Process Control Exam 3 || || || ||
Questions With Answers || ||
What is the characteristic equation of a feedback loop
|| || || || || || || || ||
and what is its significance? - CORRECT
|| || || || || || ||
ANSWER(S)✔✔The characteristic equation is the || || || || ||
denominator of the transfer function. The roots of this || || || || || || || || ||
equation are known as poles and determine the dynamic
|| || || || || || || || ||
behavior of the process. If the poles are real and || || || || || || || || || ||
negative, the dynamic behavior is overdamped. If the || || || || || || || ||
poles are complex, the dynamic behavior is oscillatory. If
|| || || || || || || || ||
the poles are real and positive, the dynamic behavior is
|| || || || || || || || || ||
unstable.
What do the transfer function for the closed-loop
|| || || || || || || ||
response indicate about the dynamics of feedback || || || || || || ||
systems for setpoint changes and disturbance rejection?
|| || || || || ||
- CORRECT ANSWER(S)✔✔A closed loop transfer
|| || || || || || ||
function means that the poles will be the same for
|| || || || || || || || || ||
setpoint changes and disturbances. For example, if a
|| || || || || || || ||
linear process has overdamped closed loop behavior for
|| || || || || || || ||
setpoint changes, it will also have overdamped closed
|| || || || || || || ||
loop behavior for disturbance upsets. However, if a
|| || || || || || || ||
positive zero is added with the disturbance rejection, the
|| || || || || || || || ||
closed loop response for a set point change with be
|| || || || || || || || || ||
, different. This is because of the inverse response that
|| || || || || || || || ||
happens with right half plane zeroes. || || || || ||
What is the difference between servo control and
|| || || || || || || ||
regulatory control? - CORRECT ANSWER(S)✔✔Servo || || || || ||
control is based on setpoint changes while regulatory
|| || || || || || || ||
control is based on fixed set point. Regulatory control is
|| || || || || || || || || ||
concerned with rejecting the effect of disturbances. || || || || || ||
In relation to the units of the gain of a process, what are
|| || || || || || || || || || || || ||
the units of the controller gain? - CORRECT
|| || || || || || || ||
ANSWER(S)✔✔The units of process gain and controller || || || || || || ||
gain are inverses of each other.
|| || || || ||
What is proportional kick and derivative kick? -
|| || || || || || || ||
CORRECT ANSWER(S)✔✔Proportional kick is a sharp || || || || || ||
change in the proportional action resulting from a
|| || || || || || || ||
change in the set point. Derivative kick is a sharp change
|| || || || || || || || || ||
in the derivative action resulting from a change in the
|| || || || || || || || || || ||
set point. ||
What would happen if a direct-acting or reverse-acting
|| || || || || || || ||
controller is incorrectly specified? - CORRECT || || || || || ||
ANSWER(S)✔✔If a direct-acting or reverse-acting || || || || ||
controller is not correctly specified, a positive feedback
|| || || || || || || ||
controller will result and the control loop will become || || || || || || || || ||
unstable
Questions With Answers || ||
What is the characteristic equation of a feedback loop
|| || || || || || || || ||
and what is its significance? - CORRECT
|| || || || || || ||
ANSWER(S)✔✔The characteristic equation is the || || || || ||
denominator of the transfer function. The roots of this || || || || || || || || ||
equation are known as poles and determine the dynamic
|| || || || || || || || ||
behavior of the process. If the poles are real and || || || || || || || || || ||
negative, the dynamic behavior is overdamped. If the || || || || || || || ||
poles are complex, the dynamic behavior is oscillatory. If
|| || || || || || || || ||
the poles are real and positive, the dynamic behavior is
|| || || || || || || || || ||
unstable.
What do the transfer function for the closed-loop
|| || || || || || || ||
response indicate about the dynamics of feedback || || || || || || ||
systems for setpoint changes and disturbance rejection?
|| || || || || ||
- CORRECT ANSWER(S)✔✔A closed loop transfer
|| || || || || || ||
function means that the poles will be the same for
|| || || || || || || || || ||
setpoint changes and disturbances. For example, if a
|| || || || || || || ||
linear process has overdamped closed loop behavior for
|| || || || || || || ||
setpoint changes, it will also have overdamped closed
|| || || || || || || ||
loop behavior for disturbance upsets. However, if a
|| || || || || || || ||
positive zero is added with the disturbance rejection, the
|| || || || || || || || ||
closed loop response for a set point change with be
|| || || || || || || || || ||
, different. This is because of the inverse response that
|| || || || || || || || ||
happens with right half plane zeroes. || || || || ||
What is the difference between servo control and
|| || || || || || || ||
regulatory control? - CORRECT ANSWER(S)✔✔Servo || || || || ||
control is based on setpoint changes while regulatory
|| || || || || || || ||
control is based on fixed set point. Regulatory control is
|| || || || || || || || || ||
concerned with rejecting the effect of disturbances. || || || || || ||
In relation to the units of the gain of a process, what are
|| || || || || || || || || || || || ||
the units of the controller gain? - CORRECT
|| || || || || || || ||
ANSWER(S)✔✔The units of process gain and controller || || || || || || ||
gain are inverses of each other.
|| || || || ||
What is proportional kick and derivative kick? -
|| || || || || || || ||
CORRECT ANSWER(S)✔✔Proportional kick is a sharp || || || || || ||
change in the proportional action resulting from a
|| || || || || || || ||
change in the set point. Derivative kick is a sharp change
|| || || || || || || || || ||
in the derivative action resulting from a change in the
|| || || || || || || || || || ||
set point. ||
What would happen if a direct-acting or reverse-acting
|| || || || || || || ||
controller is incorrectly specified? - CORRECT || || || || || ||
ANSWER(S)✔✔If a direct-acting or reverse-acting || || || || ||
controller is not correctly specified, a positive feedback
|| || || || || || || ||
controller will result and the control loop will become || || || || || || || || ||
unstable
