REUSE OF MANUFACTURING PROCESS DESIGN MODELS AS PART OF A DIAGNOSTIC SYSTEM

A method and apparatus that includes determining differences between a process model and an actual process are used as a diagnostic system for the actual process. The process model includes elements from a design process to provide a “known good” condition for evaluating the differences. Initial input states to the process model are the initial input states to the actual process. Output information correlated to states in the actual process is provided by controls, such as programmable logic controllers, that manage the actual process.