LonWorks Network Components and Architecture

Components of a LonWorks Network

Node

Nodes are the intelligent devices on the network, containing a Neuron Chip, a transceiver, and other components. They communicate using the common EIA-709.1 LonTalk protocol.

• Must be checked and certified by LonMark to ensure interoperability.
• A network can support up to 127 nodes in a subnet and 32,385 nodes within a domain.

Neuron Chip

A microcontroller (chip) that implements the complete LonTalk communication protocol.

Neuron ID

A unique 48-bit address permanently assigned to each Neuron Chip within a node.

Transceiver

The interface responsible for adapting the signals from the Neuron Chip to the voltage levels required for the physical transmission medium.

Common Transceiver Types

• FTT-10A: Maximum 64 transceivers per segment.
• TP/XF-1250: Maximum 128 transceivers per segment.
• LPT-10: Maximum 128 transceivers per segment.

Channel

The physical communication medium. It supports up to 128 nodes through its transmission components.

Router

A device used to connect two channels. It contains two transceivers and occupies two node addresses. Routers reduce network traffic by filtering LonTalk messages based on their destination.

• Configured using a LonWorks network management tool.
• Can have up to 127 routers per port.
• Often includes a ferrite core to avoid interference.

Repeater

A device that connects two segments of the same channel, amplifying the signal in both directions.

• Forwards all messages regardless of destination (transparent operation).
• Requires the same physical media on both sides.
• Requires no configuration.
• Occupies two node addresses on the network.

Segment

A section of a channel. A channel can be divided into multiple segments using repeaters, with up to 64 nodes typically allowed per segment.

Terminations

Used to prevent signal echoes and interference on the network. Two types exist, often color-coded (e.g., green/red).

Logical Address

The address assigned to a node when it is commissioned and added to the LonWorks network.

Domain

A logical collection of nodes that belong to one or more channels. Communication between nodes can only occur if they are in the same domain.

Subnet

A logical partition of a domain. A domain can have up to 255 subnets.

LonWorks Network Architecture Summary

In the LonWorks architecture, the fundamental unit of communication is the node. The communication protocol is managed by the Neuron Chip within the node. Each node connects to the physical cable (the channel) via a transceiver. Channels can be extended into segments using repeaters, and multiple channels can be connected together using routers.