The method used to tune controllers with the help of process reaction curve is Open loop methodThe process reaction curve method involves creating a process reaction curve resulting from a disturbance, which is then utilized to determine the controller gain, integral time, and derivative time. This approach is conducted in an open loop system to enable the separation of process response without any control action taking place.The process is allowed to attain a state of stability or as near to it as feasible. Following that, a minor step disturbance is introduced while the system is in open loop mode, with no control intervention, and the response of the process variable is monitored and recorded.