HVAC Controls Final Quiz
Open Loop
Closed Loop
Direct acting
Reverse Acting
Non self-regulating (astatic or integral system, I-systems)
Self-regulating (static or proportional systems, P-systems)
Tn
Tv
Ks
Kd
Xh
The setpoint can't be achieved if the maximum disturbance variable occurs
The control loop tends to oscillate
One storage element
One control system
One slave controller
Increases
Decreases
Doesn't change
Description via step response
Description by the Ziegler-Nichols method
Description by the control variable response
Description via the frequency response (harmonic response)
Manipulated variable step response
Disturbance variable step response
Xp
Xh
Yh
Tv
Electric resistance element
Water
Agitator
Thermometer
Tank Insulation
Yes
No
Has a steeper slope
Has a gentler slope
Balancing Time, Delay Time, Time Constant
Time Constant, Balancing Time, Delay Time
Delay Time, Time Constant, Balancing Time
Delay Time, Balancing Time, Time Constant
The control range of a control system
The controllability of a controlled system
The reaction time of a controlled system
S
S=0.1...0.3
S>0.3
Higher, longer
Higher, shorter
Lower, longer
Lower, shorter
Closed Loop
Open Loop
Powered controllers
Self-actuated controllers
Less than 0
Greater than 0
Two-position
Modulating
Non-modulating
Quasi-modulating
Larger, smaller
Smaller, greater
True
False
As a hygrostat to switch the humidifier of a room humidity control system
As a pressostat to switch the compressor of a compressed air station
As a flow temperature low-limit controller in a floor heating system
As a temperature controller for a domestic hot water heater
As a frost protection thermostat in a ventilation system
One-fourth
Half
Three-fourths
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