Section 7 Logical node data modelGUID-EFBB8957-ABA9-4B25-B1CC-630B892A3FC7 v3The data model used by IEC 61850 is based on logical nodes containing a set ofdata objects. 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 sideand common data classes for the data object attributes. Also here it is given has theelements in these classes are defined as:• Mandatory (M)• Optional (O)• Conditional optional (Cxxx)• In addition, the IEC 61850 states rules for adding vendor-specific definitionsto the standard, in order to cope with extra functionality.The possible description of the data model according to the standard allows toadapt a logical node of a LN class to that what the product is supporting or usingfor this LN. This definition of what parts of a class is used in the actual product andpossible addition is called a type, according to IEC 61850-6. There are LN typesbased upon LN classes. The LN type attributes are called Data Objects (or DATA)and are in of DO types, base upon respective CDC class. This allows all partners inthe IEC 61850 project who need this LN to understand the LN in all details for thecommunication part.The IEC 61850 standard does not describe the functionality and way of operation.Each supplier has to describe this separately. ABB has described their functionblocks that represent a logical node and all other function blocks in the technicalmanuals. This chapter in the communication protocol manual has two purposes:• 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 nodeGUID-8400E43A-6199-4539-BB74-CAC865C85508 v5The IEC 61850 standard describes in part 7-5, 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 handlingof the data objects in the IEDs.1MRK 511 440-UEN A Section 7Logical node data modelSwitchgear control unit SAM600-IO Version 2.2 IEC 35Communication protocol manual