Method and a system for operating a controllable multi-variable process

A method for operating a controllable multi-variable process, comprising the steps of:

• providing a multi-dimensional display representation of a multiplicity of variables according to individual coordinate axes, said multiplicity of variables comprising both process-variables and quality-variables of the process;
• accumulating sets of values of the process-variables and quality-variables from previous multiple operations of said controllable multi-variable process, the sets of values being accumulated as individual datapoints of a historical record;
• representing current values of the process-variables and quality-variables on respective axes of the coordinate axes of the multi-dimensional display representation, the current values being represented on the coordinate axes in relation to a first operational envelope which defines bounds for the values of the individual process variables, the first operational envelope being derived from datapoints selected from the datapoints of the historical record;
• storing the selected datapoints as stored datapoints;
• deriving a second envelope from a subset of the stored datapoints;
• and
• representing the second envelope in the display representation as an inner envelope to the first envelope;
• and wherein control of said controllable multi-variable process includes effecting change in value of at least one of the process variables to bring about change as between the definition of the inner envelope and the current value of a process variable indicated against the inner envelope in the display representation.