For the new investors, some background on Lonworks from Echelon:
LONWORKS Networks Frequently Asked Questions
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General LONWORKS General
Dictionary
What is a control network? LonSupport Preview
What are LONWORKS Networks? Echelon Background
What are LONWORKS Networks for? Contact Echelon
Who supplies the basic technology? Echelon Home
Who uses it?
Shouldn't I wait for a standard?
What is a Neuron and why use it?
How fast can the protocol be run?
The Protocol
How extensive is the communications protocol?
Is It Reliable?
Is performance predictable?
What about network management?
Is it secure?
What does the programming model look like?
Interoperability
What is interoperability and what are its
benefits?
How is product interoperability assured using
LONWORKS networks?
What is a control network?
A control network is a group of things (nodes - each with one or more
sensors or actuators, plus localized computational capability), that
communicate (over one or more media, using a standard protocol) to
implement a sense and control, sense, or monitoring application.
A control network is more common than you think. For example, your car may
have several control networks in, e.g., the seat belt warning system, the
ABS braking system or the engine management system. A control network may
have 3 nodes, or 300, or 30,000, or more and can range in complexity from a
few "smart" light switches on a timer to a jet passenger airplane (both of
which are examples of existing LONWORKS networks). It may be a simple alarm
controlled by a remote occupancy sensor, or a city's traffic management
system, monitoring and controlling signal lights, traffic flow, the actions
of emergency vehicles, power distribution, etc.
To many people, control networks are most easily understood as smart houses
or home automation. However, most control systems in use today are in
commercial buildings and factories doing such things as sorting books or
building cars or controlling an elevator. LONWORKS networks are used for
all of these and more. Communication among the nodes may be peer-to-peer
(distributed control) or master-slave (centralized control); in either
case, intelligence in the nodes (computational capability) permits the
distribution of processing loads (sensors can be intelligent, for example,
performing local data analysis, conversion, & normalization, and reporting
only significant changes in their environment). If the control functions
are also distributed, both system performance and reliability can be
dramatically enhanced.
As Robert Metcalfe, the founder of 3Com Corporation, once said, "The power
of a network is proportional to the number of nodes on it." Given that
there are vastly more nodes perfoming control than data functions (LANs),
it's clear that the most powerful networks in existence are control
networks.
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What are LONWORKS networks?
LONWORKS is a networking technology created by Echelon. LONWORKS networks
really describe a complete solution to the problem of control systems. Like
the computer industry, the control industry was, and in many cases is,
creating centralized control solutions based on point-to-point wiring and
hierarchical logic systems. This meant that you had a "master" controller,
like a computer or programmable logic controller, physically wired to
individual control, monitoring and sensing points, or "slaves." The net
result worked, but was expensive and difficult to maintain, expand, and
service. It was also very expensive to install.
LONWORKS networks started out with some very simple notions - control
systems are fundamentally the same regardless of application; a networked
control system is significantly more powerful, flexible, and scaleable than
a non-networked control system; and businesses can save and make more money
building control networks over the long term than they can with
non-networked control systems.
LONWORKS technology provides a solution to the many problems of designing,
building, installing, and maintaining control networks: networks that can
range in size from two to 32,000 devices and can be used in everything from
supermarkets to petroleum plants, from aircraft to railway cars, from
fusion lasers to slot machines, from single family homes to skyscrapers. In
almost every industry today, there is a trend away from proprietary control
schemes and centralized systems. Manufacturers are using open,
off-the-shelf chips, operating systems, and parts to build products that
feature improved reliability, flexibility, system cost, and performance.
LONWORKS technology is accelerating the trend away from proprietary control
schemes and centralized systems by providing interoperability, robust
technology, faster development, and scale economies.
Echelon manufacturers over 80 products to help developers, system
integrators, and end-users implement LONWORKS networks. These products
provide a complete LONWORKS solution including development tools, network
management software, power line and twisted pair transceivers and control
modules, network interfaces, technical support and training.
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What are LONWORKS Networks used for ?
In theory, all control network applications, across all industries. In
practice, present-day silicon implementations restrict its use to networks
requiring a transmission rate of no more than 1.25 Mbits/s, and a (true,
end-to-end) response time of no less than 7-13 ms across the network
(response times within individual nodes are much faster).
