Weighing modules are mainly of piezoelectric, piezoelectric, and resistive strain types. Weighing module utilizes the piezoelectric effect of piezoelectric materials, in the piezoelectric element has a voltage (or charge) output when there is an external force. Piezoelectric sensor small body lightweight, working bandwidth, high mechanical strength, rigidity, small working deformation, good insulation performance, widely used in mechanical vibration, impact and other fields, but only in the case of external forces acting on the piezoelectric material charge without leakage can be saved, therefore, the input impedance of the measurement circuit is very large, difficult to realize, this weighing module is usually used for mechanical force measurement.

Compression magnetic weighing modules work by utilizing the compression magnetic effect of ferromagnetic materials such as nickel, iron-nickel, and ferrosilicon alloys. Compression magnetic weighing module has strong anti-interference ability and overload capacity, low requirements for working conditions, work in harsh environmental conditions (dust, corrosive gases, low temperature and humidity), widely used in metallurgy, mining and chemical fields, but long-term stability and linearity decline.

Resistance strain gauge force gauge is the most widely used, stable, accurate and technically proven force measurement weighing module in the current stage. It is the use of metal elastomer deformation effect conversion, elastomer deformation under the action of the side force p, attached to its deformation of the tensile sheet, resistance changes, resistance changes reflect the size of the force. The advantages of this weighing module are small size, fast response, good linearity, good repeatability, easy to use. The analog part of the measurement module in this paper is the resistance strain weighing module.

All of the above three traditional weighing modules are converted in an analog way, i.e., the target force is converted to the electric quantity in the decision-making relationship (e.g., voltage, charge, current), because the analog (voltage, current) is susceptible to electromagnetic field interference, and it is not good for direct long-distance propagation, so the signal processing system is affected by the semiconductor device itself due to the nonlinear distortion and the gradual increase of random noise, and by the temperature parameter of the electronic parts of the analog circuit, etc. .

At this stage, analog resistance strain weighing modules still occupy the main market due to performance reliability and technical production maturity, but the output signal is very weak because the output of analog weighing modules is analog, and the electronic parts of analog circuits are affected by temperature, which leads to changes in parameters and properties, and it is difficult to control the long term stability, and most importantly, there is no record of analog weighing modules, and the data cannot be saved.

Weighing modules are considered as the nervous system of electronic scales, and their performance depends largely on the accuracy and stability of electronic scales. With the rapid development of science and technology, electronic scales manufactured by weighing modules have been widely used in various industries to achieve fast and accurate measurement of items.

Weighing modules are actually devices that convert mass signals into measurable electrical signal outputs. For the weighing position, the number and range of weighing modules, the range of recapitulation, the accuracy level, the weighing module input to the electronic scale of several aspects, which are related to the working condition, reliability and safety of the weighing. However, there are a number of factors that must be taken into account in the actual use of which weighing modules are used.

1. Weighing modules working in high temperature environments, due to the coating material is prone to melting, brazing blooming, changes in the internal stress of the elastomer, and to install adiabatic, water-cooled or air-cooled devices. Also in highly corrosive environments (e.g. humid or acidic) the elastomers may be damaged or short-circuited, therefore a spray or stainless steel cover should be used on the external surfaces, in order to select a corrosive and hermetically sealed weighing module.

2. Electromagnetic field interferes with the output of the weighing module. Be sure that the signal line of the weighing module is shielded and has good resistance performance to electromagnetic interference.

3. Flammable and explosive environment will not only cause damage to the weighing module, but also pose a great threat to other equipment and personal safety, so the weighing module working in this environment requires more explosion-proof. The sealed shell of this weighing module should not only consider the sealing, but also consider the explosion-proof strength, waterproof, moisture-proof and explosion-proof caused by the cable line.

4. Dust and moisture can also short-circuit the weighing module, so you should use a weighing module with high sealing performance. The sealing status of weighing modules varies greatly according to the sealing method. General sealing is sealant filling or coating. Rubber gasket mechanically fixed sealing; welding sealing box vacuum nitrogen filling sealing.

5. There are also certain specifications for the selection of the number and range of weighing modules. The choice of the number of weighing modules depends on the purpose of the electronic scale, the number of points to be supported by the scale (the number of support points must be determined according to the principle that the center of the shape of the scale coincides with the actual center of mass). Generally, there are several support points on the scale, but some special scales can only use one metrology module, and some electromechanically coupled scales require a decision on the number of weighing modules to be selected according to the actual situation. The selection of the range of weighing modules can be determined by a combination of the evaluated maximum weighing value, the number of weighing modules to be selected, the heavy loads, the maximum possible partial loads and the dynamic loads.

In general, the closer the range of weighing modules is to the load assigned to each weighing module, the higher the metrological accuracy. However, in practice, in addition to the loads applied to the weighing module called objects, there are also loads such as heavy loads from the metering equipment, weights being weighed, partial loads, and vibration shocks. Therefore, a variety of factors must be taken into consideration when selecting the range of the weighing module to ensure the safety and longevity of the weighing module.

The range of application of various weighing modules should again be considered. The selection of the type of weighing module depends mainly on the type of weighing and the footprint to ensure proper installation, safe and reliable weighing; on the other hand, it is necessary to take into account the recommendations of the manufacturer, who usually specifies the range of the sensor's compound cover according to the stress of the weighing module, its performance indexes, the form of mounting, the type of structure, the elastomeric material, etc., e.g., electronic weighing scale, platform weighing scale, tribal elastomeric sensors. Steel cantilever weighing modules, suitable for hopper scales, electronic belt scales, etc.; steel bridge weighing modules are suitable for grounded pounds, electronic scales, etc. Column weighing modules are suitable for reaction kettles, storage tanks, large tonnage hopper scales, etc.

It is also necessary to choose the accuracy level of the load cell. The accuracy level of the load cell includes technical indicators such as nonlinearity, creep, delay, iteration and sensitivity of the sensor. When choosing a weighing module, do not just pursue advanced weighing modules, but also consider the accuracy requirements of the electronic scale and the cost of use. Meet the accuracy requirements of the entire electronic scale. An electronic scale is mainly composed of three parts: scale, weighing and weighing, and when choosing the accuracy of the weighing module, the accuracy of the weighing module should be slightly higher than the theoretically calculated value. Because the theory is often limited by objective conditions such as a slight decrease in the strength of the longitudinal body, and there are many factors such as the performance of the meter is not very good, or the scale's working environment is poor.