Development of an electromechanical positioner with PID controller embedded in a PIC18F4550 microcontroller: A practical validation case study

摘要

This work presents the prototype development of a valve positioner with PID controller, embedded in a PIC18F4550 microcontroller, manufactured by Microchip, which is configured and supervised by a PC station. For performance validation, the system was applied to a level control loop in SMAR didactic plant with 4-20 mA communication protocol. The positioner consists of a direct current motor used to control the position of a ball valve. The system identification was obtained from the open loop response curve, where the chosen controller tunings were Ziegler-Nichols and Haalman (both from classical control techniques). The results were appreciable in both tunings responses. The audit of control loops was implemented using performance indices IAE, ITAE, ISE, EITI, which Ziegler-Nichols tuning proved itself more advantageous in this situation.