¬Ľ In the 1990s, the trend towards energy efficiency followed a pattern of integration from components to fixtures. The vision was to integrate the most efficient lamps, ballasts and lighting control methods into a single fixture. This later expanded to incorporate both facilitywide and occupant dimming for its effect on savings, flexibility, and worker satisfaction and motivation. This vision has been realized with a generation of 'intelligent fixtures' from manufacturers such as Cooper, Lightolier and Ledalite. Each manufacturer has chosen a distinct product strategy to provide real choices in cost and capability.

All intelligent fixtures integrate an intelligent dimming ballast that allows programming and control of individual fixtures, and connects them to a central or local interface, which allows a focus on the fixtures instead of on the control system. Depending on the manufacturer, models are available that integrate sensors for occupancy-based dimming or switching, as well as daylight and lumen-maintenance dimming. Together, these products present an effective way to increase application flexibility and worker satisfaction, while reducing energy costs and demand charges.

iGEN from Lightolier

In 2001, Lightolier announced its first intelligent fixture, Agili-T, which features plug-and-play installation, integral sensor technology, multiple optics and a control system that uses the existing LAN. At Lightfair 2003, the company unveiled a line of fixtures called iGEN that uses Digital Addressable Lighting Interface (DALI), an open protocol that controls the operation of ballasts.

iGEN is available as an option in most Lightolier brands, including linear, recessed, compact and select decorative fixture types. It represents more than 700 products able to cover most of the lighting in a typical commercial building.

The iGEN system starts with a digital ballast that is compatible with DALI. This enables all of the ballasts in a lighting system to be networked together and to control interfaces, such as networked PCs and wallbox controllers. Each ballast is given a unique address in the network so that it can be individually controlled or ganged in groups. For example, groups of fixtures can be told to dim to different levels according to the time of day. Occupants can also control local lighting through their workstation PCs, at nearby wallbox interfaces, or with handheld remotes. In addition, iGEN fixtures can talk back, providing energy monitoring capability and maintenance information, such as lamp and ballast failure alerts. Other controls can be integrated into the network, as long as they speak DALI. Many of these fixtures can also be specified with an integrated sensor to switch or dim based on occupancy.

'Using the standard DALI protocol, Lightolier is not inventing another system for the industry to figure out,' says Damon Wood, manager of market development for Lightolier iGEN. 'And as DALI installations proliferate, addressable lighting will become the norm rather than the exception. With multiple component manufacturers producing DALI-compliant products, concerns about proprietary solutions vanish. DALI is evolving to the point where virtually any degree of lighting control is possible.' He also sees DALI as a step toward lighting system integration (via a gateway) with building control systems that use BACnet, LonWorks, EIB and other protocols.

While digital lighting networks are often seen as complex, Wood believes iGEN overcomes this barrier. 'By putting the intelligence inside the fixture-using addressable ballasts and integrated sensors-complications regarding component compatibility and complex control wiring have been eliminated,' he says. 'Because the two-wire iGEN communication circuit is located in the same conduit with the line-voltage conductors, we can use five-wire modular cables to simultaneously connect the iGEN fixture to both power and digital communication circuits.' Using these cables, iGEN fixtures and controls can be easily added, removed or relocated.

'Our current data shows over 75 percent of commands are to lower light levels, not raise them,' says Wood. 'In addition, we are providing a platform for the future so that other energy-saving strategies can be implemented, such as load shedding or daylight harvesting. We want the owner to know that his investment will continue to grow as the technology grows.'

DLS by Cooper Lighting

DLS stands for Digital Lighting System, an option available across seven Cooper brands that enables the fixtures to be tied together in a multi-scene dimming control system via inclusion of an intelligent dimming ballast. This includes linear and compact fluorescent, incandescent and magnetic low-voltage fixtures.

Cooper's strategy was to introduce intelligence into these brands while keeping the specification process focused on the fixture. The specifier selects a fixture with a DLS ballast, then selects control stations and remotes as needed. 'The control intelligence resides in the ballast so the lighting design process and specification remain with the fixture,' says William Johnson, marketing manager for Cooper Lighting. 'And the system cost with DLS is in the fixture package, so only minimal additional cost is required for the control stations and remotes.'

The control system is comprised of the fixture/ballast, the IR receiver/control station and a handheld remote, which provide preset and occupant dimming capabilities. It is designed to work out of the box: each ballast is pre-programmed with five scenes, and is set for Zone 1 so the fixtures dim as a group; this can be modified through the use of a master handheld remote called the 'Wizard.' 'Sorcerer' or 'Apprentice' remotes allow occupants personal dimming control.

The fixtures are daisy-chained to wall- or ceiling-mounted control stations using two low-voltage wires. Up to 12 zones and 12 scenes can be programmed, and up to 10 control stations can be used for control of up to 250 ballasts on a single control wire run. Separate zone control (home-run) wiring is not required.

'DLS eliminates the complex wiring schemes normally associated with zone wiring,' says Johnson. 'Scalability comes into play when additional control stations and zone programming are needed. No special control wiring other than the T-tap daisy-chain is needed to add controls or fixtures up to 250 ballasts.'

He says that the elimination of separate zone control wiring makes DLS a good value for spaces where multi-scene dimming is usually considered too costly.

Cooper announced two new additions to the DLS option: an occupancy sensor interface and biaxial dimming ballasts. The interface allows the DLS system to work with any occupancy sensor and switchpack combination; the relay output of the switchpack is wired to the interface. Light levels during occupancy and non-occupancy can be set at the default mode.

Ledalite's Ergolight can be centrally controlled by software or locally by an occupant's PC. It also integrates an occupancy sensor for daylight dimming (top).

Ergolight by Ledalite

Ledalite Architectural Products' contribution to the intelligent fixtures arena is Ergolight, a direct/indirect optical system.

The Ergolight fixture, incorporating task-oriented (direct) and ambient (indirect) light components, was designed to provide 50 footcandles at the work surface while minimizing glare on computer screens. 'The standard approach to lighting a space is to bathe the entire space with 50 footcandles from wall to wall,' says Wiebe. 'This can be overkill, as most egress areas do not require this level of illumination.'

Based on the assumption that traditional troffer layouts overlight corridor and egress spaces, Ledalite recommends putting the fixtures over workstations, and allowing the indirect component to provide sufficient illumination for egress spaces and corridors. The result is a reduction in the number of required fixtures (up to 50 percent, according to the company), which can significantly reduce energy costs and overall life-cycle cost-an up to 70 to 80 percent reduction in lighting energy load.

Ergolight can be centrally controlled using software that also generates real-time energy reports for energy management purposes, and locally controlled at the occupant's PC for personal dimming control. Each fixture integrates a light sensor for daylight dimming and an occupancy sensor, which gradually dims before tuning off for unoccupied spaces.

Wiebe says Ergolight uses standard connectors and fits into standard T-bar ceiling grids for simple installation. The company designed software that employs easy-to-navigate icons and on-screen visual tools.

'Ergolight works well in both retrofit and new construction situations and with a client that is progressive in their thinking,' says Wiebe. 'It's still not a mainstream product, but it is definitely getting closer to that as time goes by.'

Craig DiLouie is principal of ZING Communications, a marketing communications and consulting firm specializing in the lighting and electrical industries. A former publisher of A|L, he is the author of many books and articles on lighting and electrical engineering.