Latest from Building Automation

20 Questions About WACS Answered: Part 2

May 1, 2001
Manufacturers and engineers weigh in on an emerging technology: Web-accessible controls systems

This is Part 2 of a 2-part series. Read 20 Questions About WACS Answered: Part 1 here.

Inspired by the tremendous interest in Web-accessible controls systems (WACS) observed during the 2001 International Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo 2001) in Atlanta, HPAC Engineering composed a list of 20 questions about WACS that designers and owner-engineers might have. Those questions then were sent to more than a dozen manufacturers, as well as a few designers and owner-engineers. In April, we published responses to the first 10 of those questions. Following are responses to the other 10.

11. Can Web accessibility be provided by a third-party supplier? Can a WACS “integrate” multiple BAS or controls products?

“Today, Web-access tools come from the BAS manufacturer,” Brady Nations, manager of business development for Johnson Controls Inc., said. “This is not likely to change in the near future because the manufacturer knows the requirements for interfacing with their specific system.”

In theory, a WACS enabling device manufactured by a third party that can connect to any BACnet-compliant system is possible, Nations said; however, “Standards continue to be moving targets that result in different methods of implementation by manufacturers.”

To the extent that they support interoperability, Steve Tom, director of technical information for Automated Logic Corp., said, existing building automation systems and controls products can be integrated by a WACS.

“If the equipment vendor is willing to share data with the WACSÑand especially if the data is available through an open protocol such as BACnetÑthen the integration can be relatively simple,” Tom said.

Larry Haakenstad, director of sales for Alerton Technologies Inc., said a WACS can integrate products from other companies as long as its Web server can communicate with them.

Chief Engineer Mike Donlon and IT Strategist Rehan Kamal of Computrols Inc. said there is BAS software that can integrate equipment from multiple manufacturers independent of the Web product.

“This, in turn, can be placed on the Web,” Donlon and Kamal said. “So, although (the) Web product can be used to integrate multiple vendors, this capability has nothing to do with the Internet access itself.”

Some Internet-ready controllers, “on the other hand, were made to have completely open Internet connectivity right down to the controller level,” Donlon and Kamal continued. ÒWWW access is available at the controller level for human-to-controller access. But more importantly, XML and other standards are being used for truly open, third-party controller-to-controller connectivity.”

Kevin Osburn, vice president of Apogee product marketing and development for Siemens Building Technologies Inc., said a WACS cannot directly integrate multiple building automation systems or controls products. However, once integration between two such systems or products is established, a WACS should be able to Òseamlessly provide” consistent monitoring of them, he continued.

12. Can WACS be hacked by outsiders or unauthorized insiders?

“Security is a relative quantity,” Donlon and Kamal of Computrols said. “Vendors (who) say they provide access to the entire world while providing absolute security are in denial. Is there any bank that cannot be robbed? Extremely secure military facilities have their network security compromised regularly. The question is how easy is it and what damage can be done.Ó

Unauthorized insiders pose a much greater threat to WACS security than do outsiders, and in this respect, WACS are no more or less vulnerable than are conventional building automation systems, Tom of Automated Logic said.

“If the WACS doesn’t provide multiple levels of access with tighter control of critical building functions,” Tom said, “if the WACS doesn’t provide a way to give each operator a unique login and track that operator’s activities, and if the system administrator doesn’t keep an eye on who does what and isn’t vigilant about deleting logins of ex-employees, then the unauthorized insider poses a threat.”

Osburn of Siemens disagreed: “Given that WACS use sophisticated means to secure access, IT people still will be more concerned with Internet access than (with) intranet access.”

That users are limited in the tasks they can perform provides some protection, Paul Ehrlich, business-development leader for The Trane Company, said.

“Being on a shared network is always riskier than being on a dedicated network,” Ehrlich said, “but these risks are balanced by the potential rewards.”

“Fortunately, the technology being used to develop WACS applications is the same technology used in the most critical data systems,” Nations of Johnson Controls said. An example is Secure Socket Layer encryption, which Tom explained, “is widely used to protect credit-card transactions and other financial communications on the Web.”

Donlon and Kamal of Computrols said protection can be provided by first setting up standard Linux firewalls.

“All BAS components use intranet connections that are behind the firewall and protected from actual Internet connections,” Donlon and Kamal said.

