IEC 62832-2-2020 Industrial-process measurement, control and automation – Digital factory framework – Part 2: Model elements (IEC 62832-2:2020)

IEC 62832-2-2020 Industrial-process measurement, control and automation – Digital factory framework – Part 2: Model elements (IEC 62832-2:2020). 3.3.3 Representation of the definition of model elements The template used in this document for representing the definition of model elements of the DF reference model is specified in Table 2. The upper part of the template provides the definition of a model element (identity and meaning). It is formatted as fields with respective values. Because these fields are intended to be used accordingly when the model elements will be registered in a ConceptDictionary, the fields use names of model elements defined in this document. The ItemCode and VersionIdentifier fields can be used to uniquely identify a model element within the DF framework. The structure of the model element is represented in the lower part of the template as a list of constituent elements. Depending on cardinality and conditions, each constituent element in the template may be instantiated as a constituent of the defined model element. Constituent elements inherited from the ParentModelElement are not listed. The field “Structure element” contains a reference to a model element definition. The constituent element is derived from the referenced model element definition. A constituent element may be defined as an instance of a model element or as a reference to an instance of a model element. The field “I/R” contains a text string (“I”, “R” or “I/R”), which indicates whether the constituent element is defined as an instance or as a reference: • the value “I” indicates that the structure contains an instance of the particular constituent element (or multiple instances depending on the value of the cardinality); • the value “R” indicates that the structure contains a reference to an instance of the particular constituent element (or multiple references depending on the value of the cardinality); • the value “I/R” indicates that the structure contains either an instance of or a reference to an instance of the particular constituent element (or multiple ones depending on the value of the cardinality). NOTE In the case of “I/R”, the use of an instance or a reference is decided by the actual implementation. The field “Cardinality” contains a range which defines the number of constituent elements, the range is expressed using the following convention: [a..b] where: a is the minimum number of constituent elements; b is the maximum number of constituent elements. EXAMPLE 1 The number of constituent...