
         """
         Constructor
         @param parent: Parent wx.Window of dialog for modal
         @param controller: Reference to project controller
         @param tagname: Tagname of project POU edited
+        @param exclude_input: Exclude input from variable class selection
         """
         BlockPreviewDialog.__init__(self, parent, controller, tagname,
               size=wx.Size(400, 380), title=_('Variable Properties'))
@@ -112,9 +113,10 @@
               flag=wx.ALIGN_RIGHT|wx.BOTTOM|wx.LEFT|wx.RIGHT)
         
         # Set options that can be selected in class combo box
-        for choice in VARIABLE_CLASSES_DICT.itervalues():
-            self.Class.Append(choice)
-        self.Class.SetStringSelection(VARIABLE_CLASSES_DICT[INPUT])
+        for var_class, choice in VARIABLE_CLASSES_DICT.iteritems():
+            if not exclude_input or var_class != INPUT:
+                self.Class.Append(choice)
+        self.Class.SetSelection(0)
         
         # Extract list of variables defined in POU
         self.RefreshVariableList()