A.should be kept at a proper level by a cooler
B.should be raised to about 80℃ by a heater
C.should be raised gradually
D.should be lowered to about 60℃
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A.operational
B.open
C.closed securely
D.at middle position
A.instigating corrective action
B.indicating values of controlled variables
C.warning of off-limit conditions
D.providing record of performance
A.which governs the state of a variable
B.which provides a visual and audible alarm
C.which indicates values of controlled variables
D.which measures the state of the controlled variable
A.the lack of a feedback
B.the presence of a feed back
C.the lack of a computer
D.the presence of a computer
A.two-step controller action
B.proportional, controller action
C.integral controller action
D.derivative controller action
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