Overview

LONWORKS is a networking platform 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.

Technology

The Neuron chip
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.

The LonTalk 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 Technology.

What about interoperability/compatibility - LonMark
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.




LONWORKS