IEC 62541-12:2025 PDF

IEC 62541-12:2025 specifies how OPC Unified Architecture (OPC UA) Clients and Servers interact with DiscoveryServers when used in different scenarios. It specifies the requirements for the LocalDiscoveryServer, LocalDiscoveryServer-ME and GlobalDiscoveryServer. It also defines information models for Certificate management, KeyCredential management and AuthorizationServices. Annex A informatively discusses deployment and configuration aspects. Annex B defines NodeSet and numeric NodeIds. Annex F provides installation rules for the LDS. Annex H compares the Certificate management defined in this document with IETF RFC 7030. This second edition cancels and replaces the first edition published in 2020. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) addition of a "Quantity Model" which can be referenced from EngineeringUnit Properties. The model defines quantities and assigned units. In addition it provides alternative units and the conversion to them; b) addition of rules for ValuePrecision Property: • can also be used for other subtypes like Duration and Decimal. • additional rules when ValuePrecision has negative values.