Minneapolis, USA
In 2002, the Minneapolis Convention Center (MCC) was expanded to nearly double the size of the original complex that opened a decade earlier. The new Center included two immense (100,000 square feet) exhibition halls, a versatile 3,400-seat auditorium (changeable into several smaller theaters), 33 meeting rooms (changeable into 4 larger rooms), a new kitchen and storage facilities, and a column-free pre-function lobby spanning 34,000 square feet.
This increase in floor space to almost a million and a half square feet required a massive effort in lighting design and installation. The new areas alone required more than 6,000 channels of dimming and relay control. In addition, 3,000 relays from the older facility needed to be linked into the new lighting system. To meet the Schuler and Shook design firm’s state-of-the-art lighting system requirements for the Convention Center, a facility-wide lighting control system was created by a single supplier, Leviton Manufacturing. This system permitted almost any light in the entire complex to be controlled and scheduled from a single PC or laptop computer, including dimming and relay switching of architectural and theatrical lighting.
THE EXHIBITION HALLS
The design of the exhibition hall lighting required both switched 277V HID Hi-Bay lighting and 120V dimmable incandescent quartz lighting. A portion of the quartz lighting was also designed to function as emergency lighting. Leviton relay cabinets were supplied to operate the HID lighting with 2 to 3 fixtures per relay while the quartz lighting was connected to I96e and I 24e Dimmer Cabinets. The quartz emergency lighting design needed to address the restrike time of the HID lighting. This issue was resolved by installing a time delay relay after the phase loss relay. In the event of a power loss, the I24e delivered emergency quartz lighting at full brightness. On resumption of normal power, the quartz lighting remained on full brightness for 20 minutes to allow the HID lighting to restrike. The exhibition halls were designed with D8000 10-Button Entry Stations slaved to Smart Jacks in the same manner as the meeting rooms. Similarly, several Ceiling IR Receivers were installed on the bottom of the catwalks for infrared handheld remote lighting control.
THE MEETING ROOMS
The expansion added 33 new meeting rooms. They were arranged in three clusters of 10 rooms (2 x 5) and one cluster of three rooms (1 x 3) with movable partitions between all adjoining rooms. Every cluster included an inscribed metal plate indicating its layout and a lighted push-button switch for control of each movable partition. Each panel was connected to a Leviton D8000 Contact Closure interface to accommodate room combinations.
All meeting rooms were equipped with a D8000 10-Button Entry Control Station — a Controller that can be used to control local and remote loads on the network — at the main doorway slaved to a D8000 Smart Jack — a Decora-style jack required to hook up a PC to the network to run Setup software — mounted directly below it. The Entry Stations for each room provided 5 standard lighting control presets, labeled 1 through 5, as well as max, raise, set, lower and Off buttons. When meeting rooms were combined, similar loads affected by these standard presets acted in unison. The Smart Jack permitted plug-in of a portable D8000 LCD Station for programming and remote control. Each room was also outfitted with a ceiling-mount IR Receiver slaved to the Entry Station to provide additional control from anywhere in the room through use of a simple infrared handheld remote.
A mixture of 120V incandescent and fluorescent dimming loads was specified for the meeting rooms. The Mark X™ ballasts specified for the coves required a single circuit of dimming while the Eco-10® ballasts specified for the down-lights required both a switched and a dimmed circuit.
Normally, Leviton would have used their MDS or a-2000 Dimming Cabinets for this type of application. But, due to the size constraints of the electrical closets in which the dimmers were to be installed, Leviton’s Colortran I96e and I24e High Density Dimming Racks were installed instead. These I Series Dimmers were initially designed for theatrical applications and required the ability to drive fluorescent loads properly. Accordingly, new software was written to allow them to drive Mark X™, Hi-lume® and Eco-10® ballasts with the precise dimming curves required. The resulting software is now standard with these products. The I24e Dimming Rack also featured an emergency power feed to operate only the cove lights. A phase-loss sensing relay was designed in and fed with normal power. This relay could assert the panic input of the I24e, causing the cove lighting to go to full brightness when normal power was lost, regardless of the current control signal status of the affected lights. At the same time, the I96e rack was fed with normal power and connected to all the meeting room loads. As the I96e and I24e Dimming Racks use the same DMX512 control signal, emergency and normal lighting were seamlessly transparent to the lighting control system.
