LonWorks
Lesson 6.3
What LON Is
LonWorks, developed by Echelon Corporation and released in 1991, was one of the first peer-to-peer control networks designed for building automation. LON devices can talk directly to each other without a central controller.
At the heart of every LON device is a Neuron chip with a unique 48-bit Neuron ID burned in at the factory.
Physical layer: TP/FT-10: Twisted Pair, Free Topology, 10 Kbps. Unlike RS-485 which requires a strict daisy-chain, TP/FT-10 supports free topology.
LON was heavily adopted between 1995 and 2010. Many buildings are still running their original LON networks.
The Binding Model
LON devices communicate through bindings: associations between an output on one device and an input on another. Every LON device has Network Variables: nvo (outputs) and nvi (inputs).
Standard Network Variable Types (SNVTs): Data formats that all LonWorks devices use for common values. SNVT_temp is a temperature in Celsius. SNVT_switch is an on/off state.
Bindings are configuration, not wiring. When a device fails and you replace it, the replacement must be bound into the network before it works.
Commissioning LON Devices
- Find the Neuron ID: Every device has an ID sticker on the board.
- Commission the device: Send its Neuron ID to the network and assign a logical address and domain.
- Create or restore bindings: Connect network variables between devices.
- Test communication: Verify data flows correctly.
LON in Existing Buildings
LON is not being deployed in new construction at scale anymore. But there are millions of square feet of existing commercial space running LON right now.
The golden rule: Do not replace a LON device without the network database. Without it, the replacement device cannot be commissioned.
# OT/IT NETWORKS