lmxopcua/gr/layout.md

Galaxy Repository Object Layout

Object Hierarchy

Galaxy objects are organized in a tree hierarchy. The root is the Galaxy itself (ZB), with objects nested under areas and other containers:

ZB (Galaxy)
├── UnassignedArea
├── DEV
│   ├── DevAppEngine
│   ├── DevPlatform
│   └── TestArea [TestArea]
│       └── DevTestObject
│           ├── TestChildObject [TestChildObject]
│           ├── TestMachine_001
│           ├── DelmiaReceiver_001 [DelmiaReceiver]
│           └── MESReceiver_001 [MESReceiver]

Objects have a tag_name (instance name, e.g. TestMachine_001) and optionally a contained_name shown in brackets (the template/type, e.g. [DelmiaReceiver]). Parent-child containment defines the deployment and organizational structure.

Contained Name vs Tag Name

Each child object has a contained_name (its local name within its parent) and a globally unique tag_name. When browsing the hierarchy, we want to see the contained name path; when referencing tags at runtime, the tag_name is used.

Hierarchy Path (contained names)	Tag Reference (tag_name)
TestMachine_001.DelmiaReceiver.DownloadPath	DelmiaReceiver_001.DownloadPath
TestMachine_001.MESReceiver.MoveInBatchID	MESReceiver_001.MoveInBatchID

The contained_name (DelmiaReceiver) is the human-readable name scoped to its parent, while the tag_name (DelmiaReceiver_001) is the system-assigned globally unique name. Translation between the two is needed when going from a hierarchy browse to tag-level data access.

Target OPC UA Server Structure

The OPC UA server should mirror the Galaxy hierarchy using contained names for folder/container structure. Attributes appear as tags within their object's container, and child objects appear as sub-containers. When an OPC UA client reads/writes a tag value, the contained name path is translated to the tag_name reference.

ZB/
└── DEV/
    └── TestArea/
        └── TestMachine_001/
            ├── MachineID              → reads/writes TestMachine_001.MachineID
            ├── MachineCode            → reads/writes TestMachine_001.MachineCode
            ├── DelmiaReceiver/
            │   ├── DownloadPath       → reads/writes DelmiaReceiver_001.DownloadPath
            │   ├── JobStepNumber      → reads/writes DelmiaReceiver_001.JobStepNumber
            │   ├── PartNumber         → reads/writes DelmiaReceiver_001.PartNumber
            │   └── RecipeDownloadFlag → reads/writes DelmiaReceiver_001.RecipeDownloadFlag
            └── MESReceiver/
                ├── MoveInBatchID      → reads/writes MESReceiver_001.MoveInBatchID
                ├── MoveInCompleteFlag → reads/writes MESReceiver_001.MoveInCompleteFlag
                ├── MoveInFlag         → reads/writes MESReceiver_001.MoveInFlag
                └── ...

Folders (ZB, DEV, TestArea) are structural — they organize the browse tree but don't have tags. Containers (TestMachine_001, DelmiaReceiver, MESReceiver) hold both attributes (tags) and potentially child containers.

Tag (Attribute) View

Tags represent the data attributes exposed by objects. They are referenced in a flattened dot-notation format using the tag_name:

<tag_name>.<AttributeName>

Examples:

• TestMachine_001.MachineID
• TestMachine_001.MachineCode
• MESReceiver_001.MoveInBatchID
• MESReceiver_001.MoveInCompleteFlag
• MESReceiver_001.MoveInJobSequenceNumber
• DelmiaReceiver_001.DownloadPath
• DelmiaReceiver_001.JobStepNumber
• DelmiaReceiver_001.PartNumber
• DelmiaReceiver_001.RecipeDownloadFlag

This flat view collapses the hierarchy — all attributes across all objects appear as tag_name.AttributeName regardless of where the object sits in the containment tree.