The basic inherent error of the load cell refers to the error when the load cell is not affected by external force under the normal working state, that is, the output when the input of the sensor is zero. These errors are often caused by defects in the manufacturing and assembly process of the sensor itself and cannot be completely eliminated by calibration or adjustment.
The inherent error of the load cell mainly includes the following aspects:
1. Nonlinear error.
The nonlinearity error is due to the nonlinear nature of the load cell's resistance strain gauges. During the measurement process, when the resistance strain gauge is subjected to an external force, its resistance value will change, resulting in a nonlinear error. In order to reduce nonlinearity errors, electrical strain gauges with higher sensitivity are usually used, and temperature and digital compensation are used.
Second, hysteresis error.
The hysteresis error is caused by uneven curing of the adhesive between the load cell's electrical strain gauge and the elastic element, uneven internal stress, etc. When the load cell is subjected to an external force, the deformation of the adhesive and the elastic element is out of sync, resulting in an error where the output signal lags behind the input signal. In order to reduce hysteresis errors, it is necessary to improve the bond strength and curing uniformity of the adhesive, and to use both temperature compensation and digital compensation technology.
3. Sensitivity error.
Sensitivity errors are caused by inconsistent or biased sensitivity of the load cell's electrical strain gauges. During the measurement process, when the resistance strain gauge is subjected to an external force, its resistance value changes by different amounts, resulting in inconsistent amplitude of the output signal. In order to reduce sensitivity errors, resistance strain gauges with higher consistency need to be selected and temperature compensated and digitally compensated.
Fourth, the zero drift error.
Zero drift error refers to the phenomenon that the output signal of a load cell changes over time without any external force. This error is usually caused by the thermal expansion and contraction of the electrical strain gauge, the creep and fatigue of the adhesive, and the stress relaxation of the elastic element. In order to reduce the zero drift error, it is necessary to improve the stability of the resistance strain gauge and elastic element, and to use both temperature compensation and digital compensation technology.
In summary, the inherent error of the load cell can have an impact on the accuracy and stability of the measurement. In order to reduce these errors, a series of measures need to be taken from the aspects of sensor manufacturing, assembly and calibration, such as the selection of high-sensitivity electrical strain gauges, the improvement of the adhesive's bond strength and curing uniformity, temperature compensation and digital compensation, etc. At the same time, the sensor also needs to be calibrated and maintained regularly during use to ensure the stability and reliability of its performance.