This complex VariableType is used to represent a Variable which contains one or more fields where each field is composed of one or more bits.

Subtypes of this VariableType shall have a DataType of UInteger or one of its subtypes. Its ValueRank shall be either Scalar (-1) or a single dimensional Array (1).

Each bit field defined by the BitFieldDefinitions shall also be exposed as a child DataVariable. The BrowseName of the DataVariable shall be the same as the BitFieldDefinition name field and the NamespaceIndex of the BrowseName shall be the same as the BitFieldDefinition name field’s NamespaceIndex.

Optional bit fields may be defined by using the Optional Modeling Rule for the child DataVariable which represents the bit field. An application accessing a BitFieldType with an optional bit field should determine the presence of the optional bit field by checking the instance of that BitFieldType for the presence of the child DataVariable which represents the optional field.

The VariableType is defined in Table 95.

Table 95 – BitFieldType definition

Attribute		Value
BrowseName		BitFieldType
IsAbstract		True
ValueRank		ScalarOrOneDimension
DataType		UInteger
References	NodeClass		BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the BaseDataVariableType defined in 7.4.
HasProperty	Variable		BitFieldsDefinitions	BitFieldDefinition[]	PropertyType	Mandatory
HasComponent	Variable		<FieldName>	BaseDataType	BaseVariableType	MandatoryPlaceholder
HasComponent	Variable		<OptionalFieldName>	BaseDataType	BaseVariableType	OptionalPlaceholder
Conformance Units