Canadian Consulting Engineer

HVAC Controls Q & A

August 1, 2007
By Canadian Consulting Engineer

Q. What is the single biggest challenge on a building automation system (BAS) job today?

Q. What is the single biggest challenge on a building automation system (BAS) job today?

By far, it is commissioning. The problem is getting all the responsible parties (mechanical contractor, electrician, equipment manufacturer — and in some cases the consultant) orchestrated to perform end-to-end commissioning. Coordinating the parties to be on site to check the correct operation of all the equipment through all modes of operation in the summer, swing and winter season is almost impossible.

Commissioning agents help, but there needs to be more responsibility placed on the equipment manufacturers to stay on site to ensure their equipment is responding correctly to the BAS commands.

Q. What is an “open” system?

To Airon, an “open” system is one in which each component in the architecture is selected and assembled in a manner that would allow multiple vendors access to review, revise and expand the system, one that does not require the exclusive services of the product manufacturer or the installing contractor.

Q. Are the systems being installed today “open”?

We do not want to get into a debate on openness. From Airon’s perspective, if a manufacturer or contractor wants to manipulate the idea of system openness, they will.

Specifications do not drive the industry; products and marketing drive the industry. If a manufacturer or contractor has a marketing strategy that has historically relied on taking the end user hostage on future service and system expansions, then most likely they are going to propose a component architecture that will resemble this strategy.

But if a manufacturer or contractor has historically relied on building business by providing the end user with the best solution based on product quality and future flexibility, then most likely they are going to propose a component architecture that resembles that strategy.

Q. Can you provide an example?

Sure. An example would be a front-end software package that is marketed exclusively to a manufacturer’s branch outlets. Although the entire system may be installed using open technology, access to the front-end software is held exclusively by the branch organization.

Although the manufacturers and contractors trained and certified in the chosen open technology may make changes to the system components, the original installer guards the mapping of information to the front-end software. In such cases, the end user [building owner] would succumb to “hostage taking” marketing or pay the price to have the front-end software package replaced with a multi-vendor product.

Q. In a multi-vendor system, isn’t the owner at risk of having an inferior installation performed by unqualified contractors?

Absolutely. However, this danger can be easily avoided if the consultant does his or her homework in pre-qualifying experienced contractors with a track record of credibility.

Q. What open systems are available on the market today?

Most major manufacturers have an open system offering. By “open,” we are referring to the communication between controllers, equipment and the front end being performed using standard published protocols such as LonWorks, BACnet and Modbus.

Q. Which protocol is more prevalent in the market?

By far there are more Lon-certified products available than any other in the building automation field. Echelon Corporation developed the neuron chip in which the LonWorks communication technology resides and has mass-marketed the technology.

Q. What about BACnet?

The BACnet protocol was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHREA). BACnet is a set of compliance standards for network communication and component programming that can be specified as a minimum on a project.

Q. Based on your description it would seem that BACnet is truly open as it is based on compliance standards?

Yes. However, remember that from our perspective, it is products and marketing that drive the industry.

We have found that some manufacturers are restricting access to their BACnet BTL certified products to their branch channels or licensed territorial distributors. So by limiting access to the product and by adding a key proprietary component to their architecture, they are back to the “hostage taking” marketing strategy.

Echelon has mass-marketed their LonWorks technology and it is available virtually to any manufacturer. Furthermore, they have developed a standard compliance testing procedure that can be performed over the internet. Therefore, if you go back to our perception of “Open,” you can see why we do not want to debate the issue.

Q. What about Modbus?

Modbus is an industrial standard that some equipment manufacturers have adopted to share read/write data.

Q. In Airon’s opinion, which open protocol is better?

We have a lot of experience with LonWorks and are very comfortable working with a major manufacturer’s LonWorks products. We also like the fact that we can obtain hundreds of LonWorks products from many different suppliers. This really complements our integration capabilities.

That being said, we have also worked with BACnet products and found them very versatile as well.

Our Modbus experience has been mostly in the area of equipment integration.

We really do not have a preference. Our concern is the client and providing them with the best solution based on product quality and future flexibility.

Q. Where do you see the building controls industry going?

We see a building facility as a complex structure of systems. Traditionally, these systems have been installed independently with separate proprietary communication networks isolating each system from the other.

With modern technology, using open, published communication protocols, the systems can be installed on a common communication network. This saves money by eliminating multiple communication networks and provides for the instantaneous sharing of critical information between key building systems such as metering, HVAC, lighting, access control, CCTV and fire. Through common networking, the information can be efficiently managed using standard enterprise technology such as web services, e-mail, etc. The result will be lower costs for installation, facility management, and energy consumption.


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