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Reaching Beyond Four Walls

By Michael Cooper, PE, HarleyEllis

"The nice thing about standards is that there are so many to choose from."
-Andres S. Tannenbaum

In recent years, significant advances have been made in the technology of building management system (BMS) interoperability. This technology boost has resulted in a multitude of new BMS suppliers. While this certainly expands the opportunities available to facility executives and owners, it also helps create a more complex, ever-changing industry. The evolution of BMS is a key driver in the effort to integrate these systems into a single interoperable BMS.

Establishing The Groundwork

Before beginning an analysis of BMS advances, some key terms must be defined. Interoperable Control Systems combine controls of different manufacturers and communication protocols. These protocols could include BACnet or LonTalk (these concepts will be addressed later in this article). Interoperability occurs at the system level (i.e. central operation and maintenance work stations). [Editor's note: these protocols have been examined in several past issues of TFM. For more on BACnet and LonTalk, visit the archives at www.TodaysFacilityManager.com.] Such protocols are often referred to as "open" systems.

Integration combines several functional systems into one synchronous environment. Functional systems could include lighting, HVAC, security, and fire alarms. Integration could also include process (non-facility) related systems such as laboratory tests and measurement systems. Like interoperability, integration occurs at the system level.

Interchangeability is the capability of using devices of different manufacturers at the component level. "Plug and play" technology-replacing one component with another from a different manufacturer-is based on this concept.

Benefits Of Being Open

From the facility professional's perspective, there are three key benefits to open systems:

1. BMS is vendor independent. Owners retain the flexibility of multiple manufacturers throughout the life of the facility. There's no need for a commitment to one BMS supplier.

2. There is some level of confidence that compatible products can be incorporated into the system at a later date if needed. If one system supplier were to cease operations, others could fill that void and support the system.

3. Systems allow knowledge leveraging of existing information technology professionals. Much of the networking that is involved in creating open systems is analogous to that involved in typical office networks. IT professionals have been working with such systems for years and they can be a valuable resource to facilities personnel.

Software

There are critical software issues for facility professionals considering interoperable systems. Some of common software tools are:

OPC is an acronym for object linking and embedding for process control. This technology provides interoperability between control programs, automation systems, field devices, and business applications without excessive custom interfaces. Standards for data access and alarm/event handling are currently available. An historical data access standard is presently under development.

ActiveX is a set of technology rules governing how software programs should work together. This software is common in Internet applications. ActiveX requires a Windows-based computer system.

Java is an alternative to ActiveX, providing a similar set of governing rules. Java is not dependent, however, on the PC operating system and thus can be used on any system. XML stands for extensible markup language. This software focuses on the presentation of information and provides solutions for information display on portable devices (not PC monitors).

ODBC is an acronym for open database connectivity standard and allows software exchange between the keepers and users of data.

Commissioning Required

It is unlikely that designing and installing interoperable systems will be entirely standardized anytime soon. Thus, commissioning is necessary to ensure building performance is in accordance with the design intent.

Key points for commissioning interoperable systems include:

• Communication medium: LAN trunk, Internet, gateways, and routers;
• Addressing: control points, gateways, routers, and servers;
• Programming: control as well as maintenance of interoperability;
• Work station: consistent appearance, regardless of manufacturer or connection type; and
• Operation and maintenance: coordinate new hardware and software requirements with IT staff.

The Future Is Now

Interoperable BMS offer substantial benefits to facility managers and owners. They provide a degree of vendor independence, they instill confidence that compatible products can be found in the future, and they allow the knowledge of information technology professionals to be leveraged into this new area.

When considering open systems, be sure to focus on applications, maintenance, quality, and cost. Think about the building requirements and the level of open that is needed before discussing protocol options. For those facility professionals new to these systems, seek the help of a control systems integrator to help compile system options and relative costs.

Standard communication protocols and interoperability are not dreams; they are new, exciting technologies that will help propel facility management into the next century.