Next, secure connections over the Web and encrypted transmissions between the Web server and the building server are made to further discourage “attacks from within the firewall,” Donlon and Kamal continued.

The third step in providing security for WACS involves limiting functionality from the Web server to what is needed from the Web clients.

“Even if Web access is accomplished by hackers, there is a limit to what they can do,” Donlon and Kamal said.

Finally, incoming IPs are limited to specific addresses or ranges of addresses.

“This offers one of the best defenses available,” Donlon and Kamal said. “It allows only connections from known computers.”

13. Can information entering or leaving a WACS server be “tapped”?

Although electronic eavesdropping is possible, it is “unlikely” thanks to encryption techniques available with server software, Raymond Rae, vice president of marketing for Delta Controls Inc., said.

“Those eavesdropping on the LAN or at the ISP will have a very difficult job in making sense of any snooped data,” Donlon and Kamal of Computrols said.

Even if they can make sense of it, Ehrlich of Trane said, it will be “pretty mundane information, such as temperatures, pressures, and setpoints.” “We aren’t talking about account numbers, financials, or the score of Tomorrow’s big game,” Ehrlich said.

Encryption “also prevents active attacks where unwanted parties try to actively make changes in the BAS system,” Donlon and Kamal said. “This is because ... encryption algorithms also (can) employ authentication techniques.”

In the case of wireless WACS, communications are encoded, Kevin Duffy, vice president of sales and marketing for Notifact Corp., said.

“Packets of information are sent over secure wireless channels in milliseconds at random times and are unintelligible to virtually anyone,” Duffy said. “This is a distinct advantage over phone systems, which have a continuous data stream.”

14. What features do most WACS share?

WACS share an “ability to provide control-system data in a format that can be viewed and edited through a Web browser,” Tom of Automated Logic said. “Beyond that, the features vary widely.”

Bob Schultz, PE, director of applications services for TAC-Americas, said all WACS provide the first level of Web interaction--monitoring, which involves “the remote access of data, the ability to see what is going on in a facility”--while the second level--control, “the ability to override automatic control or to invoke different modes of operation”--is available only in select products. As for the third and final level of Web interaction--editing, “the ability to change the logic of control”--Schultz said he does not see it “as an offering of browser-based access.”

Sophie Vandebroek, vice president of technology for Carrier Corp., was more specific, saying that, “Most WACS share a translator or transcoder to decipher the multi-equipment protocols and provide a common management interface and access to an Internet Service Provider or WAN,Ó while Duffy of Notifact said most WACS are Òphone-line-based.”

15. What distinguishes WACS products from each other, and how can they be compared?

“You could easily fill an entire article or a series of articles with this question alone,” Tom of Automated Logic said. Still, that did not stop Dennis Tuft, vice president of marketing for Tridium Inc., from identifying three primary distinguishing features of WACS:

  • Where the information lies (in a central server or in servers at every site).
  • What can be connected (only the manufacturer’s products, only “one-technology” open products, or a multitude of different manufacturers’ products and different communication protocols).
  • Whether a Web interface is merely tacked onto existing heavy-client BAS software or the WACS truly uses Web technologies and provides access from “zero-client” Web browsers.

Rae of Delta Controls said WACS products can be distinguished from one another by comparing: cost vs. functionality, graphic/Web-page creation, data access from enterprise-management systems, ease of use, flexibility, and scalability.

Above all else, Nations of Johnson Controls said, it is important “that the buyer of a system understand the distinction between the features the Web access provides and the features the BAS provides.”

“Web access is a small component of the overall operation of a facility,” Nations said. “The most significant thing it offers is remote access via paths and devices common to the IT infrastructure.”

16. Does a WACS track who is using it and when, and how are access limitations achieved?

To the question regarding a WACS’ ability to track who is using it and when, responses ranged from “yes” (Notifact, Delta Controls, Liebert, Carrier, and engineers Bruce L. Billedeaux of Armstrong Service Inc. and Gordon V.R. Holness, PE, of Albert Kahn Associates Inc.) to “varies by vendor” (Invensys, Alerton Technologies, Tridium, Siemens) to "not typically" (Trane).

Tracking “is not an inherent feature of WACS, but it’s a feature every WACS should have,” Tom of Automated Logic said. “Ideally, the WACS not only should track who logs in and out, but record any changes they make to the system.”

Tom said access limitations typically are achieved by means of the operator’s login.

