PLC's are devices that are used to control and automate industrial and commercial processes. They are used in a variety of applications such as factory automation, process control, and packaging. 

It is an industrial computer control system that monitors continuously the state of input devices and takes decision in order to control the status of output devices.There are two types of PLC's: fixed PLC and modular PLC. 

How a PLC works:  

1) Input Monitoring - It can be used to monitor and control the operation of a machine.

2) Logic Programming - These can be programmed to perform a variety of tasks. PLC's can also be programmed to control the flow of information.

3) Status of Output Control - It updates the output according to use logic


PLC's are extremely versatile than dedicated hardware controllers

These are modular, which allows them to be easily expanded or reconfigured

Easy trouble shooting

They have a faster response time

PLC's are less expensive