Applications for which LONWORKS networks technology are used today include
appliance control, asset tracking, automated supermarket pricing, automated
work environments, avionics instrument integration, circuit board
diagnostics, consumer electronic controls, discrete and process control,
electronic locks, elevator control, energy management, environmental
monitoring, fire protection, HVAC control, highway toll collection,
identification systems, intelligent industrial I/O, irrigation management,
lighting control, liquor dispensing, livestock management, medical
instrumentation, office machine automation, patient monitoring, power
supply management, research experiment monitoring, restaurant automation,
security systems, slot machines, traffic lights, utility meter reading,
vehicle wiring systems, vending machines, whole house automation, wire
harness replacement, and many more...
Check out our LONWORKS Networks at Work section to find out in detail.
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Who supplies the basic technology?
The principal suppliers of LONWORKS networks technology are:
Echelon Corporation - development tools, transceivers, network management
tools, support and training (creator of the technology, and provider of
transceivers, connectivity products, development tools, and training),
Motorola and Toshiba - Neuron chips (competing world-wide suppliers of
variously packaged versions of the Neuron chip).
Additionally there are over 3000 LONWORKS developers world-wide supplying
everything from transceivers to network management tools, to interfaces, to
end-user products and systems. To find out more see Echelon's Resource
Directory of LONWORKS control network products and services, listing many
of these suppliers.
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Who uses it?
Over 3000 companies use LONWORKS networks today, and their numbers are
growing rapidly. These include Companies that have made public statements
about their usage include ABB Network Partner, ABB-Stromberg Power,
Acromag, Action Instruments, Advance Transformer, AEG, Ahlstrom Elari,
Allen-Bradley, American Sports Timing, AMP, AT&T, Bally Systems, Barrington
Systems, Bell Northern Research, BTE, British Petroleum, British Telecom,
Brooks Instrument, Card Monroe, Carrier Corp., Controlli S.P.A., Danfoss
Automatic Controls, Detroit Edison, EG&G Idaho, EIL Instruments, Fabrisys
(Alcatel Cable), Ferag AG, Goldstar Industrial Systems, Helvar,
Hewlett-Packard, Honeywell, Hubbell, ITT Barton, Jet Propulsion Laboratory,
Johnson Controls, Keene Widelite, Kollmorgen, Legrand, Lakewood
Instruments, Landis & Gyr Powers, Leax, Legrand, Leviton Manufacturing,
Lithonia Lighting, Litton Poly-Scientific, McQuay International, Metra
Corporation [Image], MK Electric, Molex, Montgomery Elevator, NASA, Nippon
Steel, Olivetti, Orr Safety, Pensar Corporation, Philips Lighting, Potter
Electric Signal, Raychem, Scitronix Corporation, Shlumberger Industries,
Sea Hornet Marine, Sentrol, Siebe Environmental Controls, Solus Technology,
Square D, Staefa Control Systems, Toshiba Lighting, Trans-Lite, Trend
Control Systems, Tru-Measur, Unisys, Weidmuller, Woodward Governor, and
many more...
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Shouldn't I wait for a standard?
LONWORKS networks have become a de facto standard by virtue of their
acceptance in many segments of the controls market. Manufacturers,
end-users, integrators, and suppliers are seeing increasing demand for
control solutions that have the capabilities that LONWORKS networks
deliver. As a result, thousands of LONWORKS solutions have been implemented
world-wide.
Standards setting and standards recommending bodies have reached the same
level of acceptance. Now, in addition to the weight of common acceptance,
LONWORKS networks have been included in several standards or standards
efforts including:
* The protocol has been included in EIA-709.1, the Electronic Industries
Alliance (EIA) Control Network Protocol Specification. It is available
for purchase from Global Engineering Documents.
* The protocol is part of the American Society of Heating,
Refrigeration, and Air-Conditioning Engineers' BACnet control standard
for buildings. This is now known as ANSI/ASHRAE 135.
* LONWORKS is also the standard protocol of the International Federation
of Forecourt Standards (all European gasoline stations).
* The American Association of Railroads has chosen LONWORKS as the
standard for pneumatic braking systems.
* SEMI (Semiconductor Equipment Materials International) specifies
LONWORKS as a sensor bus for connecting simple as well as complex
sensors, actuators and instrumentation within equipment and between
equipment in E-56.6.
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What is a Neuron? .. Why use it?
The Neuron is actually 3 8-bit inline processors in one. Two are optimized
for executing the protocol, leaving the third for the node's application.
