// the find
epics-modules/opcua
EPICS Device Support for OPC UA
EPICS device support module that connects OPC UA servers to EPICS IOCs, letting control system engineers read/write PLC and SCADA data using standard EPICS records. Targets accelerator and large-scale scientific instrument facilities running EPICS Base 3.15 or 7. Narrow audience, but exactly what that audience needs.
Dual backend design (open62541 free SDK + Unified Automation commercial SDK) is well-structured — the abstraction layer in devOpcuaSup is clean and the two backends share the same interface without leaking implementation details. CI matrix covers Linux and Windows for both backends, so regressions get caught across the combinations that actually matter. The end-to-end test suite ships a real OPC UA test server built on open62541, not a mock — that's the right call for a protocol adapter. Binary distribution tars for common Linux distros mean you can skip the SDK build entirely if your distro matches.
open62541 1.4 is unsupported and UA SDK 1.8 is explicitly broken — both are current releases, so you're stuck on older SDK versions until those get fixed. Documentation is self-described as sparse: the main reference is a PDF requirements spec and a cheat sheet, neither of which is great for onboarding. 25 stars after what looks like years of active development signals this will not have a broad community to fall back on when you hit edge cases. The Unified Automation SDK dependency is a proprietary commercial library, which creates a licensing headache for anyone trying to distribute IOC binaries.