"Zero drift" is a term used in metrology to describe a slow, unpredictable change in the zero point of a measuring device over time. The zero point of a meter is the output value that the device displays when there is no input. Zero drift occurs when this initial value deviates over time, even if there is no input.
For example, when sampling bulk materials, a scale or force sensor could be used to measure the weight or mass of the sample taken. If these sensors have zero drift, they could show a different weight even if there is no sample on the balance. This would lead to inaccurate measurements and possibly unrepresentative samples.
Zero-point drift can be caused by a number of factors, including changes in ambient temperature, mechanical stress, or aging of the sensor. To minimize the effects of zero drift, instruments can be calibrated regularly to ensure they provide accurate measurements. In addition, some modern sensors and meters may have automatic zero correction capabilities that help minimize the effects of zero drift.