OPC UA Object Types

OPC UA object types define class like structures in OPC UA namespace that can be instantiated and added to the server address space.

For more information on OPC UA Object Types, see the OPC Foundation Reference.

It is possible to create an instance of an object type by using the resource type Cybus::Node::OpcuaObject

Service Commissioning File Example

1KB

opcua-objecttype-example.yml

Open

---
description: demo for OPC UA objecttype nodes

metadata:
  name: OPC UA Objecttypes demo

resources:
  opcuaServer:
    type: Cybus::Server::Opcua
    properties:
      hostname: 192.168.178.46
      securityModes: ['None', 'SignAndEncrypt']
      nodesetFiles: ['di', 'machinery', 'ia', 'machineTool']
      securityPolicies: ['None', 'Basic256Sha256']
      allowAnonymous: true
      port: 4841

  parentNodeRoot:
    type: Cybus::Node::Opcua
    properties:
      parent: !ref opcuaServer
      browseName: cybus
      nodeId: ns=1;s=cybus
      nodeType: Object

  #######################################################
  #
  # Sample of an insance of an
  # machine tool type. The type "MachineToolType" is
  # defined in the MachineTool Umati namespace
  #
  #######################################################
  testMachineToolType:
    type: Cybus::Node::OpcuaObject
    properties:
      parent: !ref parentNodeRoot
      browseName: MyMachineToolTypeTest
      objectTypeName: MachineToolType
      sourceNamespaceUrl: 'http://opcfoundation.org/UA/MachineTool/'

Output Format

The server provides the structure of the object types and its values as a JSON structure as the example:

{
  'ObjectTypeSample':
    {
      '_children':
        {
          'OperationMode':
            {
              '_children':
                {
                  'ChildExample':
                    { '_children': {}, '_metadata': { 'nodeClass': 'Variable', 'dataType': 'Int64' }, '_value': '1883344340925958233434349340394' },
                },
            },
          '_metadata': { 'nodeClass': 'Variable', 'dataType': 'Int32' },
          '_value': 0,
        },
    },
  '_metadata': { 'nodeClass': 'Object' },
}

_metadata	contains all metadata on a node. The nodeclass corresponds to the node-opcua Nodeclass enum documented here: http://node-opcua.github.io/api_doc/2.0.0/enums/nodeclass.html> On nodes of type “Variable” the dataType entry indicates the OPC UA native data type documented here: http://node-opcua.github.io/api_doc/2.0.0/enums/datatype.html>
_children	contains child objects in the OPC UA object tree
_value	contains the plain serialized value as JSON

Writing Updates

Writing updates to the OPC UA object type can be achieved by publishing to the <ObjectNodeName>/write topic. The same JSON structure can be used with updated data in the _value items. For data updates on U/INT64 please review the section on BigInt datatypes in OPC UA Server documentation. It is not necessary to update the complete structure. You can also only write a JSON structure that contains the direct value update. To update all values for the example structure above, only the following structure would be required:

{ 'ObjectTypeSample': { '_children': { 'OperationMode': { '_children': { 'ChildExample': { '_value': '50000000000000' } }, '_value': 10 } } } }