| The project aimed at developing a flow characteristics test equipment ofelectronic expansion valve for industrial which can accurately measure the flowcharacteristics of electronic expansion valve and automatically determine itseligibility.In this paper, a detailed analysis of the problems of current EXV flow testingequipment were presented, including low automation, low/unreliable test result andconsistency etc. Current research status concerning the development of EXV flowtesting were reviewed, which showed that the development of EXV flowcharacteristic test device was of great significance to China’s cooling equipmentmarket.Secondly, The paper further described the overall design concept, the hardwarearchitecture and software design of the flow characteristics test equipment. Then, theauthor proposed the flowchart of EXV flow characteristic test device. The equipmentis composed of an industrial computer, data acquisition cards, EXV driver and gaspath. The system software was designed under Visual Basic6.0environment and auser-friendly man-machine interface was designed.Then, the EXV drive were described in detail which used micro-controller basedon PIC24family, including the power supply module, central processing module, thedrive voltage regulator module, and communication module.Finally, analysis on the factors which impact the accuracy of EXV flowcharacteristic test device were given. Test gas station has been improved Through theanalysis, a BP neural network model for flow correction was proposed in order toremove systematic errors and improve the measurement accuracy. Temperature,pressure, and pressure were used as inputs of the neural network and the standardvalve flow was used as output. The predicted values were then compared with the realoutput to evaluate the performance of the neural network. The result showed that thedeveloped neural network successfully increased the test accuracy, i.e., from2%towithin1.5%, which well satisfied the design requirements. |
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