For a pneumatic transmission system for instrumentation purposes, if a pneumatic pressure indicator has a calibrated scale of 0 to 5000 psig, what would be the actual measured pressure if the transmitted pneumatic signal pressure to the indicator is 6 psig, assuming the industry standard of 3 to 15 psig is used for instrument air?

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Accepted Answer

Option B: 1250 psig. Using the 3-15 psig standard, the signal span is 12 psig. A 6 psig signal represents 25% of the span (6-3=3; 3/12=0.25). Applying this to the 5000 psig range, 25% of 5000 equals 1250 psig. This linear scaling is fundamental for pneumatic instrumentation calibration in shipboard control systems.