CPAT Process Control Systems & Automation

Question 1

What does the acronym PID stand for in a PID controller used in process automation?

Accepted Answer

Proportional-Integral-Derivative

Answer

Process-Input-Data

Answer

Proportional-Inlet-Discharge

Answer

Pressure-Integral-Differential

Question 2

In a feedback control loop, what signal does the controller compare to the setpoint to determine corrective action?

Accepted Answer

The process variable (PV)

Answer

The manipulated variable

Answer

The controller output

Answer

The disturbance variable

Question 3

Which control action in a PID controller is responsible for eliminating steady-state offset (residual error)?

Accepted Answer

Integral action

Answer

Proportional action

Answer

Derivative action

Answer

Feed-forward action

Question 4

What is the primary purpose of derivative action in a PID controller?

Accepted Answer

Respond to the rate of change of the error to dampen oscillations

Answer

Eliminate offset by integrating past errors

Answer

Set the baseline controller output

Answer

Amplify the proportional response to large errors

Question 5

In a simple process control loop, what is the role of the final control element?

Accepted Answer

Receive the controller output and physically alter the process

Answer

Measure the process variable

Answer

Transmit the process signal to the controller

Answer

Compare the setpoint to the measured value

Question 6

What is 'cascade control' in process automation?

Accepted Answer

A control strategy where two controllers are connected, with the output of the primary controller setting the setpoint of the secondary controller

Answer

A control strategy that uses feedforward signals to anticipate disturbances

Answer

A fail-safe shutdown sequence triggered by high process values

Answer

A method of tuning a PID controller using relay feedback

Question 7

Which of the following best describes a 'process variable' (PV) in a control loop?

Accepted Answer

The measured value of the parameter being controlled

Answer

The desired operating value entered by the operator

Answer

The output signal sent from the controller to the final control element

Answer

The difference between the setpoint and the measured value