Abstract: A system having a processor-based process control system for a plastic injection molding machine performing a plastic injection molding process having an I/O bus network containing a plurality of I/O modules operably connected to a corresponding I/O device associated with the plastic injection molding machine and a first computer having and I/O bus controller directly connected to the I/O bus network, a real-time operating system, and a first processor executing a plastic injection molding control program for controlling the plastic injection molding process.

Abstract: A process for determining the precise initial volume of the mold cavity of an injection molding machine in which a first and second section engage into seated alignment thereby forming a mold cavity. Vent valves, controlling communication between the interior and exterior of the mold cavity, are closed thereby sealing the mold cavity. An injection means begins injecting a test substance into the mold cavity. The test substance continues filling the mold cavity until the detection of a predetermined threshold level. A measuring means performs the step of measuring the amount of the test substance in the mold cavity, thereby providing sufficient information for calculating the precise initial volume of the mold cavity of the injection molding machine. The apparatus used to perform the method described herein comprises an injection molding machine with a mold cavity configured with vent valves capable of sealing the interior of the mold cavity from the exterior.