BAS Anywhere, Anytime
Through laptops, hand-held devices and even cell phones, building automation systems have taken to cyperspace, revolutionizing the accessibility and convenience of building controls.
CSE: What are the main advantages of web-based building control?
WESTPHAL: The ability to monitor and control a building from anywhere, anytime with an Internet connection and off-the-shelf browser software is the main advantage. Secondly, the cost of the browser software to display the web pages is free in Microsoft's Windows operating systems.
LUNDSTROM: Web-based systems also can provide easier remote access to building controls for site managers and operators for troubleshooting during off-duty hours, assuming the IT department allows access via firewall ports. And the amount of time required for training building controls operators is significantly decreased, because most people are already knowledgeable about using web-browser software.
TOM: I believe the primary advantage is a revolutionary improvement in accessibility. In the past, few people knew how to use the BAS, which was located at special workstations, and it was not uncommon for technicians with limited access to "fix" problems by locking points or bypassing the system altogether.
Today, engineers, supervisors and managers can access the system from their desktops; technicians can access it from a laptop, using a wireless network or one plugged into an Ethernet jack in the mechanical room; contract service personnel can access the system from their office, saving the cost of a site visit; and a consulting engineer can analyze problems from halfway around the world. The upshot is, with more eyes looking at the system, it's much harder for an unmotivated employee to get away with quick-fix solutions that compromise the system.
A second advantage of web-based systems is that they use Internet technology. Previously, even the largest HVAC control manufacturers had only a handful of R&D engineers working on the BAS user interface. Now, an army of engineers in Silicon Valley and elsewhere is developing new technologies for the web, many of which are directly applicable to a web-based BAS.
CSE: Has it had any effect on the interoperability?
TOM: For years, engineers have talked about implementing energy management schemes based on time-of-day pricing, incorporating weather forecasts into ice-storage plant management, integrating building security and control systems, and other applications that require links between multiple computers. These schemes have always been possible, if one had compatible computers and programs and unlimited budget to write the integration applications. But now technology has made it practical to implement this between a wide variety of computers and applications.
CSE: How popular has web-based building control become in the past couple of years?
WESTPHAL: An optional, web-based user interface has become a fixture in many job specifications recently, because most BAS manufacturers offer this feature as part of the product line. Indeed, some BAS manufacturers use it as the base for their user interface. It is also specified because, in most cases, it is a premium feature of the BAS and adds to the manufacturer's revenue.
LUNDSTROM: Given the choice, owners will select web-based building controls over software-based PC platforms 99% of the time. Consequently, almost all major vendors have some type of web-based solution. Now there are even small, hardware-based platforms for $1,000 to $1,500 that have embedded web servers and can be rail-mounted in the same enclosure as the building controller, are connected to the controller LAN and IP network, create web-based graphics, set time scheduling and have trend logging and alarm management.
CSE: How thoroughly has the issue of network security been addressed with these systems?
LUNDSTROM: Security is improving, but much is still left up to the owner's IT department. Because most of the systems are Windows-based, they have standard Windows security issues. And even some of the network-area controllers that can be configured as web servers have embedded Windows-based operating system platforms, which, if not protected, are susceptible to worms via network connections.
TOM: A facility's web-based BAS needs the same protection as any other web server on the network. However, the more common and frustrating situation is where an end user already has multiple web servers on the network, but the IT department balks at providing an Internet connection for the BAS. This is primarily an education and coordination issue. The IT department needs more information about the BAS, and they need to give it the same level of protection they're providing for other web servers. Furthermore, if one is planning to use any portion of the IT network as part of the BAS, whether or not it's a web-based system, it's necessary to coordinate with IT early in the planning stages and keep them in the loop throughout the project.
CSE: What about reliability? What ensures that operators can still manipulate building controls if the system goes down?
TOM: One should take the same steps as with a conventional BAS; one must have a distributed control system with standalone controllers that can keep the buildings comfortable, turn systems on and off according to a schedule, and otherwise continue "business as usual" until network communications are restored. And an operator access port on every controller is required so a technician can plug a laptop computer or other handheld device into the controller and make necessary changes. A local operator's terminal can be a convenience in this situation, but it doesn't eliminate the need for a local access port. Typically, a local terminal can be used to check status, edit setpoints and schedules and perform other routine functions, but if one needs to change the operating program or make other major changes, a local access port is required.
