Overview – Echelon ISI User Manual

Page 4

ISI Programmer’s Guide

Overview

Control networks consist of intelligent devices like switches, thermostats, pumps,
motors, valves, controllers, and a variety of other sensors and actuators that

communicate with each other to provide distributed monitoring and control. A

control network may be a small, simple network consisting of a few devices; may
be a large network in a building, factory, or ship consisting of tens of thousands

of devices; or may even be a very large regional network consisting of millions of

devices. In every case, the devices in the network must be configured to become
part of a common network, and to exchange data amongst themselves. The

process of configuring devices in a control network to establish communication
among the devices is called

network installation

Networks can be categorized by the method used to perform network installation.
The two categories of networks are

managed networks

and

self-installed

networks. A managed network is a network where a shared

network

management server

is used to perform network installation. A user typically

uses a tool to interact with the server and define how the devices in the network

should be configured and how they should communicate. Such a tool is called a

network management tool

. For example, Echelon’s LonMaker

Integration Tool

is a network management tool that uses a network management server called the

LNS

Server to install devices in a network. Although a network management

tool and a server are used to initially establish network communication, they

need not be present all the time for the network to function. The network

management tool and server are only required whenever changes are made to the
network’s configuration.

In a managed network, the network management tool and server allocate various

network resources, such as device and data point addresses. The network
management server is also aware of the network topology, and can configure

devices for optimum performance within the constraints of the topology.

The alternative to a managed network is a self-installed network. There is no

central tool or server that manages all of the network configuration in a self-
installed network. Instead, each device contains code that replaces parts of the

network management server’s functionality, resulting in a network that no

longer requires a special tool or server to establish network communication or to
change the configuration of the network.

Devices in a self-installed network cannot rely on a network management server
to coordinate their configuration. Since each device is responsible for its own
configuration, a common standard is required to ensure that devices configure

themselves in a compatible way. The standard protocol for performing self-

installation in L

ORKS

networks is called the

ORKS

Interoperable Self-

Installation (ISI) Protocol

. The ISI protocol can be used for networks of up to 200

devices that meet topology and connection constraints described in this guide.

Larger or more complex networks must either be installed as managed networks,
or must be partitioned into multiple smaller subsystems, where each subnetwork

has no more than 200 devices and meets the ISI topology and connection

constraints. Devices that conform to the L

ORKS

ISI protocol are called

ISI

devices