Information modelling is a fundamental concept in the field of computer science and information systems. It involves the process of representing and organizing information in a structured manner, enabling efficient storage, retrieval, and manipulation of data.

One of the key objectives of information modelling is to create a conceptual representation of real-world entities, their attributes, and the relationships between them. This is typically achieved through the use of formal languages, such as entity-relationship model ⁽¹⁾, UML (Unified Modeling Language ⁽²⁾), or domain-specific modelling languages.

In IEC SC3D, information model is combined with a meta model, EXPRSSS schema, data formats　etc.　IEC 61360-1 ⁽³⁾ specifies a meta model to implement the Common Data Dictionary of IEC CDD, IEC 61360-2 ⁽⁴⁾ provides EXPRESS ⁽⁵⁾ schema of IEC CDD which is shared with those defined in ISO 13584-42 ⁽⁶⁾, and IEC 62656-1 ⁽⁷⁾ specifies a tabular data format and a MOF (Meta-object Facility ⁽⁸⁾) structure to create the data dictionary of IEC CDD. IEC 62656-1 is partially harmonized with ISO 13584-25.

The simplified meta model of IEC 61360-1 is illustrated in Figure　1. With this meta model, the information modeling of IEC SC3D focuses on a common data dictionary defining a hierarchical structure for organizing data elements, starting from the highest level of abstraction down to the most detailed level. It categorizes data elements (i.e., dictionary element) into different classes and subclasses, allowing for a systematic and modular approach to data definition.

Furthermore, a data dictionary incorporates a range of data attributes and properties that describe the characteristics and behavior of each data element. These attributes, i.e., metadata, include data type, units of measurement, valid value ranges, and relationships with other data elements. By providing these metadata, IEC CDD enhances the understanding and usability of the defined data elements, which as a result contributes to the machine-interoperable data dictionary of IEC CDD.