Closed-loop control

Definition

Closed-loop control is a control system that uses feedback to compare the actual output with the desired output and make adjustments as necessary to achieve the desired performance. This process continuously monitors system outputs, making corrections based on differences between actual and target values, leading to improved accuracy and stability in the system's operation.

5 Must Know Facts For Your Next Test

1. Closed-loop control systems can automatically adjust their operations to maintain stability, even when external conditions change.
2. These systems typically include sensors to measure the actual output, which helps in calculating the error between the desired and actual values.
3. An example of closed-loop control is a thermostat regulating room temperature by turning the heating or cooling system on and off based on temperature readings.
4. Compared to open-loop systems, closed-loop control offers enhanced accuracy and reliability by correcting errors in real-time.
5. Common applications of closed-loop control can be found in industries such as chemical processing, robotics, and aerospace engineering.

Review Questions

• How does feedback function within a closed-loop control system, and why is it essential?
  • Feedback in a closed-loop control system involves continuously measuring the actual output and comparing it with the desired output. This comparison helps identify any discrepancies, allowing the system to make necessary adjustments to minimize errors. Without feedback, the system would lack the ability to correct itself, leading to potential instability and poor performance.
• Discuss the advantages of closed-loop control systems over open-loop systems in industrial applications.
  • Closed-loop control systems offer several advantages over open-loop systems, primarily due to their ability to adjust based on real-time feedback. This adaptability results in improved accuracy, stability, and response time to changes in external conditions. While open-loop systems operate without feedback and cannot correct errors, closed-loop systems can maintain optimal performance even in fluctuating environments, making them preferable for complex industrial processes.
• Evaluate how closed-loop control contributes to efficiency and safety in chemical engineering processes.
  • Closed-loop control significantly enhances both efficiency and safety in chemical engineering processes by enabling real-time monitoring and adjustments based on feedback. For instance, in a reactor where temperature or pressure must be tightly controlled, a closed-loop system ensures that any deviations from set points trigger immediate corrective actions. This not only optimizes resource use and reduces waste but also mitigates risks associated with unsafe operating conditions, ultimately leading to more reliable and sustainable industrial operations.

Related terms

Feedback: Feedback is the process of taking a portion of the output of a system and returning it to the input to adjust the system's performance.

Control System: A control system is a device or set of devices that manages, commands, directs, or regulates the behavior of other devices or systems using control loops.

Set Point: The set point is the desired value or target that a control system aims to achieve and maintain through its operations.