Echelon Mini FX - Manual (Page 29)

16 Introduction
communications processor, or it may handle both application processing and
communications processing on the host processor. The Mini kit supports some of the
common tasks occurring in the creation of host-based devices; however, an additional
host-based device development tool, such as the ShortStack
® FX or the FTXL™
Developer’s Kit combined with a host development tool, is required.
Each device includes one or more processors that implement the ISO/IEC 14908-1
Control Network Protocol (CNP). Each device also includes a transceiver to provide its
interface to the communications channel.
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).
Channels
A channel is the physical media between devices upon which the devices communicate.
The CNP is media independent; therefore, numerous types of media can be used for
channels: twisted pair, power line, fiber optics, IP, and radio frequency (RF) to name a
few. 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 (high-speed twisted
pair channel), PL-20 (ISO/IEC 14908-3 power line channel), FO-20 (ANSI/CEA-709.4
fiber optics channel), and IP-852 (ISO/IEC 14908-4 IP-communication).
Different transceivers may be able to interoperate on the same channel; therefore, each
transceiver type specifies the channel type or types that it supports. The choice of
channel type affects transmission speed and distance as well as the network topology.
The Mini kit, LonMaker tool, and LonScanner tool, and Neuron chips support all
standard channel types, but not all Neuron chips support all transceiver and channel
types. Smart Transceivers combine the transceiver and Neuron chip core in the same
chip, and therefore support the channel types supported by the integrated transceiver.
Routers
Multiple channels can be connected using routers. Routers are used to manage network
message traffic, extend the physical size of a channel (both length and number of devices
attached), and connect channels that use different media (channel types) together.
Unlike other devices, routers are always attached to at least two channels.
The Mini kit does not install routers, but it can be used on networks with routers
installed by the LonMaker tool or other network management tool.