Hypervelocity wind tunnel 9 control system

The US Naval Surface Warfare Center Hypervelocity Wind Tunnel 9 operates from Mach 8 to Mach 14 with Reynolds numbers ranging from 75,000 per foot to 53,000,000 per foot. The Tunnel 9 facility control system was recently modernized. The architecture of the original and upgraded control system is described. In the upgraded system programmable logic controllers provide safety interlocking and input/output interfacing to the facility valve system. Mini computers (MicroVax II) provide an operator interface to the logic controllers, the sensors, the prerun initialization and online tunnel run command and status monitors, the displays, and tunnel condition data acquisition.<>