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Note: The following is an excerpt from the official IEC catalog. It is provided here as a convenience and is not authoritative. Refer to the original document as the authoritative reference.

IEC 62541-5:2020 defines the Information Model of the OPC Unified Architecture. The Information Model describes standardized Nodes of a Server’s AddressSpace. These Nodes are standardized types as well as standardized instances used for diagnostics or as entry points to server-specific Nodes. Thus, the Information Model defines the AddressSpace of an empty OPC UA Server. However, it is not expected that all Servers will provide all of these Nodes. This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:

a) Added Annex F on User Authentication. Describes the Role Information Model that also allows configuration of Roles.

b) Added new data types:

1. Union
2. Decimal
3. OptionSet
4. DateString
5. TimeString
6. DurationString
7. NormalizedString
8. DecimalString
9. AudioDataType

c) Added Method to request a state change in a Server.

d) Added Method to set Subscription to persistent mode.

e) Added Method to request resending of data from a Subscription.

f) Added concept allowing to temporarily create a file to write to or read from a server in C.4.

g) Added new Variable type to support Selection Lists.

h) Added optional properties to FiniteStateMachineType to expose currently available states and transitions.

i) Added UrisVersion Property to ServerType. This version information can be used for session-less service invocation.

See also:

• IEC 62541-001 OPC Unified Architecture - Part 1: Overview and concepts
• IEC 62541-002 OPC Unified Architecture - Part 2: Security Model
• IEC 62541-003 OPC Unified Architecture - Part 3: Address Space Model
• IEC 62541-004 OPC Unified Architecture - Part 4: Services
• IEC 62541-006 OPC Unified Architecture - Part 6: Mappings
• IEC 62541-007 OPC Unified Architecture - Part 7: Profiles
• IEC 62541-008 OPC Unified Architecture - Part 8: Data Access
• IEC 62541-009 OPC Unified Architecture - Part 9: Alarms and Conditions
• IEC 62541-010 OPC Unified Architecture - Part 10: Programs
• IEC 62541-011 OPC Unified Architecture - Part 11: Historical Access
• IEC 62541-012 OPC Unified Architecture - Part 12: Discovery and global
• IEC 62541-013 OPC Unified Architecture - Part 13: Aggregates
• IEC 62541-014 OPC Unified Architecture - Part 14: PubSub
• IEC 62541-100 OPC Unified Architecture - Part 100: Device Interface