Loadometer principle and the revelation of cheating

The development of loadometer is an indispensable part of national economic development. The traditional loadometer is a weighing instrument composed of analog sensors and secondary display instruments.  The sensor assembly of the weighing system is connected to the secondary analog instrument through the analog signal and the analog junction box to display the number. 
 
From the type of sensor, most of the loadometer sensors use resistance strain gauge pressure sensor, its principle is to transform the strain change into a kind of electrical signal.  The resistance value of the strain gauge is changed, so that the voltage applied to the resistance is changed, which is amplified by the subsequent instrument amplifier and uploaded to the processing circuit (usually A/D conversion and CPU) display or execution mechanism.  However, the resistance-impedance and sensitivity are small, the stability characteristic is not very good, and the 4-wire connection is easy to be affected by the external temperature change and electromagnetic interference.  Driven by interests, some unlegal people use the "traditional" electronic truck scale design defects and simulation sensor performance defects and management loopholes, to install remote control or modification of junction box, change the value of resistance and other means to destroy the measurement accuracy of electronic weighing device, malicious fraud criminal activities.  But the traditional junction box has no anti-norm measure, adjust the potentiometer in the junction board casually, change the resistance value can change the weighing result.  Some criminals use secondary instrument circuit board mounted pressure limiting device, the input circuit, measuring method such as the benchmark magnification change mould Signal processing results, in order to obtain interest, serious damage to national unity of the value and the normal order of fair trading, to social and economic development and social stability to bring great hidden trouble. 
 
In order to maintain the normal order of market, promote the development of science and technology update, in recent years, electronic scale merchants gradually into the high technology content, performance, stability of digital sensors and instruments in the process of new product development and production, by the way of digital terminal box, the analog signal amplification, hardware filtering, AD conversion part of the transition to the junction box,  Complete the signal digitalization between instrument and junction box.  But at present, the ability of domestic weighing apparatus enterprises to directly produce and assemble all digital sensors and meters is very weak, and only a few enterprises with proprietary intellectual property rights can produce such high-end products.  Most enterprise products for analog sensor output signal, or by a junction box to secondary instrument to realize digital, due to continue to use the analog sensor, sensor and signal transmission between junction box is still analog signal, combined with the junction box moistureproof performance factors, such as installation and debugging is still need to be adjusted Angle difference.  Although in recent years, the manufacturer will launch analog signal amplification, hardware filtering, AD conversion part concentrated in a digital terminal box, but continue to use the analog sensor, the sensor signal transmission between the junction box is still analog signal, at the same time terminal box line is complex, more up to 8 road amplifier and the AD conversion device, interfere with each other,  The temperature and humidity required by the analog circuit is difficult to maintain stability, and the anti-disturbance ability is poor, so the connection sensor still needs to be re-calibrated.  Digital advantages are hard to come by. 
 
The real digital mode is to assemble analog signal amplification, hardware filtering, AD conversion, and stabilized power supply in a box, and then hang the box on the analog sensor base or elastic body, commonly known as backpack type digital sensor.  At this time, the sensor, junction box and instrument signal transmission are digital modeling, there is no adjustable device in the junction box of this mode, can not be directly connected to cheating, effectively control the illegal elements using electronic weighing apparatus to commit crimes, obtain illegal interests.  The real digital model of electronic weighing apparatus is the analog signal amplification, hardware filtering, AD conversion, stable power supply part embedded in the sensor elastic body, sensor output is a complete digital signal.  Because the embedded module is built-in and sealant plus laser seal, protection grade up to IP67, emc performance improved obviously, implements the integration of sensor calibration, linear index and sensitivity of highly consistent, interchangeable, effectively improve the ability of the fan, to ensure that countries value unification, to achieve a fair deal, provides the technical support.