Question 559General Subjects - Assistant Engineer

The correct answer is C) 15 psig. In an analog electronic transmission system, the industry standard of 4 to 20 mA is used to represent the full range of the instrument's calibrated scale. In this case, the pressure indicator has a calibrated scale of 0 to 30 psig. At 4 mA, the indicator would read 0 psig, and at 20 mA, it would read 30 psig. Since the transmitted signal is 12 mA, which is the midpoint of the 4 to 20 mA range, the actual measured pressure would be 15 psig, which is the midpoint of the 0 to 30 psig calibrated scale. The other options are incorrect because they do not accurately reflect the relationship between the 4-20 mA signal range and the 0-30 psig calibrated scale.