Difference between Open Loop & Closed Loop Control System

The behavior of the system can be determined with the help of a differential equation is known as the control system. So it controls different devices as well as systems with the help of control loops. Control systems are classified into two types like open loop and closed loop. The main difference between open-loop and closed-loop control system is, the required output within the open loop doesn’t depend on the controlled act whereas, in closed-loop, the required output mainly depends on the controlled act. This article discusses an overview of the difference between open-loop and closed-loop control systems.

What is an Open Loop Control System?

In this kind of control system, the output doesn’t change the action of the control system otherwise; the working of the system which depends on time is also called the open-loop control system. It doesn’t have any feedback. It is very simple, needs low maintenance, quick operation, and cost-effective. The accuracy of this system is low and less dependable. The example of the open-loop type is shown below. The main advantages of the open-loop control system are easy, needs less protection; operation of this system is fast & inexpensive and the disadvantages are, it is reliable and has less accuracy.


Open Loop Control System
Open Loop Control System

Example

The clothes dryer is one of the examples of the open-loop control system. In this, the control action can be done physically through the operator. Based on the clothing’s wetness, the operator will fix the timer to 30 minutes. So after that, the timer will discontinue even after the machine clothes are wet.
The dryer in the machine will stop functioning even if the preferred output is not attained. This displays that the control system doesn’t feedback. In this system, the controller of the system is the timer.

What is a Closed-Loop Control System?

The closed-loop control system can be defined as the output of the system that depends on the input of the system. This control system has one or more feedback loops among its input & output. This system provides the required output by evaluating its input. This kind of system produces the error signal and it is the main disparity between the output and input of the system.

Closed Loop Control System
Closed-Loop Control System

The main advantages of the closed-loop control system are accurate, expensive, reliable, and requires high maintenance.

Example

The best example of the closed-loop control system is AC or air conditioner. The AC controls the temperature by evaluating it with the nearby temperature. The evaluation of temperature can be done through the thermostat. Once the air conditioner gives the error signal is the main difference between the room and the surrounding temperature. So the thermostat will control the compressor.
These systems are accurate, expensive, reliable, and requires high maintenance.

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Difference between Open Loop and Closed Loop Control System

The main difference between open-loop and closed-loop control system mainly includes its definition, components, construction, reliability, accuracy, stability, optimization, response, calibration, linearity, disturbance of the system and its examples

Open Loop Control SystemClosed-Loop Control System
In this system, the controlled action is free from the outputIn this system, the output mainly depends on the controlled act of the system.
This control system is also called a Non feedback control systemThis type of control system is also called a feedback control system
The components of this system include a controlled process and controller.The components of this kind of system include an amplifier, controlled process, controller and feedback
The construction of this system is simpleThe construction of this system is complex
The consistency is non-reliableThe consistency is reliable
The accuracy of this system mainly depends on the calibrationThese are accurate due to feedback
The stability of these systems are stableThe stability of these systems are less stable
The optimization in this system is not possibleThe optimization in this system is  possible
The response is fastThe response is slow
The calibration of this system is difficultThe calibration of this system is easy
The disturbance of this system will be affectedThe disturbance of this system will  not be affected
These systems are non-linearThese systems are linear
The best examples of this control system are automatic washing machine, traffic light, TV remote, immersion rod,  etc.Examples of this kind of control system are AC, control systems for temperature, pressure and speed, toaster, and refrigerator.

Thus, this is all about an overview of the difference between the open-loop control system and the closed-loop control system. These are two kinds of control systems. The open-loop type system mainly depends on the input and its construction is simple whereas the closed-loop type system is difficult to design and the output of this system mainly depends on the input. Here is a question for you, what are the applications of open-loop and closed-loop control systems?

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