Abstract: A method for determining a root cause for a drift in a process or a machine, the function of which is determined by a model describing a relationship between setup and/or input variables and output property or properties, comprising the steps of: (a) Assigning desired output properties for a product of said machine or process, and allowed ranges for said properties; (b) Assigning original values to said variables for obtaining by said machine or process said assigned output properties within said assigned ranges; (c) Measuring the various output properties of the machine or process; (d) When measuring an output property of the machine or process that drifts from its assigned value, substituting the one or more measured output properties in their corresponding model equations, and calculating for each variable in each equation its presumed value, assuming it is the sole cause of the drift; and (e) Analyzing all presumed calculated variable values and the measured values of the output properties of the machine

Abstract: A controller and method for efficient tracking and optimizing of a machine set-point, to correct for changes in machine characteristics, can include: (a) defining allowed ranges for output product properties and possible machine set-points, and optimal set-point criteria; (b) finding updated constants for the machine model by calibrating the model; (c) using the updated constants to find all set-points providing a product with properties within the allowed ranges; (d) determining an optimized set-point; (e) operating the machine at the optimized set-point, and obtaining a new output product; (f) comparing the properties of the new output product to the allowed ranges; (g) successfully finishing the procedure as finding a new set point if the properties of the output product are within allowed ranges; and, (h) if the properties of the output product are out of said allowed ranges, repeating the procedure from b.