How to select a weighing sensor in a weighing system

Load CellThere are many factors to consider when selecting, and in actual use, we mainly consider the following factors. Additionally,The sensitivity, maximum graduation number, and minimum calibration graduation value of weighing sensors are also indicators that must be considered in sensor selection.

(1) Number and range of sensors

The selection of the number of sensors is based on the purpose of the electronic scale and the number of points that the scale body needs to support (the number of support points should be determined according to the principle of the geometric center of gravity of the scale body overlapping with the actual center of gravity). Generally speaking, a few sensors are selected for the scale body with several support points.
The range selection of sensors can be determined based on the maximum weighing value of the scale, the number of sensors selected, the weight of the scale body, the maximum deviation load that can be generated, and the comprehensive evaluation of dynamic load factors. Generally speaking, the closer the range of a sensor is to the load assigned to each sensor, the higher the accuracy of its weighing. However, in practical use, due to the load added to the sensor, in addition to the weighed object, there are also loads such as the weight of the scale body, tare weight, eccentric load, and vibration impact. Therefore, when selecting a sensor, many factors should be considered to ensure the safety and lifespan of the sensor. Below is an empirical formula that has been validated through extensive experiments.

The formula is as follows:

C=K0& Times; K1& Times; K2& Times; K3 (Wmax+W)/N

In the formula, C is the rated range of a single sensor

W - Self weight of the scale body

Wmax - The maximum value of the net weight of a weighed object

N is the number of support points used for the scale body

K0- insurance coefficient, usually between 1.2 and 1.3

K1- Impact coefficient

K2- Center of gravity shift coefficient of the scale body

K3- Wind pressure coefficient

(2) Accuracy level selection of sensors

The accuracy level of weighing sensors includes technical indicators such as nonlinearity, creep, repeatability, hysteresis, sensitivity, etc. When selecting, one should not blindly pursue high-level sensors, but should consider the accuracy level and cost of electronic scales. In general, the total accuracy of the selected sensor is slightly higher than the accuracy of the scale, with the root mean square value of the sum of the three indicators of nonlinearity, non repeatability, and hysteresis.

(3) The application range and purpose of various types of sensors

The choice of weighing sensor form mainly depends on the type of weighing and installation space, ensuring proper installation and safe and reliable weighing; On the other hand, we need to consider the manufacturer's suggestions. For sensor manufacturers, it generally specifies the force situation, performance indicators, installation form, structural form, and material of the elastic body of the sensor. For example, aluminum alloy cantilever beam sensors are suitable for electronic pricing scales, platform scales, table scales, etc; The steel cantilever beam sensor is suitable for electronic belt scales, sorting scales, etc; Steel bridge type sensors are suitable for track scales, truck scales, etc; Column type sensors are suitable for truck scales, dynamic track scales, large tonnage hopper scales, etc. Weighing sensors are mainly used in various electronic scales, industrial control fields, online control, safety overload alarms, material testing machines, and other fields. Such as electronic truck scales, electronic platform scales, electronic forklifts, dynamic axle load scales, electronic hook scales, electronic pricing scales, electronic steel scales, electronic track scales, hopper scales, ingredient scales, canned scales, etc.

(4) Usage environment

A weighing sensor is actually a device that converts a quality signal into a measurable electrical signal output. When using a sensor, the first thing to consider is the actual working environment in which the sensor is located. This is crucial for the correct selection of sensors, as it relates to whether the sensor can work properly, its safety and service life, and even the reliability and safety of the entire weighing instrument. In general, high-temperature environments can cause problems such as melting of coating materials, melting of solder joints, and structural changes in the stress inside the elastic body for sensors; The impact of dust and humidity on short circuits of sensors; In highly corrosive environments, it can cause damage to the elastic body of the sensor or generate short circuits; Electromagnetic fields can interfere with the sensor output. Under the corresponding environmental factors, we must choose the corresponding weighing sensor to meet the necessary weighing requirements.