Draft61850-7-4©1EC:2002 -9- 57WG10-12(61850-7-4)R3.0/FD1S INTRODUCTION This document is part of a set of specifications.The complete set of specifications defines a layered substation communication architecture.This architecture has been chosen to provide abstract definitions of classes and services such that the specifications are independent of specific protocol stacks,implementations,and operating systems.The mapping of these abstract classes and services to communication stacks is outside the scope of part IEC 61850-7-x and may be found in part IEC 61850-8-x and -9-x. IEC 61850-7-1 gives an overview of this communication architecture.The part IEC 61850-7-3 defines common attribute types and common data classes related to substation applications. The attributes of the common data classes may be accessed using services defined in IEC 61850-7-2.These common data classes are used in part IEC 61850-7-4 to define the compatible data classes To reach interoperability all data to be exchanged need a strong definition with regard to syntax and semantic.The semantic of the data is mainly provided by names assigned to logical nodes and data they contain as defined in the part IEC 61850-7-4. It should be noted that data with full semantic is only one of the elements required to achieve interoperability.Since data and services are hosted by devices (IED)a proper device model is needed along with compatible,domain specific services(see IEC 61850-7-2). The compatible logical node name and data name definitions found in this part and the associated semantic are fixed.The syntax of the type definitions of all data classes are abstract definitions provided in part IEC 61850-7-2 and-7-3 of this standard.Not all features of logical nodes are listed in part IEC 61850-7-4 e.g.data sets and logs are covered in part 1EC61850-7-2. Version 3.0:22.August 2002Draft 61850-7-4  IEC: 2002 – 9 – 57/WG10-12(61850-7-4)R3.0/FDIS Version 3.0: 22. August 2002 INTRODUCTION This document is part of a set of specifications. The complete set of specifications defines a layered substation communication architecture. This architecture has been chosen to provide abstract definitions of classes and services such that the specifications are independent of specific protocol stacks, implementations, and operating systems. The mapping of these abstract classes and services to communication stacks is outside the scope of part IEC 61850-7-x and may be found in part IEC 61850-8-x and -9-x. IEC 61850-7-1 gives an overview of this communication architecture. The part IEC 61850-7-3 defines common attribute types and common data classes related to substation applications. The attributes of the common data classes may be accessed using services defined in IEC 61850-7-2. These common data classes are used in part IEC 61850-7-4 to define the compatible data classes. To reach interoperability all data to be exchanged need a strong definition with regard to syntax and semantic. The semantic of the data is mainly provided by names assigned to logical nodes and data they contain as defined in the part IEC 61850-7-4. It should be noted that data with full semantic is only one of the elements required to achieve interoperability. Since data and services are hosted by devices (IED) a proper device model is needed along with compatible, domain specific services (see IEC 61850-7-2). The compatible logical node name and data name definitions found in this part and the associated semantic are fixed. The syntax of the type definitions of all data classes are abstract definitions provided in part IEC 61850-7-2 and -7-3 of this standard. Not all features of logical nodes are listed in part IEC 61850-7-4 e.g. data sets and logs are covered in part IEC 61850-7-2