Research On Design Of A Novel Wireless Intelligent Weighing System

As an important measurement equipment, the weighing system is used widely in the industry, the agriculture, the medical treatment, the transportation and other fields. At the same time, with the rapid development of the intelligent control and wireless communication technology, all areas have more requirements to the weighing system, such as the reliability, the accuracy, the wireless transmission, intelligent function, and others.A novel wireless intelligent weighing system design was proposed. The weighing system consists of the data collection, the analog-digital conversion, the memory module, the wireless transceiver module, the infrared module, the control module and the display module. The wireless transceiver module can transmit the weighing data and monitor the system by wireless. By combining the infrared remote control, the keyboard with the software programming, the functions of the system, such as the information acquisition, the autonomous calibration, the parameter setting and the data storage, are completed. In addition, in order to protect the measurement data when the power was cut off emergency, a power on and off circuit with data protection function was proposed, and the power consumption of the weighing system is reduced effectively.In order to reduce the influence of interference signals to the measuring accuracy of the weighing system in the data collecting, an improved amplitude-limiting and average filtering algorithm was proposed. Being combined the limiting filtering, the median filtering, the moving average filtering, and the non-linear compensation, the improved amplitude-limiting and average filtering algorithm can eliminate the random pulse and suppress the periodic interferences, and can improve obviously the measurement precision of the weighing system.Based on the experiment of eight different targets range from 5kg to 50 kg, the parameters of the system, such as the function, the accuracy, the sensitivity, the repeatability and the hysteresis were measured and analyzed. Experimental results show that the system can realize the information acquisition, the autonomous calibration, the parameter setting and the data storage. The maximum error rate of the weighing systems is about 0.1%, and the accuracy and the stability are very good. In addition, the experiment result shows that the sensitivity is about 0.1mV/kg, and the repetitive error is about 0.32% and the maximum hysteresis reference error is about 0.16%. This shows that the system has a desirable input and output characteristic. Furthermore, the wireless transmission distance is about two hundred meters. The system using and without using the improved amplitude-limiting and average filtering algorithm were measured and analyzed. The result indicates that the maximum error rate of the weighing system using this algorithm fell from 0.9% to 0.1%, and the accuracy of weighing system is nine times higher than that of without using this algorithm. The interference signals are suppressed and the accuracy of the system is improved effectively.