3. The experimental process reaction curve of the concentration control of the effiuent with a PiD controller is shown in the figure. The step change of the manipulated input was increased from 50% to 60%. a) Using the data from the graph, approximate the open-loop response of a first order plus dead time system. (i.e. find the values of K=output (at the steadyyinputlat the steady), s=output (at the steady)slope at the point of inflection and temtime elapsed unbil the system responded). b) Select the controller settings using the Cohen-Coon technique