OPC UA allows information to be represented as complex Variables (Variable with nested sub-variable) and/or as complex DataTypes, where a DataType has a structure or other special meaning associated with it. Each of the nested Variables can have a value that represents a simple base DataType such as an Integer or can represent a custom DataType such as a Currency or a structure.

The format of a value is represented by Attributes of Variables. This standard maps all value formats defined in ISA-95 into those attributes.