“Some operators can only view data,” Tom said. “Others can edit set-points, schedules, and other day-to-day operating parameters. Fewer typically will be authorized to edit the control programs themselves or to make major changes to the system configuration. The ability to silence, acknowledge, and delete alarms is another privilege that can be given to selected individuals.”

These privileges may be global or regional, Tom continued.

“By this, I mean an operator may have the authorization to view and edit parameters across the entire system or only in a certain building, on a certain floor, or in a certain room within the system,” Tom said. “With ‘fine-grained’ access control, privileges can differ from area to area. This means a user may be able to view the entire system and have fairly extensive editing privileges within one specific area of the building and more limited editing privileges in other areas.”

17. If a system needed to be modified substantially, who would perform the work, how much would it cost, and how long would it take?

The building-controls industry has changed dramatically over the past few years, moving away from the concept of “one riot, one ranger” to a “greater segregation of skill sets,” Schultz of TAC-Americas said.

“The individual commissioning the hardware and basic logic most likely will no longer be the individual who sets up the front end, graphics, Web access, etc.,” Schultz said. “As a result, a change to the physical plant now will generate work for several individuals.”

Generally, however, the installing contractor would perform a substantial modification to a WACS, Haakenstad of Alerton Technologies said. How much that would cost and how long it would take depends on the system and the scope of the changes, several respondents said.

18. Does a WACS replace conventional workstation software, and can one back out of a WACS if he does not like it?

To the question of whether WACS replace conventional workstation software, responses varied greatly.

Web access only expands the reach of a conventional workstation--it does not replace it, Schultz of TAC-Americas said.

“Web access does not provide all the functionality a facility operator requires to fully operate the BMS,” Schultz explained. “... The editing function most likely will remain at the operator station.”

Rae of Delta Controls agreed that a WACS is not a replacement for conventional workstation software, saying, “Conventional software typically is faster and loaded with a lot more features than the WACS software.” Ehrlich of Trane said that even with a WACS, workstation software is “needed to set up, program, and troubleshoot a system.”

Osburn of Siemens said that whether a WACS replaces conventional workstation software depends on the user.

“For those users (who) only need to do basic monitoring, the WACS is fine,” Osburn said. “For more-advanced users and those (who) do system configuration/engineering, (the answer is) no.”

Engineer Billedeaux said the deciding factor is the vendor chosen.

“In the installation I am specifying, there will be no operator terminal,” Billedeaux said. “The local operators will use laptop computers to log into the network and use Web browsers to view data. There will be much vendor equipment, and that normally would require five or six client software packages. Using a WACS server eliminates this need.”

Tom of Automated Logic said only a “true” WACS can replace conventional workstation software. Jeff Bredeson, group manager of product marketing for North America for Invensys Building Systems, and Steve Ziejewski, a product manager for the Liebert Monitoring Group, agreed, although Ziejewski said he “can envision where the local system is ‘out-of-band’ and not reliant on the network architecture to operate and where the WAC software resides at a higher or separate level.”

Nations of Johnson Controls said the question cannot even be considered in a general sense, as, “The answer depends on the functional requirements of the BAS, the needs of those who use it, how the use varies from individual to individual, and the manufacturer of the system.”

As to the question of whether a WACS can be backed out of, the respondents were in agreement that it can. Although Schultz and Rae maintained that backing out of a WACS can be done easily, Tom said the degree of difficulty depends on what was installed previously. If the WACS is fully compatible with the previous generation of field hardware, backing out of the WACS could be as simple as downloading the original software into the field controllers and reinstalling the conventional workstation software, Tom said. But if vendors were changed and field hardware was replaced as part of the WACS, it would be more difficult to back out of the WACS, Tom added.

19. Other than office and portable computers using Internet connections and browsers, what mobile devices can access WACS?

“Any device that can access the Web can potentially provide a WACS interface,” Tom of Automated Logic said. “Cell phones, palm computers, two-way pagers, Web Pads, Web TV--the list is long already and is growing longer every day.”

One of the most exciting things about WACS is that they are bringing building automation systems into the mainstream of Web technology, Tom said.

“Gadgets that Silicon Valley is developing today to help stockbrokers track their portfolio also will help building managers track their return fans,” Tom said.

What needs to be considered when applying WACS technology is the minimum level of functionality that will be needed by users accessing it via a Web-enabled device, Nations of Johnson Controls said.

