DIFFERENT APPLICATIONS OF PROGRAMMABLE LOGIC CONTROLLER (PLC)

Early Programming Logic Control (PLC) were designed to replace relay logic systems. These PLCs were programmed in “Ladder Logic”, which strongly resembles a schematic diagram of relay logic. Programming logic control has several features like protection from the open area conditions such dust, heat and cold. PLC also has the ability to arrangement the inputs/outputs.It has low cost compared with microcontroller systems becaus e using PLC in different applications only required to change the software for each application but in case of using microcontroller the hardware components itself must be changed with different applications. Two important applications for programming log ic control and also an engineering solution to save the human life are explained in this paper, one application is a robot used as a toxic chemical substances spraying, and the other application is a robot used for washing the faces glasses of skyscrapers. These mobile robots used PLC as a controlled tool for its motion and liquid flow rate also.