The objective of this work is to design Proportional Integral Derivative controller using PLC and implement it to control the speed of a DC motor. The modifications of control system have to be done frequently. In order to do so we have to come across lots of complexities. These PLC based systems removes the detailed hardware design considerations. Now PLC offers us an easy technique to modify the wiring of control system without changing its hardware. The speed of a DC motor is controlled here by varying the armature voltage using PLC as discrete state controller. Thus by applying an appropriate ladder logic a PID controller is developed as it has the combined advantages of proportional, integral & derivative control action. Here soft start method is implemented to start the motor safely without any external starter. In this controller the set point can be changed during run time. So, it is not required to off the controller to set new set point speed. This increases the flexibility of the controller. The detail ladder logic, hardware components and circuit required to perform this work is discussed in this book.
