Parameter Evaluation of Three-Point Step Control System

The three-point controller is one of the simplest controllers used in industry. Most environments with programmable logic controllers and distributed control systems allow such blocks in their design. The three-point controller consists of three switching states, i.e., one input and two outputs, depending on the input signal's positive or negative deviation from the desired value. It allows for an upper and lower limit of deviation where no switching takes place. The three-point step control system extends the step controller with a corrective feedback loop. This paper presents the implementation and parameter evaluation of the three-point step control system. Based on theoretical analysis and simulations, general comments are made on the impact of the controller parameters on the control system's performance. Finally, recommendations for tuning the three-point step controller are formulated.