单项选择题
A.reset action
B.proportional action
C.two position action
D.rate action
单项选择题 In an automation system, the effect of a control action sensed by a controller is known as （）
单项选择题 The value of the controlled variable, which under any fixed set of conditions the automatic controller operates to maintain, is known as （）
单项选择题 The quantity or condition which is measured and controlled is known as the （）