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DataTypes

The dataTypes section allows you to define new types for OPC UA Variables. It is possible to define enumerations, custom structured structures (Extension Objects), or to overload one of the basic OPC UA dataTypes.

1. Enumeration​

OPC UA Enumerations represent discrete sets of named values. In Sterfive OPCUA Modeler, you can define enums using three different styles:

A. Simple List of Strings​

You can define an enumeration as a plain, compact list of strings. The compiler will automatically assign sequential integer values starting at 0:

Enumeration defined as a simple list of strings
dataTypes:
  - browseName: SoftwareVersionFileType
    enum: [Current, Pending, Fallback]

B. List of Structured Name Objects​

Alternatively, you can define an enumeration by listing structured name elements:

Enumeration defined as a list of structured name objects
dataTypes:
  - browseName: MachineStatus
    enum:
      - name: Idle
      - name: Running
      - name: Error

C. Explicit Names & Values (Hex or Dec Support)​

If you need non-sequential values or want to map specific numeric codes (e.g. for hardware flags or hex color codes), you can define explicit values:

Enumeration with custom names and explicit values
dataTypes:
  - browseName: ColorEnumType
    enum:
      - name: Red
        value: 0xFF0000
      - name: Blue
        value: 0x0000FF
      - name: Green
        value: 0x00FF00
Best Practices

To follow standard OPC UA companion specification design patterns, it is a recommended practice to append the Enumeration suffix to your custom enum type names (for example, DeviceHealthEnumeration).

D. Option sets (bit masks)​

An OptionSet is a set of flags held in one unsigned integer (OPC 10000-3 §5.8). Set isOptionSet: true, base it on ua:Byte, ua:UInt16, ua:UInt32 (the default) or ua:UInt64, and give each flag the mask of its bit, 1, 2, 4, 8, …, so flags combine with |:

An OptionSet
dataTypes:
  - browseName: PermissionsType
    subtypeOf: ua:UInt32
    isOptionSet: true
    enum:
      - name: Read
        value: 1
      - name: Write
        value: 2
      - name: Execute
        value: 8
        displayName: Run

Without values, the masks follow the order of the list (1, 2, 4, …). A value that is not a single bit, two flags on the same bit, or a bit beyond the width of the base type is an error. An enum on an unsigned integer without isOptionSet: true is an error too: it is always meant as an OptionSet.

A value of an OptionSet is written with its flags, combined with |. A list of flags or the number itself are accepted too, and so are the standard's own OptionSets (ua:AccessLevelType: CurrentRead | CurrentWrite). An unknown flag, or a number setting a bit no flag defines, is an error:

A value of an OptionSet
objectTypes:
  - browseName: DoorType
    components:
      - browseName: Access
        dataType: PermissionsType
        value: Read | Write

In the generated NodeSet, each field's Value is the bit position (Execute, mask 8, is Value="3"), and the OptionSetValues property names every bit, using displayName when one is given: the same shape as the standard's own AccessLevelType.

2. DataType Overrides (Subtyping Basic Types)​

You can overload or subtype basic OPC UA primitive data types (such as ua:String, ua:Double, etc.) to create semantic alias types.

For example, you can create a custom identifier type and then utilize it inside an ObjectType component:

Subtyping a basic string primitive
dataTypes:
  - browseName: MyIdentifierType
    subtypeOf: ua:String
Applying the semantic custom DataType in an ObjectType
objectTypes:
  - browseName: MyObjectType
    subtypeOf: ua:BaseObjectType
    components:
      - browseName: Identifier
        dataType: MyIdentifierType

3. Extension Objects (Custom Structured DataTypes)​

Extension Objects represent complex structured data types in OPC UA. You can define a custom structured type under the dataTypes section.

The modeler automatically infers that a custom data type is an ExtensionObject if you include a list of properties under the fields keyword.

