The level in a drain collection tank is being controlled by an automatic level controller and level is initially at the controller setpoint.
Flow rate into the tank causes tank level to increase.
The increasing level causes the controller to fully open a tank drain valve.
When level decreases below the setpoint, the controller closes the drain valve.
Tank level continues to be controlled in this manner within a narrow band above and below the setpoint.
The controller in this system uses __________ control.
A. on-off
B. proportional
C. proportional plus integral
D. proportional plus integral plus derivative
Show Answer
Answer: A
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