Key Points for Selecting Weighing Sensors of High - precision Dynamic Checkweighers

2025-02-07

High - precision dynamic Checkweighers have high requirements for stability. When the usage time reaches the specified period, it is necessary to recalibrate them to determine whether the performance of the sensors has changed. In some cases, the sensors can be used for a long time with a low frequency of replacement or calibration. Therefore, the requirements for the stability of the selected sensors are even more stringent, and it is necessary to ensure that they can withstand long - term use. Based on this, the selection of appropriate weighing sensors should be considered from the following aspects.

I. Selection of Stability

After being used for a certain period, the ability of a high - precision weighing sensor to maintain its performance unchanged is defined as stability. Besides the sensor's own structure, the operating environment is the main factor affecting its long - term stability. Therefore, to ensure that the sensor has good stability, it must have a strong environmental adaptability. Before selecting a sensor, a detailed investigation of its operating environment should be carried out, and an appropriate sensor should be selected according to the specific operating environment, or appropriate measures should be taken to reduce the impact of the environment. The impacts of the environment on high - precision weighing sensors are as follows:

High - temperature environments can cause the melting of the sensor's coating material, the cracking of solder joints, and the change of the stress structure inside the elastomer.

Dust and humidity can cause short - circuit effects on the sensor.

In highly corrosive environments such as high humidity and high acidity, the elastomer is prone to damage, or short - circuits may occur due to humidity and acidity.

Electromagnetic fields can disturb the signal output by the sensor.

In flammable and explosive environments, special explosion - proof sensors must be selected.

II. Selection of Sensitivity

Generally, within the linear range of the sensor, the higher the sensitivity, the more conducive it is to signal processing. This is because when the sensitivity is high, the output signal value corresponding to the measurement is relatively large. However, while the sensitivity is high, external noise unrelated to the measurement will also be amplified, thus affecting the measurement accuracy. Therefore, the sensor itself should have a high signal - to - noise ratio and minimize the interference signals introduced from the outside.

III. Selection of the Number of Sensors and the Measuring Range

The number of sensors in a high - precision dynamic checkweigher is determined according to the usage of the electronic weighing device and the number of support points required for the weighing body (the determination of support points should follow the principle that the geometric center of gravity of the weighing body coincides with the actual center of gravity). The selection of the measuring range of the sensor needs to be determined by comprehensively evaluating the weighing value of the scale, the number of selected sensors, the self - weight of the weighing body, the eccentric load, and the possible dynamic load. According to experience, the working range of the sensor should be between 30% and 70% of its full scale. For weighing instruments with a large impact force, when selecting a sensor, it is usually necessary to make the sensor work within 20% of its measuring range to ensure the safety and service life of the sensor.

IV. Selection of Accuracy

Accuracy is an important indicator for measuring the performance of a weighing sensor. Generally speaking, the higher the accuracy, the higher the price. Therefore, it is only necessary to ensure that the accuracy of the sensor meets the required weighing accuracy requirements, and there is no need to choose a product with excessively high accuracy.