Nodedefinitions are specified using tables (see Table 2).

Attributesare defined by providing the Attributename and a value, or a description of the value.

Referencesare defined by providing the ReferenceTypename, the BrowseNameof the TargetNodeand its NodeClass.

  • If the TargetNodeis a component of the Nodebeing defined in the table the Attributesof the composed Nodeare defined in the same row of the table.
  • The DataTypeis only specified for Variables; “[<number>]” indicates a single-dimensional array, for multi-dimensional arrays the expression is repeated for each dimension (e.g. [2][3] for a two-dimensional array). For all arrays the ArrayDimensionsis set as identified by <number> values. If no <number> is set, the corresponding dimension is set to 0, indicating an unknown size. If no number is provided at all the ArrayDimensionscan be omitted. If no brackets are provided, it identifies a scalar DataTypeand the ValueRankis set to the corresponding value (see OPC 10000-3). In addition, ArrayDimensionsis set to null or is omitted. If it can be Any or ScalarOrOneDimension, the value is put into “{<value>}”, so either “{Any}” or “{ScalarOrOneDimension}” and the ValueRankis set to the corresponding value (see OPC 10000-3) and the ArrayDimensionsis set to null or is omitted. Examples are given in Table 1.

Table 1– Examples of DataTypes

Notation

DataType

ValueRank

ArrayDimensions

Description

0:Int32

0:Int32

-1

omitted or null

A scalar Int32.

0:Int32[]

0:Int32

1

omitted or {0}

Single-dimensional array of Int32 with an unknown size.

0:Int32[][]

0:Int32

2

omitted or {0,0}

Two-dimensional array of Int32 with unknown sizes for both dimensions.

0:Int32[3][]

0:Int32

2

{3,0}

Two-dimensional array of Int32 with a size of 3 for the first dimension and an unknown size for the second dimension.

0:Int32[5][3]

0:Int32

2

{5,3}

Two-dimensional array of Int32 with a size of 5 for the first dimension and a size of 3 for the second dimension.

0:Int32{Any}

0:Int32

-2

omitted or null

An Int32 where it is unknown if it is scalar or array with any number of dimensions.

0:Int32{ScalarOrOneDimension}

0:Int32

-3

omitted or null

An Int32 where it is either a single-dimensional array or a scalar.

If the NodeIdof a DataTypeis provided, the symbolic name of the Noderepresenting the DataTypeshall be used.

Note that if a symbolic name of a different namespace is used, it is prefixed by the NamespaceIndex(see 3.3.2.2).

Nodesof all other NodeClassescannot be defined in the same table; therefore, only the used ReferenceType, their NodeClassand their BrowseNameare specified. A reference to another part of this document points to their definition.

Table 2illustrates the table. If no components are provided, the DataType, TypeDefinition and Other columns may be omitted and only a Comment column is introduced to point to the Nodedefinition.

Table 2– Type Definition Table

Attribute

Value

Attribute name

Attribute value. If it is an optional Attribute that is not set "--" is used.

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

ReferenceTypename

NodeClassof the target Node.

BrowseNameof the target Node.

DataType of the referenced Node, only applicable for Variables.

TypeDefinitionof the referenced Node, only applicable for Variablesand Objects.

Additional characteristics of the TargetNodesuch as the ModellingRuleor AccessLevel.

NOTE Notes referencing footnotes of the table content.

Components of Nodescan be complex that is containing components by themselves. The TypeDefinition, NodeClassand DataType can be derived from the type definitions, and the symbolic name can be created as defined in 3.3.3.1. Therefore, those containing components are not explicitly specified; they are implicitly specified by the type definitions.

The Other column defines additional characteristics of the Node. Examples of characteristics that can appear in this column are show in Table 3.

Table 3– Examples of Other Characteristics

Name

Short Name

Description

0:Mandatory

M

The Nodehas the Mandatory ModellingRule.

0:Optional

O

The Nodehas the Optional ModellingRule.

