2. In a "bang-bang" controller (one that turns the actuator fully on or fully off), reducing the size of the dead band...

1. increases chatter
2. decreases chatter
3. will cause the system to become marginally stable
4. will cause the system become unstable
5. increases the system observability

3. A proportional controller is one in which

1. the response is directly proportional to the error.
2. the response is inversely proportional to the error.
3. one in which the integral term dominates the derivative term.
4. one is which the derivative term dominates the integral term.
5. the response is proportional to the integral of the error.

4. The reason that error cannot be completely eliminated in a proportional controller is

1. to keep that error at zero requires a residual error.
2. a zero error leads to marginal instability.
3. this would be an open loop system.
4. there are no derivative terms.
5. this would lead to unacceptable chatter

6. Unlike the proportional controller, a purely integral controller

1. can reduce the residual error to zero.
2. has superior transient response
3. is much more responsive
4. cannot respond to negative residual error.
5. anticipates the error

7. A purely integral controller will react to a unity error signal by

1. ramping the output.
2. stepping the output proportionally to the error.
3. giving no response.
4. a sinusoid output signal.
5. stepping the output equal to the negative of the error

8. A proportional / integral controller...

1. retains the transitive response advantages of the proportional controller and the residual error advantages of the integral controller.
2. retains the transitive response advantages of the integral controller and the residual error advantages of the proportional controller.
3. retains the transitive response advantages of both the proportional and integral controllers.
4. retains the residual error response advantages of both the integral and proportional controllers.
5. anticipates like the derivative controller but does not have good residual error response.

9. The derivative controller provides a system with

1. an enhanced response to sudden changes in residual error.
2. is best for systems with small inertia.
3. output inversely proportional to the rate of change in the error.
4. better response to the average of the most recent error.
5. responds to the accumulated error

10. By implementing a PID controller as a parallel circuit one might introduce the phenomenon of derivative overrun in which the controller exhibits significant overshoot in response to a set-point change . A solution to this problem is to

1. allow the derivative to operate on the control variable rather than the error.
2. increase the gain of the derivative term significantly.
3. increase the gain of the integral term significantly.
4. decrease the proportional gain.
5. decrease the integral term significantly.

11. Designing a PID controller to have both manual and automatic modes for tuning purposes requires so-called bumpless transfer to not introduce spurious transients when the mode is changed.

1. It is possible to eliminate this problem with a minor circuit enhancement.
2. This must be done by precisely matching the manual and automatic voltages.
3. Can only be handled by digital circuitry.
4. This is something that must be lived with.
5. This cannot be done on line.

12. Effective use of the integral part of a PID controller in a slow process requires that

1. the integral gain be set high and the proportional gain be set low.
2. the integral gain be set low and the proportional gain be set high.
3. the derivative gain be set low and the proportional gain be set low.
4. the derivative gain be set low and the proportional gain be set high.
5. a simple proportional control

• 13. Implementing a feedforward controller
• is straight forward using a microprocessor because of the transport delay.
• is easiest done using analog circuitry because of the transport delay.
• can be handled effectively ignoring the transport delay of the feedforward loop.
• eliminates the need for the feedback loop in most systems.
• is impossible to implement because of the transport delay.

14. Feed forward is used in closed loop control systems to provide anticipatory output changes to compensate for large input command changes. Use of a feed forward signal will generally...

1. improve system performance.
2. reduce the cost of system hardware.
3. reduce the performance of the feedback path.
4. compensate for wide variations in system gains caused by temperature changes.
5. reduce system component requirements, thus improving system reliability.

Page Revised: July 14, 2003