In electronic measurement technology, the term used is Offset, when the actual measured value differs from the correct value by a constant amount—even when the applied input signal is zero. This phenomenon is therefore also referred to as Zero-point shift or zero-point error: Instead of displaying a value of zero for an input signal of 0 V or 0 mA, the measuring system exhibits a small, systematic offset. This error is independent of the magnitude of the actual measurement signal and is added as a constant value to every measured result.
How does an offset occur?
Offsets occur particularly frequently in Measurement amplifiers based on operational amplifiers for voltage signals. Although operational amplifiers are theoretically designed to be perfectly symmetrical, manufacturing tolerances of the individual semiconductor components always result in slight asymmetries during actual production. This results in a small voltage being present at the output even without an input signal—the so-called offset error. This effect is further amplified by external influences: temperature fluctuations alter the electrical behavior of the components, and the natural Aging of Electronic Components This can cause the zero point of a measurement amplifier to shift slowly over time (offset drift). Without appropriate countermeasures, such an error in the measurement chain—which may seem insignificant at first—would systematically affect every single measurement result and compromise the accuracy of the entire measurement data acquisition process.
Why is offset so important in measurement technology?
Especially when measuring small voltage signals—such as those from thermocouples, strain gauges, or other low-level sensor signals—even a small offset can cause a noticeable relative error in the measurement result. Since the offset error is additive and remains nearly constant across the entire measurement range, it cannot be easily eliminated by adjusting the gain—it must be determined and compensated for separately. In high-quality measurement systems, therefore, regular Zero Point Calibration essential for ensuring consistently accurate, comparable, and reproducible measurement results.
Offset Compensation in Delphin Devices
The measuring and testing equipment from Delphin Technology, for example, from the product lines Expert Logger, Loggito or ProfiMessage, feature a built-in Automatic Calibration. At defined intervals, the device automatically performs an internal zero-point calibration without requiring any manual intervention by the user. In this way, offset errors and their variations due to temperature fluctuations and component aging are continuously and automatically compensated for. This continuous self-calibration ensures that Delphin measuring instruments reliably deliver accurate and long-term stable measurement values even over long periods of operation and under varying environmental conditions.