“A cell-phone screen doesn’t present much data and can require a lot of finger work to do anything more than access a few points worth of data,” Nations said.

Still, Tom said, “The potential is unlimited.”

20. Where is the technology going, and what is on the near-term horizon of development?

“There is no question that remote access via Web technology will continue to be more prominent in BAS systems as time goes on,” Nations of Johnson Controls said. “Development organizations are working with the security issues and the ways to make it easier to apply this technology as it evolves. How far will it go? As far as the information industry takes it.”

“Opening up” the potential for remote access will be the continued development of wireless technology, Vandebroek of Carrier said. Increased “use of wireless hand-held/small devices,” Osburn of Siemens said, “will make access to your BAS anywhere (at) anytime a reality.”

Tom of Automated Logic said he foresees a day in the not-too-distant future when, “A technician on top of a ladder who has just replaced a VAV box will be able to flip open his cell phone, run the box through its paces to make certain it’s working correctly, and get directions for his next service call via the wireless Internet.”

Whether it is through wireless or wired links, Schultz of TAC-Americas said: “In a small number of years, all buildings will be connected to each other and some form of the Internet or a corporation’s intranets. ... This technology will signal the death of the dial-up modem, an out-of-date technology that most people will not be sad to leave behind.”

Nations said he foresees advanced application engines that interact without human intervention and make decisions that improve the operation of facilities.

“Consider the example where the operator is curious if his or her facility is performing at optimum levels of energy use,”Ó Nations said. “Rather than go through a rigorous analysis on his or her own, the operator would identify a remote application engine to the system. Communication between the two would be completely transparent to the operator. The remote engine would analyze the parameters of the facility, consumption patterns, etc. and recommend or automatically implement changes in operational sequences.”

Donlon and Kamal of Computrols said they see the building-automation industry going the way of Internet appliances.

“That is, TCP/IP connection to every single device in the building--not just the front-end computers,” Donlon and Kamal said. “... Standards such as BlueTooth, Universal Plug and Play, Jini, HomePNA, and others will drive Internet connectivity in the coming years. Internet-appliance technology will reach wide acceptance and become commonplace by 2005.”

Tom said: “The migration of building-automation functions onto the Web will make it possible to utilize other data from the Web to optimize building control. Want to use the weather forecast to decide when to precool a facility? That’s available from Need to incorporate the current electrical rates into your chiller optimization? Chances are your local utility company already has this information on the Web or would be more than willing to place it there because it would benefit both of you to do some demand limiting. Want to hire an energy consultant in Maryland to optimize the operation of your facility in Fairbanks? Chances are it won’t even cost you a plane ticket. He can gather all the data he needs over the Web, and if you give him the authorization, he can implement his recommendations without ever donning a pair of mukluks. Is the fan belt on AHU-5 nearing the end of its service life? Your WACS can keep track of its service hours, use ODBC to coordinate with your material-inventory database, check the Websites of several pre-approved vendors to find the best price, order on-line, and have the new fan belt waiting when it spits out the maintenance order.

“When will these developments become commonplace?” Tom asked. “Some are available today. Some never may prove practical, but, in the meantime, several new developments we never even dreamed of will make your WACS an even better tool than it is today.”

It is important that designers, buyers, and specifiers not allow information tools and technologies to blur the requirements of a BAS, Nations of Johnson Controls said.

“If the BAS does a poor job of operating a complex central plant, whether it is because the system doesn’t have the necessary features from the factory, or it has not been applied properly, it won’t matter if the management is notified of poor performance via the most-advanced workstation, a Web appliance, or a piece of paper sent in the mail,” Nations said. “They’ll still be unhappy.”

It also is important to remember, Tom of Automated Logic said, that while the movement of building-automation systems to the Web will bring “remarkable changes” to the HVAC industry, some things will never change.

“Building managers already are harried, overworked, and swamped with information,” Tom said. "A conventional BAS already can provide most of them with more information than they have time to look at. A WACS that provides access to fire- and security-system data in addition to the sea of HVAC data will be of little benefit--even if they can access it over the Internet--unless it also filters the data, separates the nuggets from the chaff, and uses color, graphics, and an intuitive interface to present the data in a form that is easy to comprehend. ...

‘In short,” Tom concluded, “the technological features of WACS are astounding, but the most astounding capabilities in the world are useless if they don’t get used.”