The WSAnalogUnitType is a subtype of the AnalogUnitType. It is used if the engineering unit can be transferred in addition to the value. As an example, the WS DataPoints from the measured values category can be mentioned. If an engineering unit is not defined in UNECE Recommendations N°. 20, the values in the EUInformation DataType must be filled in. See OPC 10000-8. The WSAnalogUnitType is required for compatibility with the WS Protocol, where the WS TagNumber is usually used to identify a WS DataPoint. In OPC UA the WS BrowseName shall be used as BrowseName for identification. Therefore the WSTagNumber property is optional.

It is formally defined in Table 23.

Table 23 – WSAnalogUnitType Definiton

Attribute	Value
BrowseName	WSAnalogUnitType
IsAbstract	False
ValueRank	-1 (-1 = Scalar)
DataType	BaseDataType
References	Node Class	BrowseName	DataType	TypeDefinition	Other
Subtype of the AnalogUnitType defined in OPC 10000-8
0:HasProperty	Variable	WSTagNumber	UInt16	0:PropertyType	O

Figure 19 – WSAnalogUnitType as Subtype of AnalogUnitType

OPC UA DataTypes