Arrange the following components in order they appear in a negative feedback control system
A. Error detector
B. Plant output
C. Setpoint
D. Control actuator
E. Controller
Choose the correct answer from the options given below:
Understanding Negative Feedback Control System Components
A negative feedback control system works by comparing the desired output (setpoint) with the actual system output. The difference, known as the error signal, is used by a controller to adjust the system's behavior, aiming to minimize the error and keep the output at the setpoint. This process involves several key components arranged in a specific sequence.
Ordering the Control System Components
Let's trace the flow of signals through a negative feedback control system to determine the correct order of the given components:
- Setpoint (C): This is the target value or the desired state for the system. It acts as the reference input.
- Error Detector (A): This component compares the Setpoint (C) with the measured value of the Plant Output (B). It calculates the difference between them, which is the error signal. The error ($\epsilon$) can be expressed as:
$\epsilon = \text{Setpoint} - \text{Measured Plant Output}$
- Controller (E): The controller receives the error signal from the Error Detector (A). It processes this signal and generates a command output to influence the system's behavior.
- Control Actuator (D): This component takes the command signal from the Controller (E) and converts it into a physical action. It directly manipulates the input or state of the 'plant' (the system being controlled).
- Plant Output (B): This is the actual result or response of the system (plant) after being acted upon by the Control Actuator (D). This output is then measured and fed back to the Error Detector (A), closing the feedback loop.
Component Roles in the Feedback Loop
| Component | Symbol | Function in the Sequence |
|---|---|---|
| Setpoint | C | Provides the desired value (reference). |
| Error Detector | A | Calculates the difference between Setpoint and Plant Output. |
| Controller | E | Determines the necessary control action based on the error. |
| Control Actuator | D | Implements the control action on the plant. |
| Plant Output | B | The actual system response, which is fed back. |
Final Sequence Verification
Following the signal path step-by-step:
- The desired state is defined by the Setpoint (C).
- The Error detector (A) compares the Setpoint (C) with the actual system response.
- The error signal generated by (A) is processed by the Controller (E).
- The controller's decision is acted upon by the Control actuator (D).
- The actuator influences the system, resulting in the Plant output (B), which is then fed back for comparison.
Thus, the correct sequence in which these components appear in a negative feedback control system is C, A, E, D, B.
Important Questions from Closed Loop Control Systems
Which of the following statements about the closed-loop control system compared to open-loop control system is INCORRECT?
Using negative feedback for improvements, which statement is false
Open loop transfer function of a closed loop control system is defined as:
The impulse response of the transfer function 1 is
Consider the following statements:
A. The effect of feedback is to reduce the system error.
B. Feedback increases the gain of the system is one frequency range but decreases in another.
C. Feedback can cause a system that is originally stable to become unstable.
Which of these statements are correct?
