Improvement and error analysis of the hottest dyna

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Improvement and error analysis of dynamic track scale system × The 350 MW large-scale thermal power plant consumes more than 1million tons of raw coal per year. In order to improve the labor productivity and economic benefits of the whole plant, we must check the weight and quality of thousands of tons of raw coal every day. This requires that the dynamic track scale system has stable performance, high measurement accuracy, long-term safe and continuous operation, so that the incoming raw coal can be accurately measured, and the completion of weight inspection and quality inspection rate can be guaranteed, so as to reduce the cost of power generation

the improvement of gcu-100g dynamic track scale system and the analysis of measurement error are introduced below

1 working principle

as shown in Figure 1, the mechanical weighing table transmits the weight of the weighed vehicle to the sensor, which converts the weight signal into the corresponding voltage signal and inputs it into the secondary instrument control system. The electrical channel of the control system amplifies, filters and a/D converts the input voltage signal into the corresponding digital signal and sends it to the computer system. The computer program software includes self-test, data acquisition, signal processing, waveform recognition, etc. Finally, the weighing results are automatically displayed and printed through the display and printer, so as to complete the whole dynamic measurement process of the vehicle

2 improvement of track scale system I have helped track scale personnel install and debug to the line, and there have been many failures. It has mechanical aspects, power supply aspects, secondary instruments, installation aspects and so on. To this end, we have carried out research on the track scale system in all aspects. The space technology mission command (STMD) of NASA has shown great interest in nanotechnology and made some improvements

2.1 a 6000 V/220 V transformer is installed in the power supply to realize the single-phase independent power supply of the track scale system, which effectively prevents the influence of the external circuit with resistance and capacitance components on the metering equipment

2.2 an isolation transformer is installed between the secondary instrument and the regulated power supply. Small storage value setting: the user sets a small storage value according to the storage demand

2.3 adjust the adjusting screw of the mechanical table limit device mechanically, so that the main beam is in the correct working position in the main frame, which can not only overcome the transverse thrust and impact force generated when the train passes, but also transmit the real weight of the train to the sensor

2.4 four sensors were replaced. At the same time, adjust the four sensors to make them bear the force evenly, ensure that the weighing main beam and the sensor shell are well grounded, and improve the anti-interference ability of the sensor

2.5 the channel plug-in is improved, so that it has high stability, low noise and anti-interference ability when completing the functions of signal sampling, amplification, filtering and a/D conversion

2.6 the new microcomputer configuration is:

host: Lenovo lx-p5/150pci hard disk: 1.2 GB

memory: 8 MB display: sc-428ps color display

3 error analysis

3.1 mechanical error of weighing table

the weight of the loaded train is used as a sensor through the mechanical table. Due to some adverse factors in the mechanical structure, The force borne by the table cannot be truly transmitted to the sensor, resulting in error. The mechanical part of the table bears the impact of train weight and vibration for a long time, so it needs to be checked and adjusted regularly, otherwise it will affect the measurement accuracy and driving safety

3.2 error of load cell

load cell is the fulcrum of force on the table of weighing machine, and it is the conversion part of the charge and burst signal of the measured force. The common performance directly affects the measurement coarseness and stability of the whole system. The error is mainly caused by the nonlinearity, non repetition, hysteresis and other characteristics of the sensor itself, which is directly related to the material selection and manufacturing process of the sensor. During the use of the sensor, due to the change of the surrounding environment, it will also cause its zero drift and coefficient change

3.3 dynamic weighing error

when the weighing train does not take off the hook during operation, it will cause dynamic weighing error and affect the measurement accuracy by speeding through the mechanical table, sudden acceleration, deceleration and emergency braking in the measurement process

3.4 secondary instrument system error

when the secondary instrument channel component realizes the functions of signal sampling, amplification and a/D conversion, it is likely to introduce strong magnetic field interference, amplifier zero drift, noise and other errors that affect the measurement accuracy. However, the errors of sampling speed and waveform misjudgment are also prone to occur in the operation of microcomputer system software symmetric system self-test, interrupted sampling, waveform recognition, data management display and printing. Therefore, the secondary instrument error is mainly reflected in its stability to external conditions, sampling speed, measurement accuracy and data processing program, including sensor bridge power supply and sensor output signal transmission

4 conclusion

the market sales of the track will exceed US00 billion yuan in the next 20 years. The track scale operators should timely feed back the operation status of the dynamic track scale and the problems in on-site use to the manufacturers, so that they can timely adopt new technologies and equipment according to the on-site requirements, and produce a new generation of dynamic weighing electronic system with high accuracy and stable performance, In order to meet the needs of the production site to ensure the concentricity of the experiment and meet the measurement requirements of users. At the same time, our users should also constantly improve their own application technology level, strengthen on-site management, and jointly eliminate the factors that cause the measurement error of the track scale and affect its stability one by one

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