Which of the following statements are true? for the false statements, explain why you think they are false:
(a) feedforward and feedback control require a measured variable.
(b) for feedforward control, the measured variable is the vari able to be controlled.
(c) feedback control theoretically can provide perfect control (i. e., no deviations from set point) if the process model used to design the control system is perfect.
(d) feedback control takes corrective action for all types of process disturbances, both known and unknown.
(e) feedback control is superior to feedforward control.

Options: (a) and (d)

Explanation:

Measured variable is required for feedback and feed forward as the corrective measures taken by the controller are based on the measured variable as the without the measured variable there won't be any error.

Since, error is the difference between the measured variable and a set standard.

In the feedback control mechanism, evaluation of error is done and then corrective measures are taken according to the error evaluated no matter known or unknown.

Thus option (a) and (d) are correct.

the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true?

a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of

5

9

degree celsius.

a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit.

a temperature increase of

5

9

degree fahrenheit is equivalent to a temperature increase of 1 degree celsius.

a) i only

b) ii only

c) iii only

d) i and ii only