A method and apparatus is provided for identifying a cause of a fault based on controller output. The method comprises processing at least one workpiece under a direction of the controller and detecting a fault associated with the processing of the at least one workpiece. The method further includes...http://www.google.se/patents/US6778873?utm_source=gb-gplus-sharePatent US6778873 - Identifying a cause of a fault based on a process controller output
