Performance Characteristics: Hysteresis, Drift, Linearity

Performance Characteristics

Beyond Accuracy and Precision, several other factors determine an instrument's quality.

Hysteresis

The phenomenon where a device shows different output values for the same input, depending on whether the input is increasing or decreasing.

• Example: A pressure sensor might read 50.1 bar when pressure rises to 50, but 50.3 bar when pressure falls back to 50 from 100. Low hysteresis is crucial for consistent control.

Drift (Stability)

The unwanted change in a measurement value over time while the measured quantity remains constant.

• Temperature Drift: Changes caused by ambient temperature fluctuations.
• Long-term Drift: Gradual degradation of the sensor over months or years. High-quality devices like the ZMA Series use temperature-compensated components to minimize drift.

Linearity

(Detailed in Linearity). It is the measure of how well the device's output follows a straight line relative to the input.