IEC 62451-8:2015 is part of the overall OPC Unified Architecture (OPC UA) standard series and defines the information model associated with Data Access (DA). It particularly includes additional VariableTypes and complementary descriptions of the NodeClasses and Attributes needed for Data Access, additional Properties, and other information and behaviour. This second edition cancels and replaces the first edition published in 2011 and constitutes a technical revision. This edition includes the following changes: - Clarified that deadband has to be between 0.0 and 100.0. Violations result in error Bad_DeadbandFilterInvalid; - Added VariableTypes handling ArrayItems and DataTypes supporting this, including complex number types.