ProSoft Technology PLX8X-MNET-61850 - Manual (Page 216)

Glossary of Terms PLX8x-MNET-61850 ♦ Communication Gateway
User Manual Modbus TCP/IP to IEC 61850
Page 216 of 228 ProSoft Technology, Inc.
May 14, 2014
Physical System
A system composed of the IEDs and the interconnecting physical communication
network (commonly fiber optics). The boundary of a system is given by its logical
or physical interfaces. Examples are industrial systems, management systems,
information systems, etc.
Piece of Information for Communication (PICOM)
PICOM is a description of an information transfer on a given logical connection
with given communication attributes between two logical nodes. It also contains
the information to be transmitted and required attributes, for example,
performance. It does not represent the actual structure or format of the data that
is transmitted over the communication network. The PICOM approach was
adopted from the CIGRE working group 34.03.
Point to Point
One-to-one communication link between two nodes, used only for
communication between those two nodes.
Positive Test
Test to ensure the correct implementation of the system capabilities as defined
by the supplier. A positive test has a described and defined response.
Presentation Layer
Layer 6 of the OSI reference model for Open Systems Interconnection. It
provides an interface between the concrete local syntax used by the Application
layer and the negotiated abstract and transfer syntaxes to be used for the
transfer of data during a communication session between the two communicating
application entities.
Primary System
Common term for all power system equipment and switchgear.
Process Level Functions
All functions interfacing to the process, i.e. binary and analog input/output
functions, for example: data acquisition (including sampling) and the issuing of
commands. These functions communicate via the logical interfaces 4 and 5 to
the bay level.
Process Related Station Level Functions
Functions that use data from more than one bay, or from the whole substation,
and act on the primary equipment of more than one bay, or on the primary
equipment of the whole substation. Examples of such functions are: station-wide
interlocking, automatic sequencers, and busbar protection. These functions
communicate mainly via the logical interface 8.