A conceptual OPC UA documentation project showing how selected machine data can move from PLC-based machine systems to SCADA, historians, MES, dashboards, databases, and IT/OT systems through controlled and documented communication paths.
This project focuses on OPC UA server/client roles, structured machine data modeling, safe tag exposure, communication matrices, firewall rule examples, and access-control principles.
The purpose of this project is to document a simplified OPC UA-based machine data flow for a PLC-controlled production environment.
The project demonstrates how production data can be exposed in a structured and controlled way without giving uncontrolled direct access to PLCs or machine networks.
- OPC UA Server / Client architecture
- PLC-to-SCADA and PLC-to-MES data flow
- OPC UA Address Space and structured machine data
- Safe exposure of selected PLC and machine data
- Read, Subscribe, and Limited Write access
- Communication matrix documentation
- Firewall rule examples
- Access control and secure IT/OT exchange
Machine Cell Zone
PLC / HMI / Drives / Robot
↓
OT Production Zone
SCADA / Historian / OPC UA Server
↓
Industrial DMZ
OPC UA Gateway / Data Broker
↓
IT / MES Layer
MES / Database / Dashboard
| Component | Role | Example Systems |
|---|---|---|
| OPC UA Server | Provides selected structured data | PLC, gateway, SCADA, edge device, data broker |
| OPC UA Client | Reads, subscribes to, or writes selected values | SCADA, historian, MES, dashboard, database connector |
Important principle:
Server provides data.
Client consumes data.
Client may write only selected values if explicitly allowed and validated.
| Category | Example Data | Purpose |
|---|---|---|
| Status | Running, FaultActive, Mode, AlarmCode | Monitoring and alarms |
| Production | PartCounter, RejectCounter, CycleTime | Production tracking |
| Energy | PowerConsumption, Current, Voltage | Energy monitoring |
| Robot | RobotReady, RobotFault, ProgramNumber | Robot status |
| MES Context | OrderNumber, RecipeNumber, BatchNumber | Traceability and production context |
- Architecture Overview
- Data Flow Explanation
- Address Space and Data Model
- Security and Access Control
- Assumptions and Limitations
- OPC UA Communication Matrix
- Exposed Machine Data
- Firewall Rule Examples
This is a conceptual documentation project. It is not a deployable plant design.
Real implementations require plant-specific validation, vendor-specific configuration, cybersecurity review, certificate management, firewall validation, change management, and operational approval.