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IDProjectCategoryView StatusDate SubmittedLast Update
000851910000-005: Information ModelApi Changepublic2022-12-07 18:312023-04-18 18:47
ReporterFrank Volkmann Assigned ToFrank Volkmann  
PrioritynormalSeverityfeatureReproducibilityhave not tried
Status assignedResolutionopen 
Summary0008519: Object Serialization as custom data structure variable
Description

General Value for Objects representing the Submodel of the Object as custom DataType

  • All Variables and Properties below the object instance following all hierarchical (or client) references as a structured datavariable.
  • Inverse references will not be followed.
  • The content will be defined by a temporary datatypedefinition referenced from that object via a hasDataType reference.
  • Some filter mechanisms will be needed, potentially flags on nodes can be used,
    Discussion results on the F2F, also follow the recording an/or meeting minutes of the meeting:
  • A proposal is discussed where the DTD is not referenced but is included as a new attribute.
  • Another discussion is that a well defined variable referenced by the object instance contains the value of the Object. This approach will not touch the object itsef and filters can potentially added easier.
  • Requirement is raised from different groups already

The discussion is not ended and the proposal has to be more detailed, I think a taskforce of the OPC UA WG can do a deeper discussion and thamn present a more finished proposal.

Steps To Reproduce

Proposed Workflow: Automatically …
...Create temporary data type representing the submodel*) of the object
...Extend NodeClass for Objects with a Value Attribute (or another new attribute)
...Add DataType definition reference for temporary data type (Step 1) to each Node instance
New „HasDataTypeDefinition“ reference connects the Object instance to the temporary DataType definition node
Changes in the Object‘s Submodel will immediately result in a change of the temporary DataType definition

The workflow will started when the object instance is read or subscribed.
Remind, that the DTD will change every time the sub-structure of the object (it's childs) will change.

Additional Information

This is the initial proposal proposed on the virtual OPC UA F2F on 2022-12-7.
The shown slides will be attached to the mantis issue.
The Description above already contains some results of the discussion in the meeting.

Proposal (and need for a solution) is initially from PNO OPC JWG. We run in that problem when we discuss' to publish sub-models and don't want to loose the deep structure of this information. So the flat list of Pub Sub is not a satisfying solution.
Today it's possible to fulfill our need manually be creating a custom data type and a special variable of that type that contains the information.The problem is, that this is a manual and pre-thought process you cannot do "just in time"

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Commit Version
Fix Due Date

Activities

Jim Luth

2022-12-07 18:51

administrator   ~0018269

Proposal Value Attribute for objects.pptx (1,272,066 bytes)

Jim Luth

2023-04-18 18:47

administrator   ~0019211

Frank will work with a team to develop a proposal.

Issue History

Date Modified Username Field Change
2022-12-07 18:31 Frank Volkmann New Issue
2022-12-07 18:51 Jim Luth Note Added: 0018269
2022-12-07 18:51 Jim Luth File Added: Proposal Value Attribute for objects.pptx
2023-04-18 16:04 Jim Luth Severity minor => feature
2023-04-18 18:44 Jim Luth Project Feature Requests => 10000-005: Information Model
2023-04-18 18:44 Jim Luth Category Feature Request => Api Change
2023-04-18 18:47 Jim Luth Assigned To => Frank Volkmann
2023-04-18 18:47 Jim Luth Status new => assigned
2023-04-18 18:47 Jim Luth Note Added: 0019211