Views

Path: Views (standard OPC UA Views folder, ns=0;i=87)

4 OPC UA views that provide filtered perspectives of the address space. Views allow clients to browse only a subset of nodes relevant to a specific use case.

Available Views

OperatorView

Contains the nodes most relevant to a plant operator:

• Dynamic -- live process values (counters, waveforms, status)
• Methods -- callable actions
• Alarms -- active alarm conditions

Excludes: raw data types, structures, historical data, access control test nodes.

EngineeringView

Contains the entire TestServer folder. Equivalent to browsing without a view, but structured as a view for testing view-based browsing.

HistoricalView

Contains only the Historical folder with the 4 historical variables. Useful for clients that need to focus on trend data.

DataView

Contains:

• DataTypes -- all scalar, array, and matrix variables
• Structures -- all structured objects

Excludes: dynamic variables, methods, events, alarms.

How to Use Views

Browsing with a view

When calling the Browse or BrowseNext service, pass the view's NodeId in the View parameter of the BrowseDescription:

BrowseDescription {
    NodeId: <starting node>,
    View: {
        ViewId: <OperatorView NodeId>,
        Timestamp: null,
        ViewVersion: 0
    },
    ...
}

Only nodes that belong to the specified view will be returned.

Finding view NodeIds

1. Browse the Views folder (ns=0;i=87)
2. The child nodes are the 4 views
3. Each view has a NodeId (auto-generated, ns=1;i=XXXX)
4. Use that NodeId in subsequent browse calls

Testing Views

Basic view browsing

1. Browse the Views folder -> find 4 view nodes
2. Read each view's BrowseName attribute to identify them
3. Browse from Objects using OperatorView -> should only see Dynamic, Methods, Alarms under TestServer

View vs no-view comparison

1. Browse TestServer without a view -> see all 8+ sub-folders
2. Browse TestServer with OperatorView -> see only 3 sub-folders
3. Browse TestServer with DataView -> see only 2 sub-folders

Verifying view isolation

1. Browse with HistoricalView starting from TestServer
2. Try to navigate to DataTypes -> should not be reachable
3. Navigate to Historical -> should work, with all 4 variables visible

View completeness

1. Browse with EngineeringView from TestServer
2. Recursively browse all nodes -> should match the result of browsing without any view