Interview - September 2001
[Home Page]

[an error occurred while processing this directive]
(Click Message to Learn More)


Ken Sinclair and John James

John James is Vice President of the Products Group at Cimetrics Inc. His background includes over 32 years in the building automation and controls industry, with wide experience in both line and staff positions. He is based in Boston and can be reached at  or via the website

TCP/IP Protocol - The Real Contender? or Back To BACnet?

[an error occurred while processing this directive]Sinclair - What's wrong with the statement "Today's BAS standards will go the way of the Betamax and Quadraphonic sound. They'll simply be overrun by the revolution in technology that's taking place today"?

James: There are two different and distinct elements here that should be treated separately. They are the User Interface and the Control Network.

Using web technology for the User Interface is a great idea. Anyone with a PC and web browser can get BAS information.

However, the Control Network needs to have messages sent back and forth between control devices, and for those messages to be understood, regardless of the device supplier. BACnet objects and LonMark profiles are standard "languages" that permit this to occur. Most industries are struggling to develop standard "data definitions" for interoperability. Our industry leads in this area-BACnet objects and LonMark profiles allow devices from multiple manufacturers to communicate meaningfully with each other. In the specific case of BACnet, the standard is extensible, exemplified by the new BACnet objects and services for the Life Safety industry.

Sinclair - What's wrong with the statement "TCP/IP will replace BAS standards like BACnet and LonWorks"?

James: This is an "apples & oranges" comparison. BACnet objects and LonMark profiles are examples of Application-Layer standards and TCP/IP is a Transport, or Data-Link Layer standard. TCP/IP is a part of BACnet; BACnet/IP allows BACnet messages to be transported across TCP/IP networks without special routers or switches.

Sinclair - What about new standards such as XML?

James: XML is a method to represent information. Today, BACnet uses a binary representation, which is efficient but complicated. In the future XML could be used to represent BACnet objects when the infrastructure becomes cost-efficient.

Sinclair - How can BACnet help integrate video/security into total building automation integration packages?

James: The existing BACnet objects and services could be used for the control elements; e.g., pan, tilt, zoom, switching, etc. They could also be used to monitor and respond to alarms and events. Video signals would probably continue to be on a separate network, however. If the Security industry wanted to sponsor an initiative to create BACnet objects or services to better fit their requirements I'm sure the BACnet Committee would be receptive, similar to that which occurred for the Life Safety industry.

Sinclair - Do you have any concerns about convergence and total IT integration?

James: Other than the obvious security issues that would need to be addressed, I would be concerned about reliability. Other than 24/7 operations, such as data centers, IT networks aren't as reliable as is needed for BAS networks. All sorts of IT operations such as adding hubs and switches require that at least a portion of the network is taken down. Sometimes even adding a user workstation causes an interruption. Procedures would need to be put into place to minimize such disruptions.

The issue of BAS traffic is not generally a problem. The BAS manufacturers do a pretty good job minimizing control message traffic. However, if a top-level user issued a network broadcast that required all controllers to respond the entire network could be taken down. Procedures and/or safeguards would need to be implemented to preclude such actions.

[an error occurred while processing this directive]
[Click Banner To Learn More]

[Home Page]  [The Automator]  [About]  [Subscribe ]  [Contact Us]


Want Ads

Our Sponsors