On the market, the load cell called the weighing heart, an output device that converts quality signals into measurable electrical signals. Its performance determines the accuracy and stability of electronic weighing to a large extent.
Four elements of load cell selection
One: the stability of choice
After a period of use of the load cell, its properties and capabilities remain unchanged, with known stability. The long-term stability of the impact load cell is in addition to its own structure and the environment in which it is used. Therefore, to make the load cell have good stability, it must have a strong ability to adapt to the environment. Before selecting a load cell, investigate the environment in which it should be used, and select the appropriate load cell according to the specific use environment, or take appropriate measures to reduce the impact on the environment.
Environmental pressure transmitter will cause the following effects:
The high temperature environmental load cell coating material melts, the solder joint is civilized, and the stress structure of the elastomer changes.
Dust in the open air, the humidity load cell causes a short circuit.
In a high corrosive environment, such as humidity, acidity, the load cell causes damage or short-circuit elastomer.
The electromagnetic field disturbs the signal output by the load cell.
In flammable and explosive environments, special explosion-proof load cells must be used.
should be recalibrated to determine whether the changed performance of the load cell is a quantitative indicator of the stability of the used load cell. In the long-term use and cannot be easily replaced or calibrated, the stability requirements of the selected load cell are more stringent, and the load cell must be able to withstand the test and extend certain requirements.
Second: the sensitivity of choice
Normally, within the linear range of the load cell, it is ideal that the higher the sensitivity, the better. Because only the sensitivity is high, the measurement of the corresponding output signal value is relatively large, which is conducive to signal processing. The independent external noise will be amplified by the amplification system to affect the measurement accuracy, high-sensitivity measurement. Therefore, the load cell itself should have a high signal-to-noise ratio, and the interference introduced from external signals should be minimized.
Third: the number and range of load cells
The number of load cells is selected according to the number of support points that the body of the electronic scale needs to use (in principle, it should be determined according to the geometric center of gravity of the support point and the actual center of the center of gravity of the scale).
The largest scale of the load cell, the weight of the scale, the largest possible partial load and the dynamic load factor are evaluated to determine the number, and the selection can be selected based on the load cell range. Generally, it should be based on the working experience of the load cell in the range of 30% to 70%, but there are larger choices of impact load cells, generally in the range of 20% to 30%, so that the load cell works to ensure load cells and life for safe use
Finally: Choose accuracy
Accuracy is an important performance index of the load cell, and it is related to an important part of the measurement accuracy of the entire measurement system. The higher the accuracy of the load cell, the more expensive it is, so as long as the accuracy of the load cell can meet the accuracy requirements of the entire measurement system, don’t choose it. So, you can choose a cheaper and simpler load cell among many load cells to meet the same measurement purpose. If the measurement results are qualitatively analyzed, a load cell with high repeatability should be used. High-precision absolute magnitudes should not be used. If quantitative analysis is performed, it is necessary to obtain accurate measurement results. load cell pressure transmitter that meets the requirements.
Accuracy selection to meet the following two conditions:
Meet the requirements of instrument input. The output signal of the load cell must be greater than or equal to the input signal required by the instrument.
Meet the accuracy requirements of the entire electronic scale. An electronic scale body composed of three parts, load cells, instruments, and the accuracy of the load cell is that the accuracy of the selected load cell is slightly higher than the theoretical value.