0:MandatoryPlaceholder

MP

The Nodehas the MandatoryPlaceholder ModellingRule.

0:OptionalPlaceholder

OP

The Nodehas the OptionalPlaceholder ModellingRule.

ReadOnly

RO

The AccessLevelhas the CurrentReadbit set but not the CurrentWritebit.

ReadWrite

RW

The AccessLevelhas the CurrentReadand CurrentWritebits set.

WriteOnly

WO

The AccessLevelhas the CurrentWritebit set but not the CurrentReadbit.

If multiple characteristics are defined, they are separated by commas. The name or the short name may be used.

Each Nodedefined in this specification has ConformanceUnitsdefined in 11.1that require the Nodeto be in the AddressSpace. If a Serversupports a ConformanceUnit, it shall expose the Nodesrelated to the ConformanceUnitin its AddressSpace. If two Nodesare exposed, all Referencesbetween the Nodesdefined in this specification shall be exposed as well.

The relations between Nodesand ConformanceUnitsare defined at the end of the tables defining Nodes, one row per ConformanceUnit. The ConformanceUnitis reflected with a Category element in the UANodeSetfile (see OPC 10000-6).

The Nodesdefined in a table are not only the Nodedefined on top level, for example an ObjectType, but also the Nodesthat are referenced, as long as they are not defined in other tables. For example, the ObjectType TopologyElementTypedefines its InstanceDeclarationsin the same table, so the InstanceDeclarationsare also bound to the ConformanceUnitsdefined for the table. The table even indirectly defines additional InstanceDeclarationsas components of the top-level InstanceDeclarations, that are not directly visible in the table. The TypeDefinitionsand DataTypesused in the InstanceDeclarations, and the ReferenceTypesare defined in their individual tables and not in the table itself, therefore they are not bound to the ConformanceUnitsof the table.

To provide information about additional References, the format as shown in Table 4is used.

Table 4– <some>Type Additional References

SourceBrowsePath

Reference Type

Is Forward

TargetBrowsePath

SourceBrowsePath is always relative to the TypeDefinition. Multiple elements are defined as separate rows of a nested table.

ReferenceTypename

True = forward Reference.

TargetBrowsePath points to another Node, which can be a well-known instance or a TypeDefinition. You can use BrowsePathshere as well, which is either relative to the TypeDefinitionor absolute.

If absolute, the first entry needs to refer to a type or well-known instance, uniquely identified within a namespace by the BrowseName.

Referencescan be to any other Node.

To provide information about sub-components, the format as shown in Table 5is used.

Table 5– <some>Type Additional Subcomponents

BrowsePath

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

BrowsePath is always relative to the TypeDefinition. Multiple elements are defined as separate rows of a nested table

NOTE Same as for Table 2

The type definition table provides columns to specify the values for required Node Attributesfor InstanceDeclarations. To provide information about additional Attributes, the format as shown in Table 6is used.

Table 6– <some>Type Attribute values for child Nodes

BrowsePath

<Attribute name> Attribute

BrowsePath is always relative to the TypeDefinition. Multiple elements are defined as separate rows of a nested table

The values of Attributesare converted to text by adapting the reversible JSON encoding rules defined in OPC 10000-6.

If the JSON encoding of a value is a JSON string or a JSON number then that value is entered in the value field. Double quotes are not included.

If the DataTypeincludes a NamespaceIndex(QualifiedNames, NodeIdsor ExpandedNodeIds) then the notation used for BrowseNamesis used.

If the value is an Enumerationthe name of the enumeration value is entered.

If the value is a Structurethen a sequence of name and value pairs is entered. Each pair is followed by a newline. The name is followed by a colon. The names are the names of the fields in the DataTypeDefinition.

If the value is an array of non-Structuresthen a sequence of values is entered where each value is followed by a newline.

If the value is an array of Structuresor a Structurewith fields that are arrays or with nested Structuresthen the complete JSON array or JSON object is entered.

There can be multiple columns to define more than one Attribute.