| With the development of microelectronics and MEMS technology, it is possible to manufacture micro-hotplate-based gas pressure sensor with the advantages of small size, lightweight, low power, fast response, and easily integrated with IC. In domestic domain, the study on semiconductor solid pressure sensor is very comprehensive, but on gas pressure sensor with micro-hotplate (MHP) is very elementary. Test on the characteristics of the sensor is so important in the study of such kind of micro sensors.In the thesis, the structure of MHP-based gas pressure sensor is introduced firstly. The sensor thermal characteristics are analyed. Four test methods including constant voltage, constant current, constant power and constant temperature are designed, and the sensor response characteristics are analyzed theoretically with them. Then an instrument based on ARM for testing the sensor is developed. The design procedure of the instrument is investigated in detail, including requirement analysis, the partition of function modules, and the design of hardware and software.Hardware of the testing instrument consists of S3C44B0X process unit, ADC unit, DAC unit, analog signals process unit, instrument box and other I/O interfaces. As for software, the real time operating system μC/OS-II is adopted, which is a multitask core and can organize all of the system hardware resources to operate harmoniously, improve real time and reliability of the test system. μC/GUI is used for wave display so that user can observe the gas pressure wave trend. In addition, the system extended some useful functions such as communicating with main computer, alarm automatically, control-signal output and gas pressure analog output, etc.The work in this thesis establishes some foundation for industrialization of the MHP-based gas pressure sensor in the future. The test results indicate that all the parameters and functions of the system satisfied the design requirement. |
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