Use this property to specify the position an OPC UA Block Element occupies among the OPC UA Block Elements configured by the Size property of the OPC UA Block Tag in which it is inserted. This property accepts values from 0 (zero) to a number less than the value defined in Size. For example, when configuring an OPC UA Block Tag with its Size property equal to 20, the maximum valid number for this property is 19 and the minimum is 0 (zero). This property can be changed after communication starts. The default value of this property is 0 (zero), but when mapping OPC UA Block Elements of an OPC UA Block Tag, Elipse Water Studio automatically configures this property to a value according to the specified.