Arrhenius Acceleration Kinetics for Encapsulated Sensor Polymers
Arrhenius acceleration models for sensor encapsulation polymers require activation energy mapping across glass transition bounds to prevent unearned drift extrapolation.
Span Sensitivity Drift
Sensitivity Drift
The slope of a sensor’s transfer function determines the ratio between the change in output signal and the change in measured input. A span sensitivity drift represents the change in this slope over time, which alters the full-scale output of the device. It causes the sensor to output an incorrect value that increases proportionally with the magnitude of the measured input.
Drift Mechanism
Aging of the internal electronic components or the transducer element itself is the primary cause of this phenomenon. In pressure transducers, mechanical strain and fatigue in the sensing diaphragm drive the span sensitivity drift during continuous cycling. Thermal cycles and long-term chemical exposure also degrade the materials, modifying the sensor’s sensitivity to the input variable.
This deterioration is often accelerated in environments with high humidity or corrosive gases, which corrode the sensitive transducer metallurgy.
Metrological Identification
Detecting this change requires a multi-point calibration of the sensor over its entire operating range. Comparing the resulting calibration curve to the original factory baseline isolates the span sensitivity drift from simple zero offsets. This comparison is conducted at reference conditions to prevent interference from transient environmental variables.
Compensation Strategy
Modern smart sensors include internal temperature and aging compensation algorithms to minimize this drift. Recalibration and gain adjustments are scheduled periodically to correct for any remaining span sensitivity drift that has occurred. These maintenance actions ensure the sensor maintains its specified accuracy within its intended calibration interval.