Internet protocol (IP) is growing in popularity as a method for integrating building systems. First of all, it is a way of interconnecting every building system. According to Rawlson King of the Continental Automated Buildings Association (CABA), “The idea behind IP-based systems is that all devices should be able to be accessible regardless of function. CCTV, access control, intrusion detection, fire alarms, fire suppression, lighting controls and HVAC can all be integrated in IP-based systems.” In a CABA presentation originally given at the Intelligent Building Summit in 2006 in Toronto, there was a comprehensive listing of building systems that can be monitored and/or controlled through an IP-based system.
What does IP offer that is unique? First, once these building systems become nodes on a building’s IP network, they can all be programmed to interact in a variety of ways. The IP building network essentially is a network of networks. Each subsystem can be managed by its own controller or network of controllers, while the IP network can take care of conversations between them.
“IP is such a common networking protocol that almost every business in the Western world has an IP network,” said Denis Du Bois, editor of the online magazine Energy Priorities. “A trend in computing is a service-oriented architecture, or SOA. The basic concept is to connect intelligent devices to a network and enable those devices to serve their data to any other device that requests it. … Once a device is enabled for Web services, its functions and data are exposed and available on demand. Other systems can poll the data as needed for analysis and send commands back to the devices over the IP network. An HVAC controller might check with a motion detection subsystem to determine which rooms are occupied, then program changes on the thermostats in the empty rooms.”
These building systems can then be monitored, controlled or configured from any Internet-connected computer.
In theory, at least, this should be an ideal way to integrate building systems, but as with any theory, implementing it is the hard part.
An obvious application, for example, would be CCTV. If the surveillance cameras are linked through the Internet, you can view your office, factory or home from anywhere in the world. Premises monitoring using digital CCTV and DVRs is one of the applications of IP-based systems. It provides an ideal means to see what’s happening on your premises from a local or a remote location. A number of companies are producing IP-compatible cameras and DVRs. Since the Internet is already designed for large and rapid data flows, it is a natural for security video.
But there are advantages to having all of the other building systems running on an IP network, too. The interactions between the various subsystems can be programmed from a central computer that can access every one of them. Because each IP device, including subsystem controllers, has a unique address, any device can be called up through any computer with an Internet connection.
There are at least two levels of expertise required to set up such a system of systems. The integration level runs on the building’s internal IT network, usually Ethernet. This requires expertise in IT systems. However, IT technicians will most likely not be certified in setting up the HVAC or fire alarm systems, so different specialists will have to work together. Common to all of these systems and sub-systems is the electrical contractor, who must provide the power and wiring for it all. In fact, the soon-to-be-expanded capabilities of power over Ethernet (PoE) will enhance the ability to use Ethernet cables to distribute usable power for various devices, such as cameras and door access controls. Running these cables, which combine power distribution and IT data, will require the knowledge of both electricians and IT technicians.
There are two different approaches to installing IP control systems. For new installations, the simplest approach is to build all of the systems with IP--compatible devices. For already existing “legacy” systems, there needs to be a way of connecting the various control loops to the facility’s intranet. Johnson Controls, for example, makes available a central controller for tying together the devices and subsystems with its Metasys Network Engine, which is “capable of communicating directly to multiple field bus open protocols, including BACnet, LonTalk and N2Open,” said Terry Hoffman, director BAS marketing, Johnson Controls.
A major advantage of IP-based integration is that, once subsystems are accessible, their interactions can be modified as conditions change, as information on the various systems is gathered, as technology evolves, and as new integration software becomes available. The various building systems become, in effect, a living entity. There is no need to run new wiring or physically alter existing system components to tune their interactions. To my mind, this is the most important quality of IP integration. It will grow because it enables existing building systems to grow.
BROWN is an electrical engineer, technical writer and editor. He serves as managing editor for SECURITY + LIFE SAFETY SYSTEMS magazine. For many years, he designed high-power electronics systems for industry, research laboratories and government. Reach him at firstname.lastname@example.org.