What LonWorks Is
LonWorks is a control-network protocol family (ISO/IEC 14908) used heavily in legacy building automation deployments. It is most often encountered when integrating existing site controllers into newer BACnet or Modbus supervisory systems.
Core Concepts
| Concept | Description |
|---|---|
| SNVT | Standard Network Variable Type definition for point data types and units |
| XIF | External Interface File listing device network variables and attributes |
| Network Variable | Typed publish/subscribe data point used instead of register maps |
| Neuron ID | Unique device hardware identifier required for commissioning |
Integration Prerequisites
- Obtain the XIF file for each LonWorks device profile.
- Collect all Neuron IDs before gateway configuration starts.
- Confirm physical layer and channel details (FT-10, channel topology).
- Confirm unit conversion requirements (many SNVTs are metric-native).
[!WARNING] Do not start a LonWorks integration build without XIF files and Neuron IDs. Missing either input blocks mapping and commissioning.
Common Problems
- Missing XIF files from site documentation.
- Missing or mismatched Neuron IDs.
- Unit conversion issues (metric source data into imperial BMS points).
- Incorrect assumptions that LonWorks uses Modbus-style register addressing.