A pneumatic function generator system for maintaining a desired pressure and/or a desired rate of pressure change with respect to time. The pneumatic function generator system may include a servo valve for controlling the amount of fluid traveling therethrough, a primary sensor for measuring the pressure of the fluid and for generating an analog signal corresponding to the pressure of the fluid, an analog-to-digital module for converting the analog signal to a digital value, and a digital device for receiving the digital value and, depending on the digital value, generating a control signal that is used to control the opening and closing of the servo valve.