Research On Remote-monitoring System For Liquid Level Of Liquid Nitrogen Based On GPRS And Web Technology

Liquid nitrogen is a low temperature liquid. It has a wide range of applications in industrial production and scientific research. Its liquid level may change fast because of its fast evaporation. So it should be detected and added in time to ensure good effect to supply a low temperature circumstance. And remote-monitoring is needed because most of its application scenes are unattended.GPRS technology makes full use of the existing wide coverage of GSM network and has advantages such as good real-time effect, high transfer rate and low operation cost. Its application in remote-monitoring system can make up for the disadvantages of wired communications such as high cost, unconvenient layout, etc. Using Web technology can make it possible for operators to monitor and control remote devices by login the system through common browsers, and make remote-monitoring more convenient.Based on these backgrounds, the research on remote-monitoring system for liquid level of liquid nitrogen based on GPRS and Web technology is conducted.The liquid level detection device is designed based on the negative temperature characteristics of PN junction with low price1N2222transistor. The concentrator constituted by F500SCM and EM310module is responsible for data collection from detection modules and communications with monitoring center.The monitoring center is designed with socket commnication realized by Java for commincation module; MySQL database for data processing and save. Based on JSP+Sevlet+JavaBean develop mode, related Web pages are designed. Operators can use any browser to login the system to monitor and control remote devices.Experimental results show that the system can run reliably and can be used in practical application.