Control Systems

Basics

Other Topics

OPEN LOOP SYSTEM

Classification of Control system:

Based on whether the control system controls itself in real-time or not, we can classify our control system into

  • Open-loop system
  • Closed-loop system

Open-loop system:

A fan with a regulator

Assume, you have set your fan regulator switch to number $5$. Now, during midnight, there has been a heavy rainfall. 

Will your fan reduce speed on its own??

NO

There has been a low power supply during peak hours. 

Will your fan regulate its speed on its own??

NO

Open-loop system is a control system, which never changes the result on its own. 

  • There is no provision to measure the output.
  • There is no provision to feed back the measured output to the input.
  • There is no provision to alter the input in order to correct the error in the results.
  • Whenever desired result got changed, a human intervention is needed to correct it.
 
Hence we can say, In an open loop control system, due to some internal or external factors, output may change from desired value in an uncontrolled manner.

No feedback arrangement

Advantages:

  • Simple and cost-effective.
    • No output measurement, No feedback, No error control mechanism.

Disdvantages:

  • Inaccurate and unreliable.
    • No provision to measure or control the output.
  • Traffic light control
  • Washing Machine
  • Fan