LonWorks (Local Operating Network) is a peer-to-peer networking protocol widely used in building automation, particularly in older commercial and institutional facilities.
LonWorks is a complete networking platform that includes:
| Component | Description |
|---|---|
| Protocol | LonTalk communication protocol |
| Neuron Chip | Embedded processor with protocol stack |
| Transceivers | Physical layer interfaces |
| Network Management | Tools for commissioning and maintenance |
| Feature | Description |
|---|---|
| Topology | Peer-to-peer (any device can talk to any) |
| Media | Twisted pair, power line, IP, fiber |
| Addressing | Neuron ID (unique 48-bit) + logical address |
| Data Model | Standard Network Variable Types (SNVTs) |
Free Topology (FT-10):
Twisted Pair (TP/XF-1250):
Network variables are the data points that devices share on the network:
| Property | Description |
|---|---|
| Name | Identifier (e.g., nviSpaceTemp) |
| Direction | Input (nvi) or Output (nvo) |
| Type | SNVT (standardized) or UNVT (proprietary) |
| Binding | Connection to other device NVs |
ASHRAE/ANSI defines standard types:
| SNVT | Type | Description |
|---|---|---|
| SNVT_temp_p | Temperature | °C × 100 (0.01°C resolution) |
| SNVT_lev_percent | Level | 0-100% (0.5% resolution) |
| SNVT_switch | Binary | On/off with value and state |
| SNVT_hvac_mode | HVAC Mode | Off, Heat, Cool, Auto, etc. |
| SNVT_occupancy | Occupancy | Occupied, Unoccupied, Bypass, Standby |
Reference: ANSI/CEA-709.1 (LonWorks Protocol Standard)
Devices communicate by binding output NVs to input NVs:
| Equipment | Manufacturer Examples |
|---|---|
| VAV Controllers | TAC, Honeywell Excel |
| Unitary Controllers | Carrier Comfort Network |
| Rooftop Units | Trane Tracer |
| Lighting Controls | Lutron, Leviton |
| Meters | Continental Controls |
Gateway approach:
Dual-protocol devices:
Niagara provides LonWorks integration via:
Primary commissioning tool:
| Tool | Purpose |
|---|---|
| NodeUtil | Basic device configuration |
| LonScanner | Network traffic analysis |
| Echelon i.LON | IP integration and management |
| State | Description |
|---|---|
| Unconfigured | New device, no network assignment |
| Configured | Assigned to subnet/node |
| Hard-offline | Intentionally disabled |
| Soft-offline | Communication lost |
Physical button on device for:
| Problem | Possible Cause |
|---|---|
| Device offline | Wiring, power, address conflict |
| No communication | Binding missing, routing issue |
| Incorrect values | SNVT mismatch, scaling issue |
| Slow response | Network congestion, wink storms |
| Factor | Consideration |
|---|---|
| Vendor support | Declining LonWorks focus |
| Integration | BACnet/IP more common |
| Tools | LonMaker licensing complexity |
| Skills | Fewer techs trained on LON |