Roadmap › Industrial Automation — PLC, SCADA, Modbus and OPC UA › Module: Supervisory Systems and Communication
Lessons in this course (10)
8. OPC UA — the standard for IT/OT data exchange
Advanced★ Must knowLesson 8 of 10
OPC UA (Unified Architecture, IEC 62541) is a platform-independent, secure, service-oriented standard for industrial data exchange — the successor of classic OPC DA, which depended on Windows DCOM.
| Feature | Meaning |
|---|---|
| Information model | Address space of nodes (objects, variables, methods) with types and references — data has meaning, not just addresses |
| Services | Browse, Read, Write, Subscribe (monitored items notify on change), Call methods, history read, alarms & conditions |
| Security | X.509 certificates, signing and encryption, user authentication (username, certificate, token) |
| Transports | Binary over TCP (opc.tcp://host:4840), HTTPS; PubSub over UDP/MQTT for one-to-many |
| Companion specifications | Standard models per industry/machine type (PackML, Robotics, Machine Tools/umati, Euromap for plastics) |
Many PLCs (Siemens S7-1500, Beckhoff, B&R, CODESYS) include an OPC UA server; gateways such as Kepware expose older protocols as OPC UA.