Defining a ThreeDVector structured Extension Object
dataTypes:
  - browseName: ThreeDVector
    fields:
      - name: X
        dataType: ua:Float 
        description: the X value
      - name: Y
        dataType: ua:Float 
        description: the Y value
      - name: Z
        dataType: ua:Float 
        description: the Z value

Full example​

📄 Full working example — data-types.model.yaml
data-types.model.yaml
namespaceUri: http://sterfive.com/UA/doc-examples/datatypes/
version: 1.0.0
publicationDate: "2026-05-26T00:00:00Z"

dataTypes:
  - browseName: SoftwareVersionFileType
    enum: [Current, Pending, Fallback]

  - browseName: MachineStatus
    enum:
      - name: Idle
      - name: Running
      - name: Error

  - browseName: ColorEnumType
    enum:
      - name: Red
        value: 0xFF0000
      - name: Blue
        value: 0x0000FF
      - name: Green
        value: 0x00FF00

  - browseName: PermissionsType
    subtypeOf: ua:UInt32
    isOptionSet: true
    enum:
      - name: Read
        value: 1
      - name: Write
        value: 2
      - name: Execute
        value: 8
        displayName: Run

  - browseName: MyIdentifierType
    subtypeOf: ua:String

  - browseName: ThreeDVector
    fields:
      - name: X
        dataType: ua:Float 
        description: the X value
      - name: Y
        dataType: ua:Float 
        description: the Y value
      - name: Z
        dataType: ua:Float 
        description: the Z value

  - browseName: MotorInfoDataType
    fields:
      - name: Acceleration
        dataType: ua:Float 
        description: the motor acceleration
      - name: Velocity
        dataType: ua:Float 
        description: the motor velocity
      - name: Torque
        dataType: ua:Float 
        description: the Z value

  - browseName: ControllerDataType
    fields:
      - name: ControllerName
        dataType: ua:String
        description: Name of the controller

  - browseName: NestedMotorInfoDataType
    fields:
      - name: Motor
        dataType: ControllerDataType 
        description: the motor acceleration

objectTypes:
  - browseName: MyObjectType
    subtypeOf: ua:BaseObjectType
    components:
      - browseName: Identifier
        dataType: MyIdentifierType

