Patent ID: 7555405

Claim:
A method for creating a CUSUM chart permitting a mathematical determination of when a step change in an industrial process has occurred, comprising the steps of: identifying time slices for select industrial process filter criteria known to be true; determining using a microprocessor said time slices that fall within a time window of a trial period of the industrial process being analyzed; determining using said microprocessor said time slices that meet the filter criteria, said time slices meeting the filter criteria defining a trial block; creating a plurality of slice blocks that is equal to a plurality of said time slices that met the filter criteria of the industrial process, so that said trial block is comprised of a number slice blocks equal to said plurality of time slices; grouping all observed time slices not running under the filter criteria during the trial period into said slice blocks of said trial block so created; ranking measured data during said trial period against data observed that are in said time slices not running under the filter criteria during said trial period; and, creating a CUSUM chart for determining when a step change in the industrial process has occurred.