LUNDSTROM: To improve reliability, and to ensure local override control if the system goes down, owners and engineers should consider the following:
First, carefully consider where the web graphics reside and review the architecture of the system. Based on the vendor and platform, one may have varying options of what creates the graphics, including a single web server, multiple web servers, single or multiple network controllers with web services and web-enabled hardware servers. If reliability is an issue for an owner, options that offer multiple web servers or devices provide improved reliability over a single system.
Second, minimize building controls programming logic at the server or network controller levels. No one is interested in losing multiple building control loops if one server or network controller goes down while performing some critical calculation.
Third, make sure there are local network connections for the controller LAN so if the web server or IP connection is lost, it is still possible to manipulate building controls.
CSE: What's the latest in user-friendly graphical interfaces for BAS?
LUNDSTROM: It includes everything from simpler menus, 3-D animated graphics, color-changing backgrounds, photographs, embedded trend graphs and hyperlinks to manufacturers' data sheets, CCTV/webcam images, links to electronic as-builts and O&M manuals, and even CNN and Weather Channel broadcasts.
Larger owners are developing building-operation control centers where they have consolidated all BAS graphical interface operations in a single large room with multiple operator consoles in order to monitor, control and operate everything from HVAC to security to fire-alarm/fire-protection systems and other building operations.
TOM: Graphics should help the operator understand what the system is doing as quickly and as intuitively as possible. This being the case, animation has proved useful for helping users see what's happening, such as a spinning fan or a damper that shows the actual position. However, animation can be detrimental if it distracts users or highlights irrelevant information, like a flashing "Eat at Joe's" sign or condensate dripping off a coil.
Slider controls are another useful feature, if they're easy to adjust and give the user the resolution he or she needs, but sometimes it's nice to have the option to type in a specific setting instead of trying to fine-tune a slider. Consequently, a good graphical interface will let the user do both. It will also give the user the most important information at a glance and provide a way to drill down for details.
CSE: How practical are PDAs or other palm devices with regard to monitoring and controlling BAS?
WESTPHAL: I don't believe PDAs are all that practical. The cost differential between a low-end laptop computer and a PDA is quite small, but the usefulness and capability of the laptop far exceeds that of the PDA. At this time, it is more of a specification item and not that practical for an involved operator.
TOM: I think that as a supplemental interface, they're fantastic. A PDA is perfect for HVAC technicians, as they can receive alarms, change set points, restart equipment and perform hundreds of other tasks on the go. Also, most test-and-balance technicians, for example, would rather carry a PDA than a laptop, if it's got a well-designed interface that lets them step through the required testing, adjusting and documentation tasks. On the other hand, energy engineers, system managers and other users who primarily operate out of an office need the large graphics and full keyboard interface that only a PC can provide. The challenge is to determine what information needs to be presented on the PDA interface. If one tries to port everything from the PC interface onto a PDA screen, the user will be overwhelmed, so PDA screens need to be as carefully designed as the PC interface.
CSE: What kinds of tasks are building operators actually utilizing?
LUNDSTROM: Operators are using PDAs and text-messaging cell phones for monitoring alarms and building conditions. Functionally, the current PDA devices can provide basic monitoring, alarm handling and operation via simple menus and scaled-down graphics. They give the advantage of longer alarm messages and detailed information, as compared to small pagers. However, PDA display size and resolution still limit them from providing equivalent graphics to a desktop.
CSE: In what ways does technology need to improve before web-based building controls become more widespread and utilized in the industry?
LUNDSTROM: There is still some difference in the functionality offered via web services-based technologies and the more traditional front-end architecture using a web interface. The focus is on using XML technologies to provide a common data exchange, but care should be taken to understand what data can be exposed to web services. Owners should not expect that a particular system will give them full monitoring, control, trending and engineering via a common web browser just yet. The reality is that web services were not specifically designed for real-time monitoring and control. However, the future looks bright.
More and more, mechanical systems offer factory-installed controls with pre-installed, pre-programmed, web-based hardware servers, ready to be integrated into a facility-management system with a simple IP connection. Small tablet computers with Wi-Fi connections will replace web page-cropping PDAs and run web browsers, e-mail clients, instant messaging, VoIP and other applications.