It is therefore both a network communications processor and an application
processor. Up until recently, all devices on a LONWORKS network required a
Neuron.
Why use it?
Having two processors dedicated to network tasks and one dedicated to
application tasks ensures that the complexity of the application does not
negatively impact network responsiveness and vice versa. Additionally,
packaging both functions onto one chip save design and production costs.
Use of the Neuron chip guarantees a controlled hardware execution
environment for the protocol. To ensure sufficient processing power, the
protocol is implemented with a mixture of hardware and firmware.
The creation of a custom chip also allows the inclusion of additional
functionality to facilitate control node design. The Neuron chip, for
example, incorporates watchdog timers, on-board diagnostics, 35 device
controller types, a distributed real-time operating system, run-time
libraries, three types of memory, and even a 48-bit software-accessible
serial number (which, guaranteed by the chip's manufacturers to be unique,
provides an always-available installation address for any Neuron chip-based
node).
Designed for a broad range of industries and applications, and
consequently manufactured in volume by two of the world's largest
semiconductor manufacturers, the Neuron chip offers a lower-cost
instantiation of the LonTalk protocol than could be achieved in custom
implementations.
The net result is that the Neuron Chip is the best and most economical
LONWORKS processor for anyone requiring 8-bit processing power.
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How fast can the protocol be run?
At one time the speed was limited to 10MHz. However, a new 20MHz
implementation has been completed opening the way for the highest
performance Neuron based LONWORKS networks ever.
Further, as the developers find more uses for the protocol, processing
horsepower can become an issue. Echelon has addressed this by opening up
the LonTalk protocol to allow any company to port it to the processor of
their choice. This means that applications requiring 16 or 32 bit
processing power, can now host the protocol in native mode.
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How extensive is the communications protocol?
Protocols today are generally designed to follow the ISO standard "Open
Systems Interconnection Reference Model," which encompasses a full set of
protocol features, and classifies them according to seven functional
categories (referred to as "layers"). Thus the "seven layer OSI model".
The LonTalk protocol implements all seven layers of the OSI model, and does
so using a mixture of hardware and firmware on a silicon chip, thus
precluding any possibility of accidental (or intentional!) modification.
Features include media access, transaction acknowledgement, and
peer-to-peer communication, and more advanced services such as sender
authentication, priority transmissions, duplicate message detection,
collision avoidance, automatic retries, mixed data rates, client-server
support, foreign frame transmission, data type standardization and
identification, unicast/multicast/broadcast addressing, mixed media
support, and error detection & recovery. For an overview of the LonTalk
design, and the benefits of fully functional protocols, refer to "LonTalk
Protocol Rationale", available from Echelon Corporation.
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Is It Reliable? What provisions for reliability are incorporated?
The LonTalk protocol offers two principal reliability techniques. Reliable
delivery is assured by true end-to-end acknowledgements, made possible by a
full OSI based protocol and the fact that it is encapsulated in silicon
(most protocols can only guarantee that a packet was successfully
transmitted, not that it was actually received by the application). Data
integrity is guaranteed by the fact that *all* packet transmissions
incorporate, not parity, not a checksum, but a full 16-bit error
polynomial.
Additionally, transceivers for difficult media (i.e., low bandwidth, with
high noise and attenuation) additionally incorporate forward error
correction, able to detect and correct single bit errors without
retransmission.
If you're using a Neuron Chip, you also get The Neuron chip contains
self-test circuitry, three watchdog timers, and a variety of diagnostic
features such as a continuous EEPROM memory corruption check.
AT&T chose LONWORKS networks technology for the implementation of their
most critical business function - switching network offices. Of this
application, Michael J. Wheeler (Technical Manager, Office Infrastructure
Development) said, "... no other viable option open to AT&T... would have
provided the efficiency or performance we found in your (LONWORKS)
technology. Moreover, the overall system reliability is everything Echelon
promised, and more."
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Is performance predictable?
An integral part of the protocol used in LONWORKS networks is its unique
media access technique, termed "predictive p-persistent CSMA, with optional
priority & collision detection." It provides linear response to offered
traffic load, predictable response time for heavily loaded networks, and
consistent performance independent of network size.
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What about network management?
LONWORKS networks incorporate a full set of network management
(installation, configuration, & maintenance) facilities. All products can
be installed at manufacturing time, and - unless prohibited by
authentication - by using third-party installation tools; they can also be
designed for self installation. Network management functions include node
address assignment, multicast address group specification, router & bridge
definition, network variable binding, communication service modification,
network traffic data monitoring/collection, node/network diagnostics,
application code/data downloading, etc.
