EXPLAIN THE CONCEPT OF CLOSED LOOP SYSTEMS AND CLOSED LOOP CONTROL
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Closed-loop Systems • There are certain systems where the input of the control process cannot be controlled by the output quantity and such system are called open-loop control systems and the open-ended non feedback systems are called open loop systems.
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• For measuring, monitoring and controlling a process, the electrical or electronic control system is used. By monitoring the output control the process can be controlled in a precise way and for reducing the error and checking the desired output the actual output is sent back as feedback. • The feedback signal is the quantity of output is measured and the closedloop system is used for controlling and adjusting itself with respect to the feedback signal.
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Closed loop control • For instance, if you consider a closed loop system for washing and drying clothes then there is a sensor that would observe the actual dryness of the clothes and then check it out with the input reference. The controller amplifies the error signal and the required correction is made by the controller output to the heating system for reducing any error. The controller may increase the temperature or dry time if the clothes are wet and if the clothes are nearly dry the temperature is decreased or the process is stopped for avoiding overheating of clothes.
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• The feedback signal is used for characterizing the configuration of a closed loop which is received from the clothes drying system. The difference between the required dryness and actual dryness of the clothes is related directly to the magnitude and polarity of the resulting error signal. • All the disturbances and changes in the systems can be handled effectively because of the closed-loop system and its sensor thereby it reduces the error in completing the desired task.
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• For instance, if the heat is lost after the dryer door is opened, then the temperature changes are noted by the feedback sensor and it is auto corrected and a constant temperature is maintained. • The error signal is the difference between the input signal and the feedback signal and it is fed back to bring the output to the desired value and in this example when the error signal is zero then the clothes are completely dry.
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• In a closed loop control system, the feedback path relies on the output accuracy which is actually or made accurate and inside the electronic control systems and circuits, the most preferred system used is the feedback control rather than an open looped system. • There are lots of advantages of closed systems over open loop systems. The main benefit is to decrease a system’s sensitivity to external disturbances
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The
main characteristics of the Closed loop control can be defined as:
• To enhance the stability of an unstable system • Reliable and consistent performance is produced • Sensitivity of the system can be increased or decreased • Robustness is enhanced to the process. • Errors are reduced automatically by handling system input.
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As said earlier a good conditioned closed system can have various advantages over an open loop system. The major drawback is that it should have more than one feedback circuit. If it is more sensitive with respect to change or oscillates in efficiency due to too much of auto-correction for seeking perfection then the system would collapse finally. For more information join the institute of electrical training to make your career in this field.
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