Figure 14 Flowchart of the controller algorithm. u is the control-signal and y is the controlled variable. Î”u and Î”t are represented by du respectively dy in the figure. The chosen algorithm had some interesting properties worth noticing. First of all, it made a minimum of assumptions about the process. Basically, the only assumption made was that the controlled variable had a maximum for some control-signal and that no local extremum points existed. Secondly, the algorithm did not depend on any absolute value of the controlled variable, it only depended on the variation.