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Client Tutorials

These tutorials walk through the client-side features of o6 against a single, fixed example server that runs against a background simulation. Every snippet on every page assumes you can reach that server at opc.tcp://localhost:4840 and that its address space looks like the layout described in Set the Stage.

The pages build on each other — each one introduces one concept at a time and reuses the same server, so by the end you have walked through the full lifecycle: connecting, reading values, calling methods, subscribing to live data, reacting to state changes, and so on.

Start the server first

Save server.py and sim.py into the same folder, and leave the server running in its own terminal:

python server.py

Set the Stage walks through it, and lists every NodeId the pages below use.

Topics

The tutorials are organized around what you typically do with a client:

First Steps

  1. Connect / disconnect
  2. Browse
  3. Read / write value
  4. Call a method
  5. Node API syntax

Monitoring

  1. Monitor Datachange
  2. Subscriptions
  3. Modify a subscription
  4. Filter
  5. Listen to events

Client Configuration

  1. Security
  2. Application Description
  3. State Callbacks

Information Modeling

  1. Load packaged companion specs
  2. Load nodeset files
  3. NodeIds and namespace info
  4. Semantic Discovery

Advanced Topics

  1. Low-level service calls
  2. Async client

Beyond the tutorials

  • Client manual — the connected picture behind these pages: the two service layers, sync vs. async, lifecycle.
  • Node API — the object-oriented view of the address space.
  • API Reference — every public method and its signature.