OPC UA Object Types
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OPC UA object types define class like structures in OPC UA namespace that can be instantiated and added to the server address space.
It is possible to create an instance of an object type by using the resource type Cybus::Node::OpcuaObject
Download:
---
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/'
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
_children
contains child objects in the OPC UA object tree
_value
contains the plain serialized value as JSON
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 } } } }
contains all metadata on a node. The nodeclass corresponds to the node-opcua Nodeclass enum documented here: > On nodes of type “Variable” the dataType entry indicates the OPC UA native data type documented here: >