OpenOpcUa Runtime Model Architecture

OpenOpcUa / OOUAMiddleware is a model-driven OPC UA execution engine designed since 2012 to interpret NodeSet models at runtime.
It is not a code-first SDK server and not an Information Model Compiler (IMC) system.
It is a runtime-interpreted industrial middleware architecture.

OpenOpcUa / OOUAMiddleware – Runtime NodeSet Architecture (Since 2012) NodeSet Model Layer Types • Instances • Historian Config • Alarm Config • Methods OOUAMiddleware Runtime Core Runtime Model Interpreter • Dynamic Loading • Model / Runtime Separation VPI Virtual Protocol Interface Connectivity / Acquisition (OT & IT) +100 VPIs parallel VFI Virtual File Interface Historian / Archiving / Services +10 VFIs parallel LUA Engine Multi-rate Scripts Simulation / Orchestration / Method Logic Middleware Layering – LineMiddleware → PlantMiddleware → Enterprise Industrial Assets PLC • CNC • Robots • Equipment IT / Cloud Connectivity MQTT • Cloud • Edge Gateways Files / Streams CSV • Parquet • Logs RDBMS / TSDB PostgreSQL • SQL Server • Timeseries Data Lake / Analytics Pipelines • BI • AI/ML

OpenOpcUa Runtime Model Architecture with VPI / VFI and embedded LUA execution.

NodeSet as the Source of Truth

In OpenOpcUa:

  • Types are loaded at runtime
  • Instances are loaded at runtime
  • Alarm configuration is declarative
  • Historian configuration is declarative
  • Methods are declared in NodeSet and implemented via LUA or VPI

There is:

  • No model compilation
  • No code generation
  • No static type binding

The runtime interprets the model directly.

NodeSet Model Layer

  • Types (Standard + Custom)
  • Instances (Plant / Line / Assets)
  • Alarm configuration
  • Historian configuration
  • Methods

The NodeSet is the authoritative contract.

OOUAMiddleware Runtime Core

  • Runtime model interpreter
  • Dynamic AddressSpace construction
  • Strong Model / Runtime separation
  • No recompilation required

VPI – Virtual Protocol Interfaces

  • Industrial protocol connectivity
  • PLC, CNC, Robots, Equipment
  • MQTT, Cloud, Edge connectivity
  • Scalable: +100 VPIs in parallel

VPI decouple acquisition from the model.

VFI – Virtual File Interfaces

  • Historian engines
  • CSV, Streams, Files
  • RDBMS / TSDB
  • Data lake integration
  • Scalable: +10 VFIs in parallel

VFI execute storage services independently from model logic.

Embedded LUA Engine

  • Multi-rate execution
  • Simulation
  • Orchestration
  • OPC UA Method implementation

Model-Driven Method Execution

In the ProductionCell demo:

  • The method InjectFault is declared in the NodeSet.
  • The method is implemented in LUA.
  • The runtime binds it dynamically.
  • Alarm conditions are evaluated declaratively.
  • Events are generated automatically.

Flow:
NodeSet Method → Runtime → LUA → Variable Update → A&C Engine → Event → Historian
This demonstrates strict separation between:

  • Model
  • Execution logic
  • Functional services

Architectural Positioning

CapabilityCode-First SDKIMCOpenOpcUa
Runtime Type Loading✖✖✔
Runtime Instance Loading✖✖✔
NodeSet as Source of Truth✖Partial✔
Declarative Alarm ConfigurationRareLimited✔
Declarative Historian ConfigurationRareLimited✔
Embedded Scripting✖✖✔
Runtime Model Evolution✖✖✔
Industrial Plug-In ArchitectureLimitedLimited✔

OpenOpcUa is not a generic OPC UA server.
It is a model-driven industrial OPC UA middleware engine capable of interpreting complete NodeSet models at runtime.
This architecture has been part of OOUAMiddleware since 2012.