Closed Loop Control System Block Diagram and Working Principle
There are two basic types of control systems - open-loop control systems and closed-loop control systems. An open-loop control system has only a forward path from the input to the output and there is no feedback path but a closed-loop system is the combination of an open-loop system with a feedback path from the output to the input. The closed-loop control system is also known as a feedback control system. In this article, we are going to see the Block Diagram of Closed Loop System and its working principle.
The main objective of a closed-loop system is to accept the input signal and generate the output signal by integrating the input signal and feedback signal. A closed-loop system always monitors its output signals. The closed-loop control system works with the one-time instruction or commands as the first time input, after that it uses the feedback signal as its input and works continuously until a stop command is given. For example, an automatic light on/off using an LDR circuit works in a closed-loop system. So, when darkness occurs the light will turn on automatically, and when the light is available the bulb will be turned off automatically.
Closed Loop Control System Block Diagram
Here, you can see each block of the closed-loop control system with proper terms and identification.
Input
Initially, the closed-loop control system takes the input as an open-loop control system and removes noise, and distortions. Once the system starts working, it may be or may not require the main input signal. It takes the feedback signal as the input and processes it. If a closed-loop system takes both the input signal and feedback signal then first it integrates those two signals and sends them for further processing.
The input signal can be provided by a transducer, switching device, or a programmable device.
Controlling
The controlling part of the closed-loop system integrates the both input and output signal and it decides which part of the signal is to be allowed for processing and which part of the signal is to be rejected. The controller controls the process flow, speed, integration, etc. It involves so many integrated operations, calculations, and functions.
Feedback Element
A closed-loop control system has one or multiple feedback paths. The feedback element is that which takes the output signal of the system as its input and generates the feedback signal as its output. The feedback element may be a transducer or sensor. For example, limit switches and thermostats can be the feedback element of a closed-loop control system. In an automatic heating system, the thermostat continuously measures the operating temperature, once the temperature exceeds the preset limit, it will generate a feedback signal and be fed to the control system to turn off the heater.
How does a Closed Loop Control System Works?
The basic working principle of a closed-loop system is that it takes the main input signal as the starting instruction and once it starts working, it continuously takes the feedback signal as its input and works without any interruption until the stop command is given to the system. A closed-loop system can work even when the main input signal is removed. A closed-loop control system is a continuous process until we want to stop forcefully.
Read Also:
Closed Loop Control System Block Diagram and Working Principle
Reviewed by Author
on
November 07, 2021
Rating:
Reviewed by Author
on
November 07, 2021
Rating: