OPC UA
OPC UA (OPC Unified Architecture) is an industrial communication standard, defined in the multi-part IEC 62541 series published by the OPC Foundation, for exchanging data between PLCs, SCADA systems, sensors, and other industrial equipment across client/server and newer publish/subscribe models. Unlike older factory-floor protocols such as Modbus or BACnet, which assumed a physically isolated network and left authentication out entirely, OPC UA's IEC 62541-2 security model defines authentication, message signing, and encryption as built-in, configurable options an implementer can turn on -- though a server can still be deployed with security set to "none" for compatibility, so the standard supporting security doesn't guarantee a given deployment uses it. OPC UA also defines its own structured, self-describing information model, letting a client discover a device's variables and their types instead of relying on a fixed, externally documented register map the way Modbus does. It has become the preferred integration layer for newer industrial and building automation projects precisely because it gives operators a standards-based way to add the authentication older OT protocols never had, provided it's actually configured rather than left at its most permissive default.
By AdminKit team, Netbase JSC · Updated