A liquid-level control system can be configured in either of two ways. with a control valve manipulating flow of liquid into the holding tank (Figure a), or with a control valve manipulating the flow of liquid from the tank (Figure b). Assuming that the liquid- level transmitter always is direct acting,(a) For each configuration, what control action should a proportional pneumatic controller have if the control valve is air-to-open?(b) If the control valve isair-to-close?

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LT LC) LT LC (a) (b)