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Linearity and hysteresis are important characteristics in strain gauges and load cells that affect measurement accuracy. Understanding how to evaluate these properties helps ensure reliable data in various applications.
Understanding Linearity
Linearity refers to how well a sensor’s output corresponds proportionally to the applied load or strain. A linear device produces a consistent response across its measurement range.
To assess linearity, apply a series of known loads or strains and record the output. Plot these values to observe if the response follows a straight line. Deviations from this line indicate non-linearity.
Evaluating Hysteresis
Hysteresis is the difference in sensor output when a load is increased versus when it is decreased. It indicates the presence of residual effects or memory within the device.
To measure hysteresis, apply a load incrementally to a maximum value, then decrease it back to zero, recording the output at each step. The difference between the loading and unloading paths at the same load level reflects hysteresis.
Practical Testing Methods
Common methods include using calibration equipment to apply precise loads and recording the sensor’s response. Repeating tests ensures consistency and accuracy of the measurements.
- Apply incremental loads and record outputs
- Plot response curves to analyze linearity
- Perform loading and unloading cycles to assess hysteresis
- Calculate deviations from ideal behavior