Echelon NodeBuilder FX - Manual (Page 26)

12 Introduction
The U10 USB Network Interface connects directly to TP/FT-10 Free Topology Twisted Pair (ISO/IEC
14908-2) L
ON W ORKS channels through a high-quality removable connector. The U20 USB Network
Interface connects to PL-20 C-Band Power Line (ISO/IEC 14908-3) L ON W ORKS channels through an
included power supply with integrated coupler. The U20 USB Network Interface can also be
connected directly to 10.8-18VDC power systems (such as those in automobiles, trucks and buses)
without a coupling circuit, or to virtually any powered line through a customer-supplied coupler/power
supply.
The drivers for U10 and U20 USB network interfaces are automatically installed on your computer
when you install the LonMaker Integration Tool CD.
The USB Network Interfaces can be used with virtually any computer-based L ON W ORKS application,
including all LNS and OpenLDV ™ based applications such as the NodeBuilder Development tool,
LonMaker tool, and LonScanner Protocol Analyzer.
For more information on installing and using the U10 and U20 USB network interfaces, see the
LonWorks USB Network Interface User’s Guide.
Introduction to NodeBuilder Device Development and
L
ON
W
ORKS
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 communications channels.
Network devices are sometimes called nodes.
Devices may be Neuron hosted or host-based. Neuron hosted devices run a compiled Neuron C
application on a Neuron Chip or Smart Transceiver. You can use the NodeBuilder tool to develop,
test, and debug Neuron C applications for Neuron hosted devices.
Host-based devices run applications on a processor other than a Neuron Chip or Smart Transceiver.
Host-based devices may run applications written in any language available to the processor. A
host-based device may use a Neuron Chip or Smart Transceiver as a communications processor, or it
may handle both application processing and communications processing on the host processor. The
NodeBuilder tool 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
® 2.1 Developer’s
Kit or the FTXL ™ Developer’s Kit, 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 component called 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 LonTalk
protocol 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