This property enables updating Tags inside an OPC Group. If this property is set to False, no Tag inside the OPC Group is updated. Otherwise, Tags with their AllowRead property set to True and in Advise mode (for more information, please check the AdviseType property) are kept updated according to OPC Group's update time (the Scan property) and dead band (the DeadBand property). If this property is set to False, users cannot use OPC Group's Refresh method.