Which of the following describes sensor span?

• A. Span is the digital encoding width of the signal.
• B. Span is the time delay between input and output.
• C. Span is the difference between calibrated high and low outputs and defines the measurement range.
• D. Span is the power consumption rating of the sensor.

Answer: (C)

Span is the difference between the sensor’s calibrated high and low outputs, and it defines the measurement range the sensor can cover. In other words, the span tells you how much the output can change as the measured quantity goes from its minimum to its maximum, setting the usable reporting window. For example, if a sensor outputs 0.5 V at its low end (0 units) and 4.5 V at its high end (100 units), the span is 4.0 V and the measurement range is 0 to 100 units. This span is what you use, along with the low output, to map the raw signal to real-world values.

The other options don’t fit because the digital encoding width describes how many discrete levels are available (resolution), not the range of measurements; the time delay is about response time or lag between input and output; and the power consumption rating concerns how much energy the sensor uses, not its span.