Study Of Testing System For Gas Sensors Based On The Printer-port Of PC

Identifying the main parameters of gas sensors is of great significance to their theoretical research and application.Based on the testing norms of gas sensor,this paper studied testing technology of gas sensor,discussed detailedly how to control the working environment temperature of gas sensor,collocate gas and collect data,and discussed the structure of testing system of gas sensors.This paper put forward a testing method for gas sensors by achieving the signal control and data transmission between the computer and peripheral circuit via the printer-port.By dividing the testing system into three pares,namely,temperature control system,data acquisition system and gas collocating system,this paper discussed the PID function to control temperature,the A/D function to gain information of parameters of gas sensors,the D/A function to set the flow of gas,realization of the control circuits of mass flow controller(MFC) and electromagnetic valve,the anti-jamming measures for hardware circuits,etc..In the software of testing system,this paper divided it into modules,adopted standard menu form,and discussed how to design the program to open files and close files,the program to collect data and display them,the program to clean up gas impurity before gas-in,the program of gas-in,the program to clean up the pipes after experiment,etc..With the specific hardware circuits,this paper used the Visual C++6.0 to develop application program based on the printer-port.Finally,this paper analyzed the accuracy of the main modules firstly,and then tested the standard commercial gas sensors and the gas sensors we developed in our laboratory by using the testing system,and discussed and analyzed the testing results.These all are of instructional significance to how to use the testing system.