Name two common sensor errors and how to diagnose them in a lab.

• A. Offset and drift; diagnose by cross-calibration with a reference, or compare to another sensor and check for sensitivity.
• B. Hysteresis and backlash; diagnose by replacing the sensor.
• C. Sensor saturation and noise; diagnose by increasing sampling rate.
• D. Wiring faults and grounding issues; diagnose by continuity tests.

Answer: (A)

When evaluating sensors in a lab, you’re testing for a fixed bias and for changes in that reading over time. Offset is a constant difference between the sensor output and the true value, while drift is a gradual change in the output as time passes, even if the input stays the same.

The best way to diagnose these is to use a trusted reference or another sensor exposed to the same input and compare results. If the readings sit consistently above or below the reference by a constant amount across the measurement range, you’re seeing offset. If the difference between the sensor and the reference grows or changes over time, or varies with factors like temperature, you’re observing drift. It also helps to verify the sensor’s scaling by applying several known input levels and ensuring the output changes proportionally (checking the sensitivity or slope).

Other approaches described in the other options involve issues that aren’t about offset or drift. Hysteresis and backlash are mechanical or material-memory effects, not fixed bias or time-based change, and replacing the sensor isn’t a diagnostic method for those biases. Saturation and noise relate to range limits and random fluctuations; increasing sampling rate alone doesn’t diagnose persistent offset or drift. Wiring faults and grounding issues are electrical connectivity problems that show up differently and are diagnosed with continuity and grounding checks, not with cross-calibration for bias and drift.