the gas line provides feedback to the micro controller thus adjusting the pwm proportional valve to the set point closed loop this closed loop system with a full pid control algorithm and controlled by the micro controller allows the gas pressure to be controlled via a voltage or current profile thus creating an infinite number of pressure versus time settings an on board rs232 interface unit 43 allows the capability to capture the information from the gas pressure transducer before the gas enters the mold 45 and thus be used as a monitoring and statistical tool a pc may display a menu system where pressure can be profiled either up or down as a geometric function a digital display panel 50 shown in fig9 b shows the pressure set point and the actual value during cycle the micro controller pwm is driven using a separate 0 24 vdc 4 0 amps max rated regulated power supply 57 as shown in fig9 a ports for the pressure sensor 55 and rs232 54 allow for data acquisition valve control signals 56 allow voltage input into the controller board using the up down keys 61 and 62 shown in fig9 b the pressure settings are easily adjusted within a pressure sensitivity scale of u00b1 1 psi and can be seen on screen 68 as setpoint vs actual adjustments to the software are made using diagnostics.