Section 7 Logical node data modelThe data model used by IEC 61850 is based on logical nodes containing a set of dataobjects. The data model is defined in the standards.• IEC 61850-7-4 Compatible logical node classes and data classes• IEC 61850-7-3 Common data classesThe standard describes only classes of logical nodes and data objects on one side andcommon data classes for the data object attributes. The elements in these classes havecertain definitions.• Mandatory (M)• Optional (O)• Conditional optional (Cxxx)• In addition, IEC 61850 states rules for adding vendor-specific definitions to thestandard, in order to cope with extra functionality.The possible description of the data model according to the standard allows to adapta logical node of a LN class to that what the product is supporting or using for this LN.This definition of what parts of a class is used in the actual product and possibleaddition is called a type, according to IEC 61850-6. There are LN types based uponLN classes. The LN type attributes are called Data Objects (or DATA) and are in ofDO types, base upon respective CDC class. This allows all partners in the IEC 61850project who need this LN to understand the LN in all details for the communicationpart.The IEC 61850 standard does not describe the functionality and way of operation.Each supplier has to describe this separately. ABB has described their function blocksthat represent a logical node and all other function blocks in the technical manuals.This chapter in the communication protocol manual has two tasks:• Describe the Logical Node types and their data object attribute types.• Make the link to the description of the function block.7.1 Common data objects in each logical nodeThe IEC 61850 standard describes in part 7-4, a Common Logical Node. The dataobjects contained in that LN are both mandatory and optional. The mandatory dataobjects have to be included in each LN. This clause describes the general handling ofthe data objects within the 630 series products.1MRS756793 E Section 7Logical node data model630 series 37Communication Protocol Manual
