Test #1 Flashcards
Give an example of a human control system.
The iris of the eye changes the size of the pupil to control the level of light that hits the retina to allow for optimum viewing.
Identify 3 simple open-loop control systems seen in everyday life. In each case,
identify the controlled variable, the manipulated variable, the disturbance variable,
and the objective(s) of the control system.
A) Define Closed-Loop and Open-Loop Control Systems.
Open-Loop is a type of control system that does not use feedback.
A closed-loop control system is a control system that uses feedback.
B) Give an advantage of each type of Control System.
The open-loop control system is simple an inexpensive. The closed-loop control system provides more accurate control of the controlled variable and will automatically adjusts to changing disturbances.
Identify 3 simple closed-loop control systems seen in everyday life. In each case,
identify the controlled variable, the manipulated variable, how feedback is
achieved, at least 1 disturbance, and the objective of the system.
Oven Temperature Control System
Well Water System
Dehumidifier
# Define the following terms: Controlled Variable, Manipulated Variable,
Disturbance Variable, Error, and Set point.The controlled variable is the process variable whose value is managed or regulated by the control system.
The manipulated variable is the process variable whose value is adjusted by the actuator to influence the value of the controlled variable.
The disturbance variable is the process variable which can influence the value of the controlled variable and yet cannot be influenced by the control system.
Error: The controller signal created by subtracting the measured value of the controlled variable from the setpoint.
Setpoint: The desired value of the controlled variable or the input to the control system.
How is the output of the Measurement Transmitter potentially different than the
controlled variable?
The output of the measurment transmitter represents the controlled variable with a different unit and may have some errors as the result of the measurement.
State the makeup of the measuring transmitter.
The measurment transmitter is made up of a sensor and a signal conditioner
Name the three operations performed by a feedback control system.
Measurement
Computation
Manipulation
Why didn’t the speed (in Figure 7B of the notes) return to it pre-disturbance value?
The speed in a closed loop control system will not necessarily return to its pre disturbance value unless Integral mode control is part of the control modes utilized.
What can we determine from the difference between the drop that occurred in
figure 7A versus the drop that occurred in figure 7B right after the load was applied?
We can tell by the differences in the drop that the closed loop control system responds faster and allows less maximum error than the open loop control system.
What relationship in a component is defined by the Transfer Function?
The size and timing relationship between the input and output signals of a component are defined by the transfer function.
A) Name the 3 objectives of a control system.
Minimize the maximum error
Minimize the settling time
Minimize the residual or remaining error
B) Name the 4 criteria of a good control system
Critical Damping
Minimum Integral of Absolute Error
Quarter Amplitude Decay
Peak Percentage Overshoot
A) Name and draw the 5 different possible control system step responses we
discussed in class.
