The level in a tank is controlled by an automatic control system.
Level is initially at its setpoint.
A drain valve is then opened, causing tank level to begin to decrease.
The decreasing level causes the controller to begin to open a makeup supply valve.
After a few minutes, with the drain valve still open, level is again constant at the setpoint.
The controller in this system uses primarily __________ control.
A. integral
B. on-off
C. derivative
D. proportional
Show Answer
Answer: A
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