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