  - browseName: DoorType
    components:
      - browseName: Access
        dataType: PermissionsType
        value: Read | Write
📄 Generated NodeSet2.xml — data-types.model.Nodeset2.xml
data-types.model.Nodeset2.xml
<?xml version="1.0"?>
<UANodeSet xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:uax="http://opcfoundation.org/UA/2008/02/Types.xsd" xmlns="http://opcfoundation.org/UA/2011/03/UANodeSet.xsd" xmlns:ns1="http://sterfive.com/UA/doc-examples/datatypes/Type.xsd">
    <NamespaceUris>
        <Uri>http://sterfive.com/UA/doc-examples/datatypes/</Uri>
    </NamespaceUris>
    <Models>
        <Model ModelUri="http://sterfive.com/UA/doc-examples/datatypes/" Version="1.0.0" PublicationDate="2026-05-26T00:00:00.000Z">
            <RequiredModel ModelUri="http://opcfoundation.org/UA/" Version="1.05.06" PublicationDate="2025-11-08T00:00:00.000Z"/>
        </Model>
    </Models>
    <Aliases>
        <Alias Alias="1:MyIdentifierType">ns=1;i=1006</Alias>
        <Alias Alias="EnumValueType">i=7594</Alias>
        <Alias Alias="HasComponent">i=47</Alias>
        <Alias Alias="HasEncoding">i=38</Alias>
        <Alias Alias="HasModellingRule">i=37</Alias>
        <Alias Alias="HasProperty">i=46</Alias>
        <Alias Alias="HasSubtype">i=45</Alias>
        <Alias Alias="HasTypeDefinition">i=40</Alias>
        <Alias Alias="LocalizedText">i=21</Alias>
    </Aliases>
<!--ReferenceTypes-->
<!--DataTypes-->
    <UADataType NodeId="ns=1;i=1000" BrowseName="1:SoftwareVersionFileType">
        <DisplayName>SoftwareVersionFileType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=29</Reference>
            <Reference ReferenceType="HasProperty">ns=1;i=1001</Reference>
        </References>
        <Definition Name="1:SoftwareVersionFileType">
            <Field Name="Current" Value="0"/>
            <Field Name="Pending" Value="1"/>
            <Field Name="Fallback" Value="2"/>
        </Definition>
    </UADataType>
    <UAVariable NodeId="ns=1;i=1001" BrowseName="EnumStrings" ParentNodeId="ns=1;i=1000" AccessLevel="3" ValueRank="1" ArrayDimensions="3" DataType="LocalizedText">
        <DisplayName>EnumStrings</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=68</Reference>
        </References>
        <Value>
            <ListOfLocalizedText xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
                <LocalizedText>
                    <Text>Current</Text>
                </LocalizedText>
                <LocalizedText>
                    <Text>Pending</Text>
                </LocalizedText>
                <LocalizedText>
                    <Text>Fallback</Text>
                </LocalizedText>
            </ListOfLocalizedText>
        </Value>
    </UAVariable>
    <UADataType NodeId="ns=1;i=1002" BrowseName="1:MachineStatus">
        <DisplayName>MachineStatus</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=29</Reference>
            <Reference ReferenceType="HasProperty">ns=1;i=1003</Reference>
        </References>
        <Definition Name="1:MachineStatus">
            <Field Name="Idle" Value="0"/>
            <Field Name="Running" Value="1"/>
            <Field Name="Error" Value="2"/>
        </Definition>
    </UADataType>
    <UAVariable NodeId="ns=1;i=1003" BrowseName="EnumStrings" ParentNodeId="ns=1;i=1002" AccessLevel="3" ValueRank="1" ArrayDimensions="3" DataType="LocalizedText">
        <DisplayName>EnumStrings</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=68</Reference>
        </References>
        <Value>
            <ListOfLocalizedText xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
                <LocalizedText>
                    <Text>Idle</Text>
                </LocalizedText>
                <LocalizedText>
                    <Text>Running</Text>
                </LocalizedText>
                <LocalizedText>
                    <Text>Error</Text>
                </LocalizedText>
            </ListOfLocalizedText>
        </Value>
    </UAVariable>
    <UADataType NodeId="ns=1;i=1004" BrowseName="1:ColorEnumType">
        <DisplayName>ColorEnumType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=29</Reference>
            <Reference ReferenceType="HasProperty">ns=1;i=1005</Reference>
        </References>
        <Definition Name="1:ColorEnumType">
            <Field Name="Red" Value="16711680"/>
            <Field Name="Blue" Value="255"/>
            <Field Name="Green" Value="65280"/>
        </Definition>
    </UADataType>
    <UAVariable NodeId="ns=1;i=1005" BrowseName="EnumValues" ParentNodeId="ns=1;i=1004" AccessLevel="3" ValueRank="1" DataType="EnumValueType">
        <DisplayName>EnumValues</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=68</Reference>
        </References>
        <Value>
            <ListOfExtensionObject xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
                <ExtensionObject>
                    <TypeId>
                        <Identifier>i=7616</Identifier>
                    </TypeId>
                    <Body>
                        <EnumValueType>
                            <Value>16711680</Value>
                            <DisplayName>
                                <Text>Red</Text>
                            </DisplayName>
                            <Description>
                                <Text/>
                            </Description>
                        </EnumValueType>
                    </Body>
                </ExtensionObject>
                <ExtensionObject>
                    <TypeId>
                        <Identifier>i=7616</Identifier>
                    </TypeId>
                    <Body>
                        <EnumValueType>
                            <Value>255</Value>
                            <DisplayName>
                                <Text>Blue</Text>
                            </DisplayName>
                            <Description>
                                <Text/>
                            </Description>
                        </EnumValueType>
                    </Body>
                </ExtensionObject>
                <ExtensionObject>
                    <TypeId>
                        <Identifier>i=7616</Identifier>