THE AUDITORIUM
This area consisted of a main auditorium with three satellite lecture halls. The seating in the lecture halls rotated on large turntables and could become part of the main auditorium. The main auditorium used several D8000 Entry Stations slaved to a master D8000 11-Slider Entry Station located at the back of the auditorium. Each slider was programmed to control groups of lights in different areas of the auditorium. Three of the sliders were dedicated just to lighting associated with the turntables when they were facing the auditorium. The same held true for the satellite lecture halls which had D8000 10-Button Entry Stations, each programmed for several preset lighting scenes for different areas of the lecture halls plus three buttons dedicated just to lighting associated with the turntables when they faced the lecture rooms.
The most complicated part of the auditorium house lighting was the design of the join-separate system for the turntables. The turntable seating rotated while the ceiling remained fixed. The ceiling consisted of two rings of high-power incandescent down-lights controlled as one zone along with another zone of cold-cathode accent lighting. Since the seating was sloped at a steep angle, the lighting above the lower seats had to be brighter than the lighting above the higher seats. This relationship changed depending on whether a turntable was rotated toward a lecture hall or toward the main auditorium. Each turntable also included another zone of dimmable fluorescent wall slots on both the inside and outside walls.
When facing a lecture hall, the interior ceiling down-lights, accent and wall slot lighting of a turntable had to be controllable in conjunction with the rest of the lecture hall’s lighting. Exterior wall slots and down-lights needed to be controlled by the main auditorium. Conversely, when a turntable faced the main auditorium, its interior ceiling down-lights, accent and wall slot lighting had to be controllable in conjunction with the rest of the main auditorium lighting with the exterior wall lights and down-lights turned off.
This complex arrangement was realized by breaking down the areas into room equivalents (Room 1: Auditorium; Rooms 2–4: Lecture Hall; Rooms 5–7: Interior of turntables; and Rooms 8–10: Exterior of turntables) with one simple toggle switch in each turntable routed to four contact closure inputs that were programmed to respectively join and separate the correct rooms.
THE DISTRIBUTED NETWORK
The key specification for the Minneapolis Convention Center was to provide a highly reliable global system that permitted lighting control throughout the enormous complex from any location, as well as the ability to schedule control of lighting loads locally or remotely over great distances.
To accomplish this, the 33 Meeting rooms were laid out with six RS485 twisted pair Luma-Net (Leviton’s architectural lighting control protocol to provide the high capacity signaling needed in this system) data cable runs to connect the D8000 controllers to the system. Two Luma-Net data cable runs were also included in the Exhibition Hall. Some of the data cable runs were close to 2000 feet long. The original design called for centrally installed DC power supplies for the controllers, but during commissioning it was discovered that the power supply conductors specified were insufficient for the actual pulled length. As a solution, remote DC power supplies were installed locally near the meeting room clusters to power the D8000 Controllers. The Luma-Net data runs terminated at Colortran NPC-XP Network Protocol Converters (Leviton’s flexible protocol translation interface device) that received Luma-Net control signals from the D-8000 control stations and provided DMX output to all the relays and dimmer racks. Clusters of NPCs were located in the AV closet adjacent to the meeting rooms and on the catwalk over the Exhibition Hall. Additional NPCs were used to supply six DMX universes to control DMX-converted relays from the existing section of the Convention Center. 100Mbps CAT 5 ethernet cabling was used to connect the NPCs to one another in each cluster. Finally, fiber optic cable was employed to connect all NPC clusters as well as the auditorium system and the computer running scheduling software to form one homogeneous network. The NPCs facilitated this by distributing and managing signals from Leviton NSI ColorNet™, DMX and Luma-Net™ software protocols. In addition to the NPC’s key protocol translation function, the fiber optic and ethernet cabling were essential to the success of this system. They provided highly reliable, high-speed signaling over the long distances covered in this project, eliminating the data latency problems that would have occurred with Belden 9829 cabling used in conjunction with central home run system topology alternatives.
The scheduling software was custom designed to allow easy day-to-day scheduling of the entire building’s lighting system, including over 10,000 channels of relays and dimmers. The scheduling software allowed both concurrent use at multiple locations and sequential turn on. This software was later released as a standard product called LumaScheduler.
