In Situ Thermal Aging Calibration Corrections for High Temperature MEMS Transducer Arrays
Dynamic matrix corrections combine in situ reference tracking and Arrhenius modeling to eliminate unbudgeted high temperature MEMS recalibration cycles.
Span Shift Correction
Calibration Adjustment
A calibration adjustment modifies the gain coefficient of a sensor to restore measurement accuracy when its sensitivity has changed over time. The span shift correction process adjusts the slope of the transducer transfer function without altering the zero-point offset. This adjustment is necessary when environmental exposure or component wear changes the full-scale output value.
It ensures that the sensor maintains its rated accuracy across the entire measurement range.
Implementation Mechanism
Reference standards with known physical quantities are applied to the sensor to measure the deviation at the full-scale limit. When the measured output differs from the reference value, a span shift correction is calculated and applied to the calibration registers. This calculation is often combined with temperature compensation to handle sensitivity shifts caused by thermal variations.
The correction is executed by multiplying the digitized output of the analog-to-digital converter by a scaling factor. This scaling factor is stored in the non-volatile memory of the sensor assembly. If the span shift is left uncorrected, the measurement error scales proportionally with the magnitude of the measured signal.
Verification Method
Automated test equipment verifies the accuracy of the updated gain factor before returning the sensor to service. This verification uses multiple calibration points to confirm the span shift correction is successful.
System Stability
Sensing systems require periodic execution of this adjustment to counteract the effects of drift. This routine maintenance uses the span shift correction to extend the useful operating life of the instrumentation.