--- a/plcopen/structures.py	Thu Dec 10 12:26:06 2009 +0100
+++ b/plcopen/structures.py	Thu Dec 10 16:37:11 2009 +0100
@@ -74,12 +74,12 @@
                         variable_name = "%s%d"%(type, block.getlocalId())
                     else:
                         variable_name = "%s%d_%s"%(type, block.getlocalId(), parameter)
-                    if generator.Interface[-1][0] != "VAR" or generator.Interface[-1][1] or generator.Interface[-1][2] or generator.Interface[-1][3]:
-                        generator.Interface.append(("VAR", False, False, False, []))
+                    if generator.Interface[-1][0] != "VAR" or generator.Interface[-1][1] is not None or generator.Interface[-1][2]:
+                        generator.Interface.append(("VAR", None, False, []))
                     if variable.connectionPointOut in generator.ConnectionTypes:
-                        generator.Interface[-1][4].append((generator.ConnectionTypes[variable.connectionPointOut], variable_name, None, None))
+                        generator.Interface[-1][3].append((generator.ConnectionTypes[variable.connectionPointOut], variable_name, None, None))
                     else:
-                        generator.Interface[-1][4].append(("ANY", variable_name, None, None))
+                        generator.Interface[-1][3].append(("ANY", variable_name, None, None))
                     if len(output_variables) > 1 and parameter not in ["", "OUT"]:
                         vars.append([(parameter, (generator.TagName, "block", block.getlocalId(), "output", i)), 
                                      (" => %s"%variable_name, ())])