IEC 62541-11:2020 is available as
IEC
62541-11:2020 RLV which contains the International Standard and
its Redline version, showing all changes of the technical content
compared to the previous edition.
IEC 62541-11:2020 is part of the OPC Unified Architecture
standard series and defines the information model associated with
Historical Access (HA). It particularly includes additional and
complementary descriptions of the NodeClasses and Attributes needed
for Historical Access, additional standard Properties, and other
information and behaviour. The complete AddressSpace Model
including all NodeClasses and Attributes is specified in IEC
62541-3. The predefined Information Model is defined in IEC
62541-5. The Services to detect and access historical data and
events, and description of the ExtensibleParameter types are
specified in IEC 62541-4. This document includes functionality to
compute and return Aggregates like minimum, maximum, average etc.
The Information Model and the concrete working of Aggregates are
defined in IEC 62541-13. 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) a new
method for determining the first historical point has been added;
b) added clarifications on how to add, insert, modify, and delete
annotations.