What are some of the advantages of using Internet protocols (TCP/IP) instead of BAS-specific protocols such as BACnet, LonWorks?
TCP/IP Internet Protocols are…
- well defined.
- widely accepted.
- free. No single company controls them.
Anyone can look up the standards and can choose from a long list of component manufacturers.
Internet protocols are continually improved and benefit from research and development from thousands of companies across hundreds of industries. The amount of money in R&D for the Internet and Internet-related technologies dwarfs that in the building automation industry.
Internet protocols allow building automation systems to cross industry boundaries and interface with a wide variety of other systems.
Internet protocols allow separate systems and groups of components to share the same set of wires. This reduces the overall cost of installing and maintaining several systems.
Internet technology is not limited to desktop computers. The term Internet Appliance is applied to embedded electronic devices that use standard Internet protocols. Internet appliances are small devices (like building automation system components) that have this type of Internet protocol capabilities built in them. There is a tremendous amount of research in this area. The vision is to have all of the electronic devices in the home and office communicating with each other and sharing information. Devices from different manufacturers will instantly connect and exchange meaningful data with each other.
BACnet
One of the advantages of BACnet was that BACnet was developed by what was supposed to be an unbiased committee. This is in direct contrast to standards like LonWorks® that are essentially dictated by a single corporation. In addition, BACnect covers the specific needs of the building automation industry.
One of the disadvantages of BACnet has been that cooperation among the players has been half-hearted. There have been many releases of BACnet products that were not 100% compliant. True interoperability between these products and compliant products could not be achieved. This left consumers somewhat disillusioned. To address this problem the BACnet Testing Laboratories® (BTL) was formed. But this was not launched until the year 2000—13 years after the conception of BACnet!
Another problem is that, in general, the technology behind BACnet is not comparable to the state-of-the-art networking technology found in other industries and standards. Part of this is due to the sluggish pace of the standards committee. To address this major shortcoming, BACnet/IP was quickly introduced after the initial release. The idea of BACnet/IP is to place BACnet packets over the Internet. But this was more of an afterthought than a primary design goal. And it only further muddied the already murky waters of BAS interoperability.
LonWorks
LonWorks® is a standard that was developed by the Echelon Corporation. From its’ conception, LonWorks® has revolved around the LonTalk® protocol and the company’s Neuron® chips. Unlike BACnet, LonWorks® was developed by and is primarily controlled by a single company. Until recently, any product that was LonWorks® compatible contained one of Echelon’s Neuron chips. This of course raises the question of whether or not LonWorks® is truly open. To have the entire standard placed at the mercy of a single company is not an ideal situation for many manufacturers.
One benefit of the single-company philosophy is controlled interoperability. By having Echelon enforce strict implementation of the LonTalk protocol, LonWorks® products achieve a higher degree of interoperability between multiple manufacturers than does BACnet. But this is at the cost of soul-source components and licenses.
Even though Echelon is the sole source for LonWorks, it has managed to get the LonWorks standard accepted as part of several other open standards. For example, LonWorks is an accepted part of the BACnet standard. But in practice, these two standards are rarely used together. Ira Goldscmidt [1] had the following to say about the inclusion of the LonTalk protocol into the BACnet standard:
“The issue of including LonTalk as a LAN technology within BACnet was passed prior to the third public review of the standard in 1995. The alternative appeared to be a deadlock and potential appeal of BACnet by Echelon, which led to an observer’s remark that some committee members held their noses while voting ‘yes.’”
References
[1] Ira Goldschmidt, “Development of BACnet”, Association of Energy Engineers “Strategic Planning for Energy and the Environment”, November 1998.
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