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20 Questions About WACS Answered: Part 1

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

Web-accessible controls systems (WACS) were the cool and captivating draw in the building-automation section of the 2001 International Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo 2001) in Atlanta. The booths that had them available for display and demonstration were jammed.

The concentration of vendors and their demonstrations amounted to an electrifying short course in the integration of Web and building-systems technologies. HPAC Engineering took a look at many of the products and discussed their features with manufacturers’ experts staffing the booths. We were impressed by the simplicity with which WACS provide flexible, simple access to building-automation systems (BAS) and equipment-mounted controls from locations inside and outside of buildings. We were delighted to see that this technology has progressed to the point where cell phones and pagers, which now are standard equipment for owner-engineers, have become an integral part of alarming and alarm response.

The demonstrations inspired us to compose a list of 20 questions about WACS that designers and owner-engineers might ask. We have spoken with many of these individuals in the past and have a pretty good feel for what their concerns are. Some of their concerns likely are rooted in computer phobia, an inherent distrust of manufacturers’ claims of “simplicity” and “cost-effectiveness,” and/or a lack of understanding of the information technologies that are key to implementing WACS. Some concerns, however, are diplomas from the School of Hard and Expensive Knocks, earned from buying into new technologies too early.

The questions were sent not only to AHR Expo 2001 exhibitors, but to manufacturers who were not at the show. They also were sent to designers and owner-engineers to gauge their impressions and knowledge about WACS. The responses yielded a fascinating snapshot of an emerging technology that is simplifying a new and complex world of jargon and hyperbole while also paving the way for the Net-generation workers nipping on the heels of the current work force. This article is a frank but friendly discussion of the features and capabilities of WACS, as well as the challenges to which manufacturers will have to rise if they are to win the hearts, minds, and dollars of their customers.

1. What capabilities do WACS offer that conventional automation systems do not?

WACS provide full accessibility to building-automation systems through an ordinary browser, such as Internet Explorer or Netscape Navigator, without proprietary software being loaded onto every computer that is used to access the system.

“A WACS requires a single Web-server computer on site that runs software from the building-automation vendor,” Larry Haakenstad, director of sales for Alerton Technologies Inc., said. “But for access via a LAN (local-area network), WAN (wide-area network), or even remote dial-up, the user is able to simply use the standard Web browser already on the computer.”

“This,” according to Steve Tom, director of technical information for Automated Logic Corp., “effectively means that any computer on the network can be a building-automation workstation. And if the WACS is linked to the World Wide Web, it means that the user can access the system from virtually any computer in the world.”

Such ease of information access has led to a “paradigm shift” in the application of building-automation systems, Brady Nations, manager of business development for Johnson Controls Inc., said.

“Now it is possible to provide information to the ‘customers’ of the facilities staff, the occupants of the facility who may benefit from interaction with the BAS, but haven’t been able to do so in the past because it was cost- or technically prohibitive to do so,” Nations said. “Consider the scientist who has environmentally sensitive experiments going on in the lab. He might like to know at any given time, from any given place, what the current conditions in his lab are. The BAS has access to that information and can deliver it to the scientist at his home, his office, or any place he has access to a Web-connected appliance.”

“Just as possible,” Haakenstad said, “a tenant could monitor his or her own space.”

Another advantage of WACS is that they provide a higher degree of interoperability than do conventional automation systems, a benefit that is greatly increased in the presence of an open protocol, Tom said.

“The Internet itself is based on open protocols,” Tom explained, “and standards such as HTML and TCP/IP provide an open conduit for interoperability. At the very least, a user should be able to access two different vendors” WACS from the same Web browser. With only a slight effort and a skill set taught at most high schools, a user can create Web pages that combine data from multiple WACS into a single summary page. There should be no need to create custom Web pages, though, as WACS that utilize BACnet or other standard protocols can integrate data and control parameters from multiple vendors” equipment into a single user interface. If the WACS itself utilizes Internet standards such as Java and ODBC, the system is even more interoperable and is not tied to a single hardware platform.”

Also compared with conventional automation systems, WACS offer “better integration (with) existing-building wiring, which, in turn, allows for easier installs and lower costs,” Steve Ziejewski, a product manager for the Liebert Monitoring Group, said.

2. in what types of applications are WACS useful and cost-effective?