                    </TypeId>
                    <Body>
                        <EnumValueType>
                            <Value>65280</Value>
                            <DisplayName>
                                <Text>Green</Text>
                            </DisplayName>
                            <Description>
                                <Text/>
                            </Description>
                        </EnumValueType>
                    </Body>
                </ExtensionObject>
            </ListOfExtensionObject>
        </Value>
    </UAVariable>
    <UADataType NodeId="ns=1;i=1006" BrowseName="1:MyIdentifierType">
        <DisplayName>MyIdentifierType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=12</Reference>
        </References>
    </UADataType>
    <UADataType NodeId="ns=1;i=1007" BrowseName="1:ThreeDVector">
        <DisplayName>ThreeDVector</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=22</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1008</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1009</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1010</Reference>
        </References>
        <Definition Name="1:ThreeDVector">
            <Field Name="X" DataType="i=10">
                <Description>the X value</Description>
            </Field>
            <Field Name="Y" DataType="i=10">
                <Description>the Y value</Description>
            </Field>
            <Field Name="Z" DataType="i=10">
                <Description>the Z value</Description>
            </Field>
        </Definition>
    </UADataType>
    <UAObject NodeId="ns=1;i=1008" BrowseName="Default Binary">
        <DisplayName>Default Binary</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1009" BrowseName="Default XML">
        <DisplayName>Default XML</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1010" BrowseName="Default JSON">
        <DisplayName>Default JSON</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UADataType NodeId="ns=1;i=1011" BrowseName="1:MotorInfoDataType">
        <DisplayName>MotorInfoDataType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=22</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1012</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1013</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1014</Reference>
        </References>
        <Definition Name="1:MotorInfoDataType">
            <Field Name="Acceleration" DataType="i=10">
                <Description>the motor acceleration</Description>
            </Field>
            <Field Name="Velocity" DataType="i=10">
                <Description>the motor velocity</Description>
            </Field>
            <Field Name="Torque" DataType="i=10">
                <Description>the Z value</Description>
            </Field>
        </Definition>
    </UADataType>
    <UAObject NodeId="ns=1;i=1012" BrowseName="Default Binary">
        <DisplayName>Default Binary</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1013" BrowseName="Default XML">
        <DisplayName>Default XML</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1014" BrowseName="Default JSON">
        <DisplayName>Default JSON</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UADataType NodeId="ns=1;i=1015" BrowseName="1:ControllerDataType">
        <DisplayName>ControllerDataType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=22</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1016</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1017</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1018</Reference>
        </References>
        <Definition Name="1:ControllerDataType">
            <Field Name="ControllerName" DataType="i=12">
                <Description>Name of the controller</Description>
            </Field>
        </Definition>
    </UADataType>
    <UAObject NodeId="ns=1;i=1016" BrowseName="Default Binary">
        <DisplayName>Default Binary</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1017" BrowseName="Default XML">
        <DisplayName>Default XML</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1018" BrowseName="Default JSON">
        <DisplayName>Default JSON</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UADataType NodeId="ns=1;i=1019" BrowseName="1:NestedMotorInfoDataType">
        <DisplayName>NestedMotorInfoDataType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=22</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1020</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1021</Reference>
            <Reference ReferenceType="HasEncoding">ns=1;i=1022</Reference>
        </References>
        <Definition Name="1:NestedMotorInfoDataType">
            <Field Name="Motor" DataType="ns=1;i=1015">
                <Description>the motor acceleration</Description>
            </Field>
        </Definition>
    </UADataType>
    <UAObject NodeId="ns=1;i=1020" BrowseName="Default Binary">
        <DisplayName>Default Binary</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1021" BrowseName="Default XML">
        <DisplayName>Default XML</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
    <UAObject NodeId="ns=1;i=1022" BrowseName="Default JSON">
        <DisplayName>Default JSON</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=76</Reference>
        </References>
    </UAObject>
<!--ObjectTypes-->
<!--ObjectType - 1:MyObjectType {{{{ -->
    <UAObjectType NodeId="ns=1;i=1023" BrowseName="1:MyObjectType">
        <DisplayName>MyObjectType</DisplayName>
        <References>
            <Reference ReferenceType="HasSubtype" IsForward="false">i=58</Reference>
            <Reference ReferenceType="HasComponent">ns=1;i=1024</Reference>
        </References>
    </UAObjectType>
    <UAVariable NodeId="ns=1;i=1024" BrowseName="1:Identifier" ParentNodeId="ns=1;i=1023" AccessLevel="3" DataType="1:MyIdentifierType">
        <DisplayName>Identifier</DisplayName>
        <References>
            <Reference ReferenceType="HasTypeDefinition">i=63</Reference>
            <Reference ReferenceType="HasModellingRule">i=78</Reference>
        </References>
    </UAVariable>
<!--ObjectType - 1:MyObjectType }}}}-->
<!--VariableTypes-->
<!--Other Nodes-->
</UANodeSet>