Evaluating Thermal Hysteresis Limits in MEMS Accelerometer Static Leveling
MEMS thermal hysteresis creates non-repeatable zero-g offset shifts up to 3 mg, driving uncompensable arcsecond tilt errors in static leveling systems.
Temperature Non-Repeatability
Output Variance
Variation in the measurement output of a sensor when it returns to the same temperature after undergoing a thermal cycle. Temperature non-repeatability identifies the inability of an instrument to maintain a consistent baseline following exposure to environmental changes. This phenomenon often results from hysteresis in the mechanical structure or the electronic components.
Internal Hysteresis
Internal stresses in the packaging or the sensing element may shift during expansion and contraction. When the material cools down, it might not return exactly to its original state, leading to a small but measurable change in the output signal. This effect is particularly pronounced in devices made of multiple materials with different thermal expansion coefficients.
Metrological Uncertainty
High-precision applications cannot rely on simple calibration curves if the sensor output depends on its thermal history. A device might show a different zero-point after being heated to eighty degrees than it did before the cycle began. This uncertainty limits the overall precision of the system and necessitates frequent re-zeroing in critical environments.
Thermal Evaluation
Testing involves cycling the device through its full operating temperature range several times. The maximum difference observed at the reference temperature defines the non-repeatability specification. Selecting materials with low hysteresis helps in reducing this error.