Index: DamEngine/trunk/xsd/DamSensorGroup.xsd
===================================================================
diff -u -r1600 -r1620
--- DamEngine/trunk/xsd/DamSensorGroup.xsd	(.../DamSensorGroup.xsd)	(revision 1600)
+++ DamEngine/trunk/xsd/DamSensorGroup.xsd	(.../DamSensorGroup.xsd)	(revision 1620)
@@ -9,6 +9,6 @@
         </xs:complexType>
       </xs:element>
     </xs:sequence>
-    <xs:attribute name="Id" type="xs:int" />
+    <xs:attribute name="Id" type="xs:int" use="required" />
   </xs:complexType>
 </xs:schema>
\ No newline at end of file