Echelon OpenLNS Commissioning Tool - Manual (Page 21)

OpenLNS CT User’s Guide 5
OpenLNS CT Drawing
An OpenLNS CT drawing contains the graphical representation of the L ON W ORKS network. An
OpenLNS CT drawing consists of one or more drawing files, and the drawing files consist of one or
more pages that each represent a subsystem. One drawing file is designated as the top-level drawing
file; this drawing file is the one created when you create a new OpenLNS CT network design. A
subsystem within the top-level drawing file is designated as the top-level subsystem; this subsystem is
represented by the first page of the drawing that you create when you create a new OpenLNS CT
network design.
An OpenLNS CT drawing is always located on the computer running OpenLNS CT or on a remote file
share. When multiple OpenLNS CT users are accessing the same OpenLNS CT drawing, OpenLNS
CT automatically keeps the drawing synchronized. Multiple-user operation is described in Automatic
OpenLNS CT Drawing Synchronization in Chapter 7.
L
ON
W
ORKS
Basics
This section provides an overview of L ON W ORKS networks and defines related terms. The Glossary in
Appendix B provides a quick reference for specific terms.
Networks
A L ON W ORKS network consists of intelligent devices (such as sensors, actuators, and controllers) that
communicate with each other using a common protocol over one or more channels. Network devices
are sometimes called nodes.
Devices
Each device includes one or more processors and a transceiver. The processor(s) provide the device’s
intelligence and implement the ISO/IEC
14908-1 Control Network Protocol (CNP). The transceiver
serves as the device’s electrical interface to the communications channel.
Protocol
A device publishes and consumes information as instructed by the application that it is running. The
applications on different devices are not synchronized, and it is possible that multiple devices may all
try to talk at the same time. Meaningful transfer of information between devices on a network,
therefore, requires organization in the form of a set of rules and procedures. These rules and
procedures are the communication protocol, which may be referred to simply as the protocol. The
protocol defines the format of the messages being transmitted between devices and defines the actions
expected when one device sends a message to another. The protocol normally takes the form of
embedded software or firmware code in each device on the network. The CNP
is an open protocol
defined by the ISO/IEC 14908-1 standard (defined nationally in the United States, Europe, and China
by the ANSI/EIA 709.1, EN 14908, and GB/Z 20177 standards, respectively).
Device Templates
A device template contains all the attributes of a given device type, such as its functional blocks,
network variables, and configuration properties.
Channels
A channel is the physical media between devices upon which the devices communicate. The Control
Network Protocol is media independent; therefore, numerous types of media can be used for channels
such as twisted pair, power line, fiber optics, IP, and radio frequency (RF). Channels are categorized
into channel types, and the channel types are characterized by the device transceiver. Common
channel types include TP/FT-10 (ISO/IEC 14908-2 twisted pair free topology channel), TP/XF-1250