Open Systems: An Ongoing Quest
August 1, 2007
By Lee Norton, P.Eng.
These days, due to advances in computerization, a person working alone in his garage with a mixture of readily available controllers, valves and assorted equipment could provide a building automation ...
These days, due to advances in computerization, a person working alone in his garage with a mixture of readily available controllers, valves and assorted equipment could provide a building automation system (BAS) to satisfy any building’s need. These systems may not be user friendly, however, and repairing or expanding them can be a nightmare if the original installer is no longer available.
The systems from the main manufacturers are, of course, much easier to navigate and expand than those from the smaller contractors. As well, the manufacturers each offer training to educate their clients’ operators.
Yet the service provided by the major building control system manufacturers is a sore point with many clients. In the past, building owners often felt they were being exploited. As an example, 10 years ago, a manufacturer charged one of our clients $14,000 to relocate 14 temperature sensors. The manufacturer insisted that it had to do the work as the system was delicate and could cease working or crash if the proper procedure was not followed. Incidentally, half of the sensors were to be relocated closer to their source, so no rewiring or breaking of existing wiring was required on the sensors. Every consulting engineer remembers a case like this and it has led to some clients not trusting any control contractors.
We specify that the manufacturer must ensure all components on the installed system are kept available for a minimum of 10 years. By this means we hope to ensure the system has a long service life. Technology is moving so fast that some older controllers won’t speak to later ones, making it impossible to repair and extend the system without purchasing extensive upgrades. We also specify that update patches and licensing of the software will not have additional charges.
The LonMark vs. BACnet debate continues
Clients’ lack of trust for manufacturers had led to a demand for open systems. Clients want to be free from having to use the same contractor who installed the system to upgrade or repair them. This need has led to open protocols such as BACnet and LonWorks.
Both BACnet and LonWorks provide published data on their open protocol controllers in order to allow independent contractors to service the equipment.
Usually, however, the front end or user interface that reads, stores and calculates the information from the controllers is still proprietary to each manufacturer. There are exceptions, such as the Tridium system, but these are not yet in common use, which means the client has to find contractors familiar and willing to work with them.
Open systems have their own language and idiosyncrasies that the contractor must learn to deal with. Our research indicates the learning curve for LonWorks is more difficult than the one for BACnet.
We have also found that although LonWorks seems to have a lead in the number of controllers and installations, the manufacturers are more prone to presenting BACnet when an open protocol is asked for.
BACnet controllers can have problems as the testing for BACnet certification is not 100% foolproof. For example we have just worked through a problem case where the BACnet VAV controllers would bring the building automation system down on an irregular basis. After months of trial and error and fixes that didn’t fix, or only worked for a week before the system crashed again, we think we found the problem. The U.S.-based testing components used Fahrenheit and not Celsius for temperature measurement, but in Canadian government buildings — as this one was — Celsius is specified. The conversion from Fahrenheit to Celsius was done inside the controller and was the cause of the intermittent problem. Once discovered, this discrepancy seemed to be a really simple issue, but it caused an expensive delay in both time and money.
In our region of Canada one manufacturer has set up a contractor certification program. Certified contractors are allowed to purchase controllers and other equipment directly from the manufacturer at prices equal to the manufacturer’s local sales site. As a result, in the Toronto area a client using that manufacturer’s system has the ability to choose from half a dozen contractors. If there is a conflict between a contractor and the client, another contractor can be brought in. I understand that other manufacturers are following this example, but only to a degree. For example, one manufacturer allows certified contractors to purchase its components directly, but the contractors cannot buy the “latest” items. This leaves the contractors at a disadvantage in bidding on new projects.
We as consulting engineers work to minimize potential problems by only allowing those manufacturers who can supply user-friendly systems to bid on a project, but also we require them to show they have excellent back-up for providing ongoing service to the building owner.
Lee Norton, P.Eng. recently retired as a partner with the Mitchell Partnership in Burlington, Ontario. He is an editorial advisor to Canadian Consulting Engineer magazine.