If you use LNS, then you get the added benefit of being able to do many of
these things simultaneously using devices and tools tailored for the
operator or technician and the specific task.
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Is it secure? Can access control (security) be guaranteed?
All network operations (including network management) are performed using a
full "sender authentication" as a Layer 4 (of the OSI model) service (this
provides a guarantee of sender authenticity, which cannot be forged or
"hacked"). Every packet transmission can use sender authentication. The
bottom line is that you can invoke this facility. Thus, by a selective use
of authentication, security firewalls can be established where appropriate.
And because the protocol is embedded in silicon, authentication is
guaranteed to work throughout the network, regardless of individual product
implementation choices.
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What does the programming model look like?
Applications for LONWORKS networks are written in "Neuron C." This is
really just ANSI C, plus three extensions:
* A new statement type, the "when" statement, to introduce "events", and
define task execution order;
* 37 additional data types, 35 I/O objects and 2 timer objects, to
simplify and standardize device controller usage, and;
* Integral message-passing mechanisms for both explicit (physical,
logical, and destination-name addressing) and implicit (network
variable) message formats.
Neuron C uses a programming model based on events. In other words,
applications are typically triggered by events occurring elsewhere on the
network or at the particular node. Therefore, the network itself is event
driven. This means that LONWORKS networks have much lower traffic than
other types of networks, like your office LAN.
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What is interoperability and what are its benefits?
Echelon defines interoperable as the ability to integrate products from
multiple vendors into flexible, functional systems without the need to
develop custom hardware, software, or tools. By integrate, we don't just
mean see each other, we mean being able to do things like use only one room
occupancy sensor for the HVAC, lighting, and security systems in a
commercial building. We mean being able to have your assembly line react to
your building's fire system.
To help lead in the mission of delivering interoperable LONWORKS based
products to the control market, Echelon is a sponsor member of the LonMark
Interoperability Association.
Four Benefits of Interoperability
Interoperable products allow project engineers to specify best of
breed systems rather than be forced into using one vendor's
entire line of products.
Interoperable products increase the overall market for your
products by allowing you to compete for what would otherwise be
closed bids.
Interoperability decreases your own products costs among your
business' division by allowing your engineering teams to build to
a standard specification.
Interoperable systems allow building and plant managers to
monitor facility wide using standard tools, regardless of which
company made a particular sub-system.
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How is product interoperability assured?
For many users of control networks, this is the single most important
question. Interoperable products can expand your business, increase your
profit margins, save your customers money, and offer you increased vendor
choices when specifying systems. In short, it's good for everyone from
developers, to integrators to end-users. Integration without frustration -
the ability to integrate products from multiple sources without the need
for custom development - can be the driving force that leads to the search
for a control network technology.
LONWORKS networks approach interoperability in three main ways. Technology
offers a three-part solution to this challenge.
First, up until 1996, Echelon made the protocol available on the Neuron
Chip only. Since most every LONWORKS node available today has a Neuron in
it, they share a baseline level of interoperability. it encapsulates as
much as possible into standard silicon, to reduce the potential for
diverging interpretations. This serves two purposes. One, it provides to
every LONWORKS application utilizing Neurons a fundamental commonality at
the silicon level. Two, it provides over 3 million (and counting) devices
installed world-wide, and each can be thought of a an interoperability
reference for any ported processor (non-Neuron processors running the
LonTalk protocol). Echelon ensures, via license, that any port of the
protocol must interoperate with the Neuron chip.
Second, it incorporates standard types & objects (so products can agree on
the meaning of shared data), and an intrinsic control model (because
extrinsic control limits interoperability) into the programming model.
Third, an independent body, the LonMark Interoperability Association, has
been established to manage the evolution of both the interoperability model
and the certification of products that conform to the interoperability
standard.
There are presently over 150 members, from more than 15 countries,
including ABB Network Partners, Ahlstrom, Ameritech, Carrier, Detroit
Edison, Echelon, Honeywell, Hubbell, HP, IBM, Leviton, Microsoft, Molex,
Motorola, Philips, Olivetti, Raytheon, SIEBE, SILD, Square D, Staefa,
Toshiba, Weidmuller, and Yokogawa
The association establishes technical guidelines and promotes the LonMark
interoperability standard worldwide.
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