Question 14

The Correct Answer is A **Explanation of why Option A is correct:** The term "span" in instrumentation refers to the difference between the upper range limit (URL) and the lower range limit (LRL) of the measurement or output. The question states that the *process output* being controlled/calibrated against has a range of $50-250 \text{ psi}$. Span = Upper Limit - Lower Limit Span = $250 \text{ psi} - 50 \text{ psi} = 200 \text{ psi}$. Therefore, the output process span is $200 \text{ psi}$. **Explanation of why other options are incorrect:** * **B) Output process range is $0-250 \text{ psi}$.** This is incorrect because the question explicitly states the process output range is $50-250 \text{ psi}$. The $0 \text{ psi}$ is not the specified lower range limit (LRL). * **C) Controller process output span is $0-250 \text{ psi}$.** This statement incorrectly mixes the concepts of span and range. A span is a single value ($200 \text{ psi}$), not a range ($0-250 \text{ psi}$). Furthermore, the specified span is $200 \text{ psi}$ (from $50 \text{ psi}$ to $250 \text{ psi}$). * **D) Controller input ranges are $0-40 \text{ mA}$ and $0-15 \text{ psi}$.** While $0-15 \text{ psi}$ (or commonly $3-15 \text{ psi}$) is the standard range for pneumatic control signals, and $4-20 \text{ mA}$ (not $0-40 \text{ mA}$) is the standard for electronic control signals, these ranges represent the *input/signal* to the controller, not the *output process span* ($50-250 \text{ psi}$) the question asks about in relation to the calibration.