DescriptionTermChange of process data or an OPC internal value. Normally, anevent consists of value, quality, and timestamp.EventA physical IEC 61850 device that behaves as its own commu-nication node in the IEC 61850 protocol.Intelligent Electronic DeviceRepresentation of a group of functions. Each function is definedas a logical node. A physical device consists of one or severalLDs.Logical Device; LDThe smallest part of a function that exchanges data. An LN isan object defined by its data and methods.Logical Node; LNSeries of standards specifications aiming at open connectivityin industrial automation and the enterprise systems that supportindustry.OPCRepresentation of a connection to the data source within theOPC server. An OPC item is identified by a string