Refer to the drawing of a water storage tank with an automatic level control system ___

Refer to the drawing of a water storage tank with an automatic level control system (see figure below).

Given:

• The drain valve fails open on loss of controller output signal.
• The level sensor output signal changes directly with tank water level.

For proper automatic control of tank water level, the controller must be __________; and the control loop must be __________.

A. direct-acting; open
B. direct-acting; closed
C. reverse-acting; open
D. reverse-acting; closed

Show Answer

Answer: D

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