“It is hard to imagine an application where access via the Web would not be useful,” Bob Schultz, PE, director of applications services for TAC-Americas, said. While many respondents echoed that sentiment, several were more specific:

  • Raymond Rae, vice president of marketing for Delta Controls Inc., said WACS “are most useful whenever remote or global access is required.” In particular, Gordon V.R. Holness, PE, president and CEO of Albert Kahn Associates Inc. and a member of HPAC Engineering’s Editorial Advisory Board, said, they are effective “where buildings have no resident maintenance personnel or where a complex of multiple buildings are geographically separated from their central maintenance service (i.e., an urban college campus).”
  • In addition to “multi-site applications,” Ziejewski of Liebert said, Web-accessible controls are most useful for “’multi-user’ applications or where an ‘anytime-availability’ need is necessary.”
  • Jeff Bredeson, group manager of product marketing for North America for Invensys Building Systems, said “thin-client solutions” such as WACS are most effective in an intranet environment in which the server or source is available to all other PCs on the network. “Connectivity can be offered outside of the private network to the Internet,” he said, “but this may require additional security precautions (i.e., proxy server/firewall) and registration of public IP (Internet protocol) addressing.”
  • Kevin Osburn, vice president Apogee product marketing and development for Siemens Building Technologies, said the best use of Web-accessible controls is “primarily monitoring applications.”
  • Kevin Duffy, vice president of sales and marketing for Notifact Corp., said wireless WACS are best used “where a BAS is not; on smaller facilities such as convenience stores, shops, (and) office parks; (in) mission-critical applications; (and in) remote facilities and unmanned facilities.”
  • Paul Ehrlich, business-development leader for The Trane Company, said that typically, WACS technology “works best for viewing system data and changing setpoints and a few other basic operator functions.” However, “What this doesn’t work well for is storing large amounts of data, configuring a system, doing in-depth troubleshooting, and programming.”

As for cost-effectiveness, Tom of Automated Logic said, “There is no reason a WACS should cost more than a conventional control system.” A reason for this, Chief Engineer Mike Donlon and IT Strategist Rehan Kamal of Computrols Inc. said, is that: “Most buildings already support Internet service for other reasons. They have internal network wiring, firewalls, and an IT (information-technologies) staff.”

Rae said WACS “are most cost-effective on large sites with many users, where infrastructure already is installed.”

3. How do WACS impact construction scope, schedule, and budget?

The respondents were in agreement that WACS have virtually no effect on construction scope and schedule and--generally--only a minimal impact on construction budget.

“The Web enabling of the BAS is a minimal-cost item and fits into the schedule with the rest of the BAS implementation,” Nations of Johnson Controls said. “The only thing to consider is that it is planned into the implementation, not thrown in at the last minute.

A view of a chiller plant.
Image courtesy of Alerton Technology

“... If the WACS has software that resides on an IT server, and the IT department has space, it’s a no-cost issue,” Nations continued. “If the IT department says all departments provide their own server that must meet their minimum standards, there could be an impact, especially when their standards are high-end.”

Although a Web server likely will cost more than a single operator workstation (prices of Web servers start at under $1,000, according to Tom of Automated Logic), Ehrlich of Trane said, it may “be less expensive than buying and setting up three or four workstations.”

According to Rae of Delta Controls, time, manpower, and money can be saved during the commissioning process through the use of WAP- (wireless application protocol) enabled devices (Palm Pilots, Web-enabled cellular phones, etc.).

Although the project-management basics of WACS are virtually the same as those of conventional building-automation systems, it is important to note one possible exception: “The project-management team most likely will need to interface with the IT department for access to WANs and to make Web servers accessible to the outside world,” Haakenstad of Alerton Technologies said.

“This gets into the world of information and network security as well,” Haakenstad continued. “These same issues occur in any IP-enabled system regardless of whether it is Web-based or a typical client/server architecture that connects to a company’s WAN.”

4. What components of WACS are different from those of conventional BAS?

“This varies by vendor,” Osburn of Siemens said. “Ideally, the WACS solution uses the same ‘look and feel’ of the traditional BMS (building-management system) information. So training would be minimized and security would be the same. What is different can be the way in which connectivity is accomplished.”

“The device that connects (the control system) to the Internet may include a variety of functionality, from a limited message-routing service to a full-blown Web server and control engine,” Dennis Tuft, vice president of marketing for Tridium Inc., said.

Some vendors build servers into selected control modules, Tom of Automated Logic said, while some offer a software-based server that can be installed in any PC on a network.

“For a small, stand-alone system, the server and the browser can be installed in the same computer, so when the technician plugs his laptop into the control module, the laptop is acting as the server, creating the Web pages he sees on his browser,” Tom said.

More commonly, Tom continued, the control system will be connected to a computer network, with one of the computers acting as the server and making Web pages available to every other computer on the network. Larger systems may warrant a dedicated server: a PC with memory, disk capacity, and an operating system optimized for quickly providing Web pages to a large number of users simultaneously.

The open nature of a WACS enables large amounts of data from different sources to be presented as a comprehensive whole.
Image courtesy of Automated Logic Corp.

