• LONWORKS(Local Operation Networks) technology is an important new solution for control networks developed by Echelon? Corporation
• A control network is any group of devices working in a peer-to-peer fashion to monitor:
  – sensors
  – control actuators
  – communicate reliably
  – manage network operation
  – and provide complete access to network data
• In some ways, a LONWORKS control network resembles LAN
• It can control and link factory conveyor belts, product inventory, and distribution systems for optimum efficiency and flexibility
• Smart office buildings can turn lights on and off, open and lock doors, start and stop elevators, and connect all functions to a central security system
• Homeowners can program a vast array of products and conveniences, from sprinkler systems to VCRs, with a touch tone phone from any remote location
• LONWORKS technology is a solution for implementing distributed control networks
  – These networks consist of nodes that communicate with one another over a variety of communications media using LonTalk? protocol
• A common message-based communications protocol
• In a LONWORKS application, nodes sense, monitor, count, measure time, manage switches and relays, and respond to conditions reported by other smart nodes
• The technology of distributed nodes can reduce the amount of wire and number of junctions by one or more orders of magnitude
  – As a result, the network has simpler field installation, increased reliability, and decreased cost
• Since the communications protocol supports different transmission media, such as twisted pair, RF, and power line, the network is extremely flexible

LONWorks Applications

LONTalk Protocol

• It is a common message-based communications protocol
• The LonTalk protocol implements all seven layers of the OSI model
  – Using a mixture of hardware and firmware on a silicon chip
• thus precluding any possibility of accidental (or intentional!) modification
• The protocol can be run as fast as 20 MHz
• Features include:
  – Media Access
  – Transaction
  Acknowledgement
  – Peer-to-peer Communication
  – 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
  – Error Detection & Recovery

LONWorks Network Service (LNS) Architecture

• Services are provided using:
  – Network Service Server (NSS)
  – Network Service Interface (NSI)
• The NSS
  – Process standard network services
  – Maintains the network database
  – Enables and coordinates multiple points of access to its services and data
• The NSI
  – Provides the physical connection to the network
  – Manages transactions with the NSS and application servers
  – Provides transparent remote access to the NSS and application servers
• Each host is attached to the network using an NSI
  – The host can be any microcontroller, Microprocessor, or PC running
  any operation system