Microcomputer-Controlled Precision Pneumatic Pressure Generator

An increasing variety of avionics require precision pneumatic pressure stimuli during organization and intermediate maintenance. The accuracy and long-term stability requirements approach the best mercurial standards. Pressure stimuli must be coordinated and varied at precise rates that are beyond the frequency response of mercury columns and many electromechanical sensors. Test systems are frequently required to simultaneously monitor and evaluate unit under test (UUT) response and generate pneumatic stimuli. In addition, the environment is frequently hostile, maintainability is paramount, performance must always be known and warmup time must be nil. Comprehensive trade studies, tests, and analyses were performed. This initial work indicated a new pressure generator should be a "smart" instrument and should use a pressure sensor not a density sensor. Current field and production experience indicates performance objectives have been exceeded and this new type of precision pressure generator can be readily incorporated in a variety of test systems or be used "stand-alone". This paper discusses the design implementation, features, and characteristics of this microcomputer controlled precision pneumatic pressure generator-a new "smart" test instrument.