Response Lag
Measurement deviations in precision instruments often arise from the lagging of a physical response behind the force that caused it, resulting in a different path during loading and unloading cycles. Strain hysteresis in a sensor structure leads to a non-linear relationship between the applied stress and the resulting measurement. A deviation of this type is often observed in the bonding agents or mounting brackets of an instrument.
Measurement Error
When a sensor is subjected to a mechanical load and then returned to its original state, strain hysteresis prevents the output from returning to zero immediately. A residual offset introduces a bias that depends on the previous state of the system. In inertial sensors, this behavior can appear as a shift in the scale factor or a drift in the zero-point.
Characterization Method
Calibration involves cycling the sensor through its full operating range several times to map the hysteretic loop. The width of this loop indicates the magnitude of the energy loss within the material. High-precision applications require materials with low internal friction, such as quartz or specialized alloys, to minimize this effect.
The environmental temperature often influences the size of the loop, requiring a multi-dimensional calibration table.
Design Limit
Engineers specify a maximum allowable hysteresis as a percentage of the full-scale output. This value is verified during the qualification phase of the product development.
