Post Date: January 22, 2016 Topic: Controls Author: Gary Arlet
It seems that over the past few years, more so recently, you hear the term “BACnet™” being thrown around. So I thought this might be a good time to provide a high level flyover of what BACnet™ actually is. Building Automation Systems all use some type of “Communication Protocol”, or language to communicate. In years past, each manufacturer had their own “Proprietary” or private protocol. This meant that only that manufacturers devices could talk to each other. This was great for the manufacturer as once they got their systems into a facility, essentially, they locked themselves in since no other control system could communicate with them. Good for them, bad for the building owner.  

Then in the early 1980’s, members of ASHRAE started to develop a “common” language that would enable all manufacturers to communicate and share information, this later became known as BACnet™. (Building Automation Control Network) Recently, BACnet™ has become the standard communication protocol for building automation systems. There are others, such as LONWorks™ and MODbus™. Modbus is still used somewhat, more so in process type of applications. LON was probably the most widely used until recently when BACnet™ took over. The primary difference is, LON is “Pay to Play” This means every LON device has to have what is called an Echelon™ chip. This chip allows the device to communicate with other similar devices. There is a cost associated with each of these chips whereas with BACnet™, there is not. This has probably been one of the biggest contributors to the rise of BACnet™ and demise of LON’s popularity.  

One big misconception is that you can just plug BACnet™ devices together and they magically communicate. Well, it’s not quite that simple, however, generally any BACnet™ device can be made to communicate with other BACnet™ devices thus eliminating the lock manufacturers had on facilities. It is also possible for LON™ devices to communicate with BACnet™ devices, but the process is more difficult than communicating between like protocols.  

As we move forward, interoperability, or, the ability for different devices to work and operate together will become more and more common place. This will allow building owners/managers to access systems such as Fire Alarm, H.V.A.C, Lighting, and more easily and view information seamlessly.  

And now, you know the rest of the story.