Two-point calibration: what parameters are derived?

• A. Zero and span for pressure
• B. Slope and intercept of the output vs level relationship.
• C. Offset and gain only for temperature
• D. Alarm thresholds only

Answer: (B)

Two-point calibration yields a straight-line relationship between the input (the quantity you’re measuring) and the output (the signal you read). From two known reference points, you determine the line y = m x + b, where m is the slope (gain) and b is the intercept (offset). The slope tells you how much the output changes per unit of input, and the intercept tells you what the output would be when the input is zero. With these two parameters, you can convert any measured output to its corresponding input. Zero and span describe the endpoints of that same line in a different way, but the two direct parameters you derive are slope and intercept.