Output Instability
Static measurement errors arising from slowly changing thermal gradients and mounting strain in a sensor housing can distort the physical substrate of the sensing element. This long-term instability, known as non dynamic thermo mechanical stress drift, causes a slow shift in the zero-point calibration even when the physical environment is completely stationary. The phenomenon is driven by the mismatched thermal expansion coefficients of the silicon chip, the adhesive, and the ceramic package.
Strain Propagation
Mechanical tension from the circuit board propagates through the solder joints and package to the internal micro-structures. This strain alters the electrical properties of the sensing element through piezoresistive effects, mimicking a change in the physical variable being measured. Isolation techniques, such as compliant mounting gel or flexible leads, are used to decouple the sensor from these external mechanical forces.
Calibration Strategy
Correction of this drift requires exposing the sensor to slow temperature cycles under zero-load conditions. The resulting data points are used to generate a multi-dimensional compensation curve that is applied to the digital output. Field verification of this calibration is typically performed during scheduled maintenance intervals to check for long-term aging effects.
Structural Resilience
Using materials with matched thermal expansion coefficients in the sensor construction reduces the baseline drift.
