Lesson 6 System Terminology and Concepts

What is a control system?

• A type of feedback mechanism

• An arrangement of subsystems and processes

• A single entity that operates independently

• A method of data collection

Answer explanation

A control system is best described as an arrangement of subsystems and processes that work together to manage and regulate behavior, making the correct choice the one that highlights this interconnected structure.

Which type of control system uses feedback?

• Hybrid Control

• Closed-Loop Control

• Open-Loop Control

• Feedforward Control

Answer explanation

Closed-Loop Control systems utilize feedback to compare the actual output with the desired output, allowing for adjustments to be made. This is in contrast to Open-Loop Control, which does not use feedback.

What does positive feedback do?

• Reduces error

• Amplifies error

• Prevents error

• Maintains stability

Answer explanation

Positive feedback amplifies error by increasing the deviation from a set point, leading to greater instability. This contrasts with negative feedback, which reduces error and maintains stability.

Which of the following is an example of negative feedback?

• A microwave oven running for a set time

• An air conditioner adjusting based on room temperature

• A traffic light adjusting based on expected flow

• A microphone causing screeching noise

Answer explanation

An air conditioner adjusting based on room temperature is an example of negative feedback, as it responds to changes in temperature by activating or deactivating to maintain a stable environment.

What is dead time in a process?

• The time taken to reach steady-state

• The time taken for input to change

• The delay before the system starts responding

• The time taken for feedback to be processed

Answer explanation

Dead time refers to the delay before the system starts responding to an input change. This is crucial in process control as it affects the system's performance and stability.

What does the time constant indicate?

• The speed of the system's response

• The overall gain of the system

• The amount of energy stored in the system

• The delay before the system starts responding

Answer explanation

The time constant indicates how quickly a system responds to changes. A smaller time constant means a faster response, while a larger one indicates a slower response. Thus, it reflects the speed of the system's response.

Which type of control is proactive?

• Closed-Loop Control

• Feedforward Control

• Positive Feedback

• Negative Feedback

Answer explanation

Feedforward Control is proactive as it anticipates changes and adjusts inputs accordingly, unlike Closed-Loop, Positive Feedback, and Negative Feedback, which react to changes after they occur.

What is the effect of a higher resistance in a system?

• Decreased dead time

• Increased stability

• Slower response time

• Faster response time

Answer explanation

Higher resistance in a system leads to increased opposition to current flow, resulting in a slower response time. This is because the system takes longer to react to changes due to the added resistance.

What characterizes an underdamped system?

• Slow response with overshoot

• Oscillates before settling

• Fastest response without overshoot

• No overshoot

Answer explanation

An underdamped system is characterized by oscillations before settling to its final value. This means it will exhibit a response that overshoots the target before stabilizing, making 'oscillates before settling' the correct choice.

What does process gain determine?

• The stability of the system

• The type of feedback used

• The delay before response

• The change in output due to input change

Answer explanation

Process gain refers to the change in output due to an input change. It measures how effectively a system converts input into output, making 'The change in output due to input change' the correct choice.