Reliant Park Stadium scores with GE-controlled retractable roof

Houston, TX - When the National Football League's newest team, the Houston Texans, kicked off at Reliant Park earlier this fall, they began playing in the world's first retractable-roof NFL stadium.

By Control Engineering Staff December 23, 2002

Houston, TX – When the National Football League’s newest team, the Houston Texans, kicked off at Reliant Park earlier this fall, they began playing in the world’s first retractable-roof NFL stadium. The fully automated, two million-pound retractable roof-which was designed, manufactured and installed by Minneapolis, MN-based integrator Uni-Systems-features an automation system from GE Fanuc Automation , an affiliate of GE Industrial Systems. With safety and reliability as key design priorities, the new roof will operate an estimated 120 times each year for the next 30 years-keeping fans and players comfortable through every game.

According to Lennart Nielsen, senior electrical engineer at Uni-Systems, precision control in sports venues is essential. ”When an announcer tells a stadium full of people that it’s time for the roof to roll, it had better roll on time, every time, not only for show purposes but for safety reasons,” Nielsen says.

The bi-parting retractable roof consists of two large panels that open at the 50-yard line, then ride along steel rails at 35 feet per minute under ideal wind conditions, reaching each end zone about seven minutes later. Ten tri-chord trusses with a carrier at each end support the roof panels. Each carrier has two wheels that ride on a 960-foot rail supported by two massive super-trusses running parallel to the field.

The control system features GE Fanuc Series 90-70 programmable logic controller (PLC), which determines travel speed based on data collected from wind sensors and controls the 20 GE AF-300 G11 adjustable frequency drives that move the wheels on the carriers. Data are transmitted via fiber optics running up to each roof section, where the signals are converted to microwave.

GE Fanuc Cimplicity HMI Plant Edition software collects data and provides the stadium operator with a graphical representation of the roof transport system on a standard PC. The operator can double click on any panel, and it expands to fill the screen. The panel door then swings open to graphically show all of the components. By clicking on a drive, operators can step through all of the parameters, just like physically touching the buttons on the front of the drive. Live cameras feed images from four roof locations into the central control room.

Control Engineering Daily News DeskGary A. Mintchell, senior editor