Integrated Building Equipment Communications System (IBECS) Network Build-Out

Results:
The objective was to test the reliability of the IBECS communications network operating in a realistic, uncontrolled office environment. We installed a sufficiently rich set of actuators and sensors to make this a realistic test of how well the network concept allows communication between components to control lighting and envelope systems. The components and network cabling were installed, and work is now progressing on developing control software that will implement the lighting and window control strategies and simplify the commissioning process.

Left: Control panel for eight light fixtures in open-plan office. Right: IBECS-controlled electric lighting fixtures where each fixture is individually controlled to user settings. IBECS Venetian blinds are to the left in this photo.

Lessons Learned
The prototype network interfaces enable a user to control and monitor, from a variety of sources including the user's personal computer, the condition of various dynamic fenestration system and lighting systems. By creating a functional specification for an IBECS network interface and testing a prototype, we demonstrated that such an interface can be constructed and developed an understanding of cost-effective price per point.

The added cost for networking from the original equipment manufacturer (OEM) is approximately $3.75 per direct-current (DC) motorized shade. This cost will be the same for alternating current motors. For multiplexed electrochromic (EC) windows, the OEM added cost for networking is $1 per window. Commissioning of the IBECS network system is not required, and flexibility to reconfigure the control layout and grouping of window systems over the life of the installation is maintained. This IBECS concept is appropriate for the dynamic window industry.

The IBECS concept is compelling because costs can be reduced if control integrated circuits (ICs), which typically reside on a single device, can be implemented upstream in software. This is the case for zero- to 10-volt(V) DC controllable electronic ballasts where real-time operations of the devices are not compromised by the speed of the network. The ballast controller, which typically regulates numerous ballasts, can be eliminated with the IBECS system and replaced with software upstream at a higher level. With motorized shades and EC windows, however, the complex details of actuation (e.g., "change tilt angle, check, change tilt angle, check...") are best realized at the local micro-local area network (LAN) level, downstream of the IBECS network and next to the device so as to ensure proper real-time operations. The IBECS concept is still compelling for this class of devices. Global commands can be sent through the IBECS network to actuate individual devices (e.g., "go to tilt angle to 30°") and device status can be monitored over the IBECS network. Control algorithms that integrate window and lighting systems (and their respective environmental sensors and actuators) can also be implemented in software upstream of the microLAN.

Downloads and Links:

• "Standardizing Communication Between Lighting Control Devices: A Role for IEEE P1451." Rubinstein, F., S. Treado, P. Pettler, October 2003. (1.8 MB, 9 pp)
   

Contact: Francis Rubinstein, Lawrence Berkeley National Laboratory (LBNL), (510) 486-4096