Integrations
What is BACnet?
BACnet (Building Automation and Control Network) is the dominant open protocol for building automation. Most modern BMS speak it natively.
What BACnet is. BACnet (Building Automation and Control Network) is an ANSI/ASHRAE standard, ISO 16484-5, for communication between building automation devices. It defines how controllers, sensors, and applications exchange object data, temperatures, setpoints, occupancy, alarm states, over IP, Ethernet, or older serial buses.
What it does. BACnet models a building as a set of standard object types, analog and binary values, schedules, trend logs, alarms, so devices from different vendors describe the same kind of point the same way. A controller doesn't need a proprietary driver for every brand on site; it reads and writes BACnet objects using one protocol.
BACnet vs Modbus, OPC UA and oBIX. BACnet is purpose-built for buildings, unlike the industrial-general Modbus. OPC UA carries a richer data model and stronger built-in security, which is why it's spreading from manufacturing into buildings. oBIX sits a level above all three, exposing a supervisor's picture of the building over plain HTTP. See the full comparison in our protocol guide for integrators.
| Protocol | What it's for | Transport model | Where you meet it |
|---|---|---|---|
| BACnet | Building automation, purpose-built | Standard objects over IP, Ethernet or MS/TP serial | Most modern BMS |
| Modbus | General industrial control, adopted by buildings | Register reads/writes over RTU serial or TCP | Meters, VFDs, older controllers |
| OPC UA | Secure industrial and building data exchange | Service-oriented, typed object model | Modern manufacturing, upgraded BMS |
| oBIX | Reading a supervisor's data as a web service | XML over HTTP | Niagara stations and supervisors |
Standards context. BACnet is maintained by ASHRAE's SSPC 135 committee and published internationally as ISO 16484-5. It has been extended over three decades, most BMS platforms sold today, from Siemens Desigo to Schneider EcoStruxure to Honeywell Niagara-based systems, support it as a native or add-on protocol.
How FrostLogic Explore connects. FrostLogic Explore reads BACnet, BACnet/IP and BACnet MS/TP via a gateway, natively. Write access starts off; we subscribe to point updates. You grant writes one scope at a time.
Before you ask
BACnet, the questions that come up.
Building Automation and Control Network. It's a communication standard, not a brand or a single vendor's product.
BACnet is purpose-built for buildings, with object types for things like schedules and alarms baked in. Modbus is older and simpler, just register values, built for general industrial control, and lacks that building-specific context. OPC UA carries a richer data model and stronger built-in security, and is increasingly used in both manufacturing and modernised buildings.
Both. BACnet/IP runs over standard Ethernet networks. BACnet MS/TP is the older serial variant, still common on legacy field buses, and is usually bridged to IP with a gateway.
Most of them. Siemens Desigo, Schneider EcoStruxure Building, Honeywell's Niagara-based systems and Johnson Controls Metasys all support BACnet natively or through an add-on card.
Yes, once you turn it on. Write access starts off. You grant it one scope at a time, and Explore proposes the change with its reasoning before anything moves. You choose whether that proposal waits for approval or runs automatically inside the scope you set.
Only for BACnet MS/TP serial devices. BACnet/IP points are read directly over the network. Older serial-only sites need a cheap IP gateway, which most integrators already stock.
BACnet/SC is the secure data-link layer for BACnet on IP networks. Traffic is encrypted with TLS, devices authenticate with certificates, and the transport rides WebSockets (usually over port 443) instead of the older plaintext BACnet/IP UDP model. The BACnet objects stay the same; only the wire changes. Sites that still run BACnet/IP or MS/TP keep those segments and bridge them with a BACnet router that speaks both SC and IP.
UDP 47808 (hex 0xBAC0) is the IANA-registered default port for BACnet/IP. Most controllers listen there out of the box. Some vendors use 47809 or 47810 to segment traffic, so confirm the port when you commission. BACnet/SC does not use this UDP port; it uses TLS WebSockets, commonly on 443.
A BACnet gateway (or protocol converter) translates between BACnet and another protocol so one supervisor or analytics layer can see both worlds. The usual case is Modbus meters or VFDs sitting next to a BACnet BMS: the gateway maps Modbus registers to BACnet objects, or the other way around. That is different from bridging BACnet MS/TP to BACnet/IP, which stays inside one protocol family. For the full protocol comparison and when conversion is worth it, see our BACnet vs Modbus vs OPC UA guide. For the Modbus side of the bridge, see What is Modbus?.
Related terms
Keep reading
See it in product
FrostLogic Explore
This is the engine that ships sensor intelligence as a product. Anomaly detection across six methods, forecasting with explicit confidence bounds, continuous compliance, what-if simulation, and Automation (permissioned BMS write-back) — all grounded in your own telemetry, all explainable, all auditable.
See FrostLogic Explore in action