Answer:
PLC is used in Industries, manufacturing Plant and help to improve the control over Mechanical & Electrical devices.
It helps in following ways :
1.) Automation : Using PLC a process can be switch to 100% automatic, previously it was done by relay logic, which was more complicated in terms of hard wiring
2.) Fast & Reliable : Makes the process fast and reliable even after so many repeated cycles.
3.) Data Archive : Helps to log data of process in terms of graph etc.
4.) Communicate & Calculation : It can calculate the data and communicate via web .