Nowadays, the application of PLC has been widely known, and the application of PLC in this digital world is obviously applied in the industrial field. Generally, PLCs used in the industrial field usually control the mechanical movement of machines or heavy machines to achieve efficient production and precise signal processing. In this project, discussions about PLC applications will be explained and specified in more detail. Therefore, the machine used to prepare the automatic filling water into the bottle is completely controlled by the PLC , which serves as the core of the system. The system running sequence is designed by ladder diagram, and this project uses CX-Programmer software to program. In this system, the sensor usually plays an important role as the input signal transmitter of the PLC. In this project, the sensor is used to detect the position of the bottle moving at a low speed along the conveyor belt while the machine is running.The input signal sent from the sensor to the PLC has been usedas a reference. The signal can be determined according to the user's requirements and the output signal that is completely consistent with the PLC programming language. In addition, electronic and electrical equipment usually controlled by PLC such as motors, pumps, sensors, conveyor belts, buzzers and other equipment.
