The servo motor has a gain of 4 rpm V and a time constant of 1 0 seconds. The speed sensor changes its output linearly from 0 - 6 V for a speed change of 0 - 8 0 rpm . The controller is of PI mode with 0 - 1 0 V output and 5 0 % PB . The constant of integration is 5 ( % min ) % . Output of the controller goes through an amplifier of gain 2 to drive the motor. Set point is 4 5 rpm . Draw the process control loop and find natural frequency of the closed - loop system.