Traditionally, the load cell is a general term for load cells and load cells, and its measurement characteristics are evaluated by a single parameter. The old national standard considers the application object and the “weighing” and “measuring force” sensors that use completely different environmental conditions, and does not distinguish between the test and the evaluation method. There are 21 indicators in the old national standard, all tested at room temperature; and the weighing is determined by the maximum error among the six indicators of nonlinearity, hysteresis error, repeatability error, creep, zero temperature additional error and rated output temperature additional error. The sensor accuracy levels are indicated by 0.02, 0.03, and 0.05, respectively.
A force sensor used on the scale. It converts the gravity acting on the object to be measured into a quantifiable output signal. Considering the influence of gravity acceleration and air buoyancy on the conversion of different places of use, the performance indicators of load cells mainly include linearity error, hysteresis error, repeatability error, creep, zero temperature characteristic and sensitivity temperature characteristic. In various scales and mass measurement systems, the integrated error is usually used to comprehensively control the sensor accuracy, and the integrated error band is linked with the instrument error band (Fig. 1) to select the weighing device corresponding to an accuracy scale. sensor. The International Organization of Legal Metrology (OIML) stipulates that the error band δ of the sensor occupies 70% of the error band Δ of the instrument, the linearity error of the load cell, the hysteresis error, and the error caused by the influence of temperature on the sensitivity within the specified temperature range. The sum cannot exceed the error band δ. This allows the manufacturer to adjust the individual components that make up the total measurement error to achieve the desired accuracy.
Advantages: Insensitive to change of loading point, good anti-offset performance, good inherent linearity, convenient installation, fixed and non-rotating load cell, low manufacturing cost.
Disadvantages: The center of gravity is high and the overload capability is poor. It is difficult to achieve a high accuracy level for weighing instruments with large weighing.
