The Basics – What is BACnet?

BACnet is a popular building automation protocol used worldwide to enable communication between devices in commercial automation systems. Industrial automation has historically used other protocols such as OPC and Modbus. BACnet standardizes communication across vendors and simplifies the integration process.

The name BACnet stands for building automation and control network. It was created by the American Society of Heating, Refrigerating and Air-Conditioning Engineers by a committee of industry professionals to modernize communication for automation systems using an open protocol.

Open – To Intepretation

It’s a open standard, anyone can get a full copy of it if they are willing to pay for it. Closed standards are proprietary communication systems created by vendors for their own devices. Open systems allow multiple vendors to utilize a common communication backbone and automation front end. It’s also a very easy standard to comply with, as it requires very little of you. This can be a challenge for system integrators.

A device does not need to support much of the BACnet standard to be a compliant BACnet device. So long as it knows how to say hello to other devices, it’s a BACnet device. This flexibility presents a challenge for integrators, as vendors can implement as much or at little of the standard as they like. Sometimes a vendor won’t bother to put any useful metadata in the standard fields for points. You’ll see analogObject_1 through 500 with no way of determining what anything represents. Lazy BACnet might as well be Modbus.

When implemented well by the vendor, BACnet is damn near pleasurable to work with. It makes some hard things easy since it is designed for our industry. The old school controls guys are not fans of BACnet because larger systems get into the realm of computer networking.