February 2009 |
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Building Automation Wishes for a New Year As with technology in general each advance seems to reveal the need for more advances to achieve that elusive state of perfection.
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Paul Ehrlich & Ira Goldschmidt |
With another new year upon us we find ourselves reflecting on the past year’s efforts and what might have made them easier or more successful. As usual this focus centers on the use of open communications protocols in our industry. Fortunately open protocols are clearly a success and are here to stay – the near universal support of BACnet (and LonTalk/LonMark to a lesser degree) by the BAS industry is a clear sign of this success. However, as with technology in general each advance seems to reveal the need for more advances to achieve that elusive state of perfection. What are they?:
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Interoperability for Operator Interfaces – As BACnet continue to build on its domination of the so-called building controller level of the market the need for interoperability at the next BAS component up the hierarchy continues to be missing. To-date there still is no BTL listing for Operator Interface functionality due to the lack of sufficient protocol support for these products in the original standard. Fortunately the BACnet committee has been working diligently to correct this matter for several for several years - the addendum covering this issue completed its 2nd public review in October 2008.
Adaptation of BACnet to Internet Protocols – BAS communications with many enterprise-level applications (i.e., Utility real time pricing and Microsoft server technologies to name just two) requires that BACnet become better adapted to Internet protocols and not the other way around. As an attempt to make this happen BACnet added support for Web Services to the standard 2006 (called “BACnet/WS”). Unfortunately this has not provided BACnet with what it truly needs to provide enterprise-level interoperability. Instead a second addendum called “XML Data Formats” completed its 1st public review in October 2008.
More Use of Open Protocols for Building Equipment/Systems – As mentioned above, BAS manufacturers have demonstrated a near-universal support of open protocols. Unfortunately, the same cannot be said for the most of the manufacturers of other computerized building equipment controls and systems. These other products include the myriad of manufacturer-provided HVAC equipment controls (i.e., chillers, RTU’s, etc.); fire alarm, lighting, and access control systems; and electrical systems (i.e., UPS’s, PDU’s etc.). On the surface the support appears to be there – most of these products generally provide a BACnet, LonTalk, or Modbus communications option. However, when you look a little closer much of this support does not provide enough capability for the needs of an intelligent building. In particular gateways are generally used which typically only allow for simple reading and writing of data. Unfortunately intelligent interoperability requires the support of more complex data structures, like schedules and trend logs, and support of services like change of value reporting (i.e., data is only sent when it has changed, thereby freeing up the communication systems from the constant polling of data).
[an error occurred while processing this directive] Better Support from Manufacturers and Representatives – Not only is the application of open communication technology for the above equipment/systems lacking, but the customer support for the technology aspect is also lacking. The documentation that describes the communications capabilities is usually terse, incomplete or written only for “in-house” use. Further, representatives do not generally have the knowledge to provide support concerning their product’s communications capabilities or the interpretation of the documentation. We are constantly disappointed when we ask a representative for technical details of a product’s communications support (i.e., a “PICS”) along with a list of data that can be communicated - it’s amazing how many times we get the answer “we support BACnet and all data is available”!
Standardization of Wireless Communications – Wireless devices are becoming more commonplace in our industry. However, there is still no protocol standardization concerning these products. This shortcoming is really needed for the widespread use of wirelessly-communicating zone controllers (i.e., for VAV boxes), an application which has the potential of significantly reducing installation costs. While there is an effort on the part of the BACnet committee to incorporate a wireless technology into the standard (an addendum addressing this issue completed its 1st public review in May 2008), it remains unclear to us where this effort is heading and if it will be completed in 2009.
Let’s hope the new year yields success or at least improvements for all of the above!
About the Authors
Paul and Ira first worked together on a series of ASHRAE projects including the BACnet committee and Guideline 13 – Specifying DDC Controls. The formation of Building Intelligence Group provided them the ability to work together professionally providing assistance to owners with the planning, design and development of Intelligent Building Systems. Building Intelligence Group provides services for clients worldwide including leading Universities, Corporations, and Developers. More information can be found at www.buildingintelligencegroup.com We also invite you to contact us directly at Paul@buildingintelligencegroup.com or ira@buildingintelligencegroup.com
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