Since the NPCs use TCP/IP to communicate Colornet protocols to each other, the installers found it very useful at commissioning time to install several 802.11B wireless access points. This made testing and programming of the system very easy to complete with minimal personnel. All of the several hundred circuits in the Exhibit Hall, for example, were completed in one evening using a wireless laptop to operate each circuit while riding around in a golf cart.
The overall network system was protected against power failure with Uninterruptible Power Supplies (UPSs) providing backup power to the NPCs. Additionally, these units store all lighting levels in non-volatile flash memory, allowing them to also entirely restore lighting levels in the event of a complete power failure.
DMX DISTRIBUTION
In addition to the architectural lighting control required in this project, one of the biggest challenges in the design phase of this system was the more than 50 “Control Receptacle Panels” (CRPs) that were specified by Schuler and Shook, each with unique requirements. Every panel had combinations of DMX 512 input and output (up to three each), connections for house lighting programmers and remote house control panels. The primary purpose of the DMX distribution system in the auditorium and exhibition halls was for operation of the moving theatrical lighting fixtures. These inputs and outputs needed to be in many different locations to allow maximum flexibility in placement of theatrical lighting and their controls. Each CRP was to be connected by ethernet to several network switches that were to be coupled together with fiber optic cable to form one network.
Leviton’s existing Ethernet DMX distribution solution was the Colortran Network Protocol Converter (NPC). It was a rack mount device that had 3 DMX inputs, 3 DMX outputs, 2 Luma-Net ports (lighting network field buses), 16 contact closure inputs, and a Handheld port. The NPC could communicate with hundreds of other NPC nodes over a TCP/IP-based protocol called “Colornet” and thus distribute DMX and the lighting control network between nodes.
The NPC became the basis for the CRP panels. A smaller version of the NPC was redesigned into two stacked printed circuit boards that fit into a standard 4-gang wall box. Custom front panels were fabricated to Schuler and Shook’s specifications and attached to the new “NPC-Wall” unit. As the operation of moving light fixtures requires a tremendous amount of network traffic, the internal processing speed of the NPCs was doubled and the ethernet was configured for 100Mbps to accommodate this. These design enhancements were retained in the standard products.
Jobsite installation of the CRP panels was done in two phases, starting with the Exhibit Hall system and then the Auditorium system, following closely behind general construction progress. The CAT-5 cable connecting the CRP’s to the network hubs was specified to be “Certified” and made installation very fast and trouble free.
Project Reviews
MICHAEL BURGOYNE (Lighting Designer at Schuler & Shook, inc.)
“While most customers are familiar with DMX systems, ethernet is the direction the industry is taking and Leviton provided the client with the greatest possibility for growth and flexibility with their distributed DMX/ethernet system. They not only met the specifications set forth, but also thought outside the box by adding capabilities that went beyond those requested. They took their Network Protocol Converter and refined it into a more economical new product to meet our CRP requirements. Their engineering people provided excellent technical documentation on everything they proposed. They not only developed new hardware solutions but also custom software solutions to solve issues as they arose on site.
They were fantastic to work with not only as far as products and software supplied but also in the way they were constantly on site to make sure that everything was done to the client’s satisfaction. In the tight time frame and compact working conditions of the overall job, by the time Leviton appeared on site to complete their work, the client had already gone through a number of inevitable problems that crop up on jobs like these. They were not only approaching the end of a long and arduous construction period, but were about to face the task of running a considerably larger facility then before. Leviton not only provided a very smooth installation, but also helped to settle down a, by then, justifiably frazzled client with constant support until they felt completely confident both about operation of the newly installed lighting system and about Leviton’s continued support under all circumstances”.
BOB WHITNEY (Head of Production Services, Minneapolis Convention Center)
“The new system put in by Leviton was a huge improvement. Let me back up a bit to explain the situation that Leviton faced. The building turnover for the completed conversion from 800,000 sq. ft. to about double that size was to have taken place on November 1st, 2001, with the first show following in April of 2002. As it turned out, construction fell behind with completion in the March/April period of 2002. With lighting installation, of necessity, following the construction phase, Leviton had a lot thrown at them to accomplish in a very short period of time. In particular, they weren’t aware of the gravity of needs the task of integrating the existing system into the new one would present. They handled the job very professionally. Leviton’s local people were great. They lived down here 7 days a week until their installation was complete”.