Signal Instability
Slow changes in the output of a sensor occur when no input is being applied to the device. Zero offset wander represents the long-term drift of the baseline signal over time or temperature. This phenomenon can obscure small signals and introduce errors in static measurements.
Causal Factor
Aging of components or internal stress relaxation in the sensing element drives the change. In zero offset wander, the electrical or mechanical equilibrium of the sensor shifts gradually.
Measurement Protocol
Tracking the output over hundreds of hours in a controlled environment identifies the rate of drift. Quantifying zero offset wander requires a stable environment where the input is held at exactly zero.
Mitigation Technique
Auto-zero circuits or periodic recalibration can minimize the impact on the final data. Zero offset wander is a factor in selecting sensors for long-term monitoring where manual adjustment is not possible. Verification involves checking the sensor against a known zero reference at regular intervals during its service life.
The drift is often reported as a maximum voltage or current deviation per month of operation. Testing occurs at a constant temperature to separate the temporal wander from thermal effects. The final stability specification allows engineers to determine the required interval for system maintenance and re-zeroing.
