Design Of Digital Intelligent Weighting Transducer Of Resistance Strain Gauge Load Cells

The electronic weighting has more advantage, such as high weighting speed and high weighting accuracy. And it can be easily used. So they were well used in many fields of national economy, and has been taken more and more attention seriously. For different Weighting equipment is used in different environment and has different claimed accuracy, and the sensors were used has not the identical features. How to improve the universality of control circuit and how to avoid that the controller and the sensor must be used one to one has become a very important problem. In regard to this, the author conducted a survey about the use of weighting equipment and consulted a lot of engineering and literature, made a deep research into the above problem.Firstly, the principles of several common load cells were analyzed, their advantages and disadvantages was compared. According to the present situation of the application of various sensors, how to calibrate the characteristic curve of different resistance strain sensors was studied in the paper as a main problem, and the design scheme and specifications was also proposed. Second, the hardware design of the transducer is expounded in detail, which was composed of five parts. They were the study of technology measuring the sensor signal, the design of analog signal and digital signal conversion circuit, the design of processor's interface circuit, the design of the power supply circuit, the design of system's anti-interference. Following, sensors and linear error of measurement circuit were analyzed, and method of the least squares linear correction was used to fit sensors'characteristic curve. Fitted characteristics curve equation had been deduced. The traditional scale transform formula was improved. The compensation measures system zero temperature drift was proposed. Finally, the system's workflow was expounded. The procedure of main interface circuit driver program and the system master program were designed, and their flow charts were given.Test results shown that the nonlinear error of the system is smaller than the traditional method of correction. Zero temperature drift is also comparatively very smaller. The stability is better after it worked for a long time. The desired goal of the weighting transducer had been achieved.