5. How are WACS integrated into a system design and ultimately specified?

“WACS can be integrated easily into the general system design by simply specifying that access shall be via a Web browser,” Haakenstad of Alerton Technologies said. “What may take some time is determining if the access is strictly via a LAN or a WAN or an ISP (Internet service provider) or ....”

“Often, this is a question to be answered by the corporate IT department where the system is installed,” Nations of Johnson Controls said. “Some departments have rigid rules that prevent connecting an internal system to the World Wide Web at all. Others are more flexible, yet still may have a rigid firewall that can be crossed only by an external device if it has the proper proxies on board. ...

“This raises the point about the relationship between the IT department and the facilities department,” Nations continued. “It varies from company to company. We’ve seen cases where the facilities department wants its own independent network because it’s worried about administrative and maintenance tasks performed by the IT department that could disrupt the operation of the physical plant. In other companies, the only option is to use a common backbone for all data systems.”

A wireless Web-accessible controls system can be integrated on the “equipment level,” providing an “avenue for additional functionality and savings,” Duffy of Notifact said.

When it comes to specification, the same rules that apply to conventional building-automation systems apply to WACS: Know what is available, decide what you want, and write it down, Tom of Automated Logic said.

“There are significant differences between the WACS offered by different vendors,” Tom said. “Look at what they have to offer and decide what features you need. Do you need the added security of Secure Socket Layer (SSL) communications? Which control functions do you need to access over the Web? Do you require use of an open protocol, such as BACnet, to provide interoperability with other vendors’ systems? Does your system need to support additional protocols, such as Modbus, SNMP, or LonTalk, in addition to its native protocol? Is your system large enough to require use of an enterprise-class database, such as Oracle or DB2? Is it desirable to have a platform-independent system that will run on Linux or Solaris as well as multiple flavors of Windows?”

Whether WACS are specified based on the level of system-interface functionality required, as Rae of Delta Controls suggested they be, or the same way that graphic-workstation capabilities are specified, as Osburn of Siemens recommended, the specification is driven by customer requirements, Ziejewski of Liebert said.

“The Web may not be cutting-edge technology,” Ziejewski said, “but since this is a well-known media, customers are demanding this type of interface.” Although the Web may no longer be cutting edge, it still is relatively new, and as with any new technology, writing specifications can be a challenge, Ehrlich of Trane said.

“Suppliers and consultants need to learn the new technology and create fair and impartial specifications,” Ehrlich said. “What typically is happening today with WACS is that the specifications are either vague or proprietary.”

6. How are WACS installed, activated, and tested?

“Installation should be accomplished centrally, alleviating the need to visit every user’s machine and install new software,” Osburn of Siemens said. “Activation often will require coordination with IT resources.”

That coordination, according to Nations of Johnson Controls, normally involves IT-standard procedures such as “assigning IP addresses (and) setting up whatever is needed to address firewalls, ISP connections, etc.”

The Web server should be tested “to assure all specified connection methods are operating and that the data on the Web pages is indeed the correct data from the field devices,” Haakenstad of Alerton Technologies said. For wireless WACS, that simply is “a matter of connecting equipment to a communication dataport, configuring at a secure Website, and sending a test message,” Duffy of Notifact Corp. said.

Web servers can permit offline programming using standard Web-development tools such as Microsoft Front Page, Donlon and Kamal of Computrols said. The key to this is that the building server also allows offline programming and simulation. With special building-automation software, the entire system can be programmed and simulated prior to installation. Also, all of the Web pages can be tested for connectivity. The pre-programmed system then can be shipped and commissioned on site without an on-site Web designer. Testing is strictly limited to the controllers, equipment, and field connections.

7. How are WACS operated and maintained?

Although the operation of WACS is very similar to that of traditional building-automation systems, engineer Bruce L. Billedeaux of Armstrong Service Inc. said, security is much more important with WACS.

“Traditionally, BAS security and passwords management has been very poor,” Billedeaux said. “This is a new facet of worldwide Internet integration that must be considered.”

A graphics view displaying a complete image of an air-handling unit.
Image courtesy of Computrols Inc.

The maintenance of WACS also is similar to that of conventional building-automation systems, Billedeaux said; however, if a separate server is used, the data interface must be updated when the point list is changed on the BAS component.

“The complexity of this update can vary from automatic to costly and difficult, depending on the equipment and vendor,” Billedeaux said.

Bredeson of Invensys said the operation and maintenance of Web-accessible controls systems is “vendor-specific.”

“Some vendors supply Web servers that host all the graphics and code,” Bredeson said. “Other vendors offer Web hosting at a remote site and charge subscription fees for this service. Maintenance often can be done on-line if the system has Internet connectivity.”

From time to time, the system interface will require firmware upgrades, Ziejewski of Liebert said.

Web servers need to be updated when equipment is added or spaces are modified, Haakenstad of Alerton Technologies said.

To Ehrlich of Trane, the question is not only how WACS are operated and maintained, but who will operate and maintain them.

“In theory, an owner could maintain such a system,” Ehrlich said. “In reality, it probably typically comes back to the installer to maintain it.”

Rae of Delta Controls agreed: “If the end user is technically proficient, he can maintain his or her own WACS. Otherwise, the industry norm would be to enter into a service contract with the installing contractor.”

In any event, Schultz of TAC-Americas said, “The task is not difficult for the individual with the right skills.”

8. What are the computer-hardware and software requirements of WACS?

Web-accessible controls systems require two things, Rae of Delta Controls said: a server—“any Windows machine with the Web-server application installed”--and a client—“any device with Web-browsing capability.”

Tom of Automated Logic said his company recommends a 500-MHz Pentium III (or equivalent) minimum platform for central Web servers. For user workstations, he continued, the company recommends a 300-MHz Pentium (or equivalent) minimum platform with an Internet Explorer 5.5- or Netscape Navigator 6.0-compatible browser.

“Some of our customers prefer the Linux operating system or Sun Solaris computers,” Tom said. “... In many cases, the server simply is a rack-mounted network PC with no laptop, monitor, or other peripherals. Users access the server over the network and perform any required file updates, system backups, etc. remotely from their PC.”

Donlon and Kamal of Computrols said Web-server PCs require a minimum 300-MB hard drive; a Pentium 300-MHz processor; 64-MB RAM; a 10 Base T network card; and Windows 98, NT, or 2000 software.

Nations of Johnson Controls said buyers should avoid WACS technology that requires the operator to build custom Web pages for information to be served to remote users.

“Technology exists that allows the WACS portion of the system to automatically read the BAS database,” Nations said. “Whenever a change is made to the database, it automatically is available to those accessing the system via Web devices.”

9. Are WACS a retrofit solution, or are they feasible only for new systems? Can they be bootstrapped onto an existing BAS?

“Most WACS have some sort of gateway (hardware or software) that links multi-equipment communicating protocols from existing equipment,” Sophie Vandebroek, vice president of technology for Carrier Corp., said. “If so, there is a retrofit possibility.”

How great that possibility is depends on the system being retrofitted, Tom of Automated Logic said.

“If you are retrofitting a WACS made by the same vendor as the original system, and that vendor has built legacy support into the WACS, it may be a fairly simple retrofit,” Tom said. “If the vendor does not offer legacy support, or if the WACS is made by a different vendor, then there will be some custom engineering required, and the retrofit will be more difficult. Essentially, this becomes an interoperability issue. The retrofit obviously will be simpler if the existing system uses a standard protocol such as BACnet.”

If a system is more than a few years old, it most likely will need a software upgrade to allow the BAS to get data to the server, Nations of Johnson Controls said.

Duffy of Notifact said wireless WACS are designed for both new and retrofit systems.

“Some WACS can be hard-wired to points or sensors or receive signals from a BAS to send out alarm messages or receive setpoint commands,” Duffy said.

Although bootstrapping WACS features onto an existing BAS is possible, “In all likelihood, it will only provide limited Web visibility of selected parameters,” Tom said.

“Whenever possible, the goal should be to replace the existing BAS with a front-end that was designed from the ground up as a WACS,” Tom concluded.

10. What actually is “on the Web”? Do you need to register one or more domain names?

“A WACS is capable of being connected to the World Wide Web, and it uses Web standards to provide the user interface, but it does not have to be on the Web,” Tom of Automated Logic said. “WACS can be limited to a single office network or a company intranet, if desired.”

Ehrlich of Trane said most WACS are installed on intranets and rarely, if ever, are on the public Internet or World Wide Web. Nevertheless, when WACS are “on the Web,” what actually is there is the software that enables users to configure and distribute messages and record and maintain information, Duffy of Notifact said.

Nations of Johnson Controls said “high-end BAS functions” such as DDC- (direct digital control) sequence configuration and system-display design are seldom performed via WACS, that they normally are done on engineering workstations.

Regarding domain names, whether or not one or more are required for a WACS depends on the access scheme, Bredeson of Invensys said.

“If the access is only meant to be offered through an intranet or VPN (virtual private network), then no domain names are required,” Bredeson said. “However, if the product is hosted at a remote site, and Internet access is required, then at least one domain name is required. In this case, there would need to be at least one public IP address reserved as well.”

If an organization already has a Web presence, Tom said, a WACS can be established as a subdirectory, or “cname,” of the organization’s existing domain.

“For example, could provide WACS access through the existing domain name,” Tom said.

Next month: answers to questions 11-20. Read 20 Questions About WACS Answered: Part 2 here.