The Design And Research For Test System Of Gas-sensor

With the rapid development of the science technology, enlargement of the industry production, and the increasing of the sorts of the production, the condition in which we use gases as the raw material or fuel is increasing, so that the sorts and the quantity of gas produced are increasing too. Most of these gases such as hydrogen, oxygen, etc are flammable and volatile, and some of them are poisonous. So the air will be polluted if these gases leak out into air during their usage or transportation, and even more it will cause fire, blast or casualty when the condition is very serious. Presently, with the improvement of our life level, coal gas and liquefied petroleum gas (LPG) are widespread as house fuels. Once these gas fuel leak out because the pipeline or valve are not good airproof, it will cause poisoning when the affair is not serious, and terrible fire when serious. All these will bring great damage to the security of our life and possession. So it is very important for us to inspect and control these gases well. And it is obviously very important to study on the inspection methods and sensors of all kinds of gases Every characteristic parameter of gas sensors must be tested at the beginning of its manufacture and before its leaving factory. The traditional test methods still take dominant place in all test methods. With the advancement of the human being and the improvement of the life quality, people's gradually increasing consciousness of environment protection and security accelerates the study and the development of the gas sensors. However, the corresponding traditional test methods of the gas sensors are not suit for the request of the times.In this paper, we study mainly on the semiconductor gas sensitive components, and discuss the research and design of the gas sensors test system based on virtual instrument and MPU technology, and at last supply a set test system composed with the simulation of gas sensitive components workspace, signal processor, data acquisition, and data analysis and control.This system is composed with two parts: client and server. And the component test box (client) mainly includes component plate and MPU system. This test box can be made of Plexiglas or stainless steer. In this box there are power supply set, gas injection set, rate of flow test set, circuit plate test set, ventilation set and density and temperature test circuit etc. So it can simulate all the situations of the gas sensitive components' workspace very well. The gas is injected from the gas injection pipeline to the component box and we use the rate of flow test set to control the gas density in the rough.When the injected gas's density is different, the resistance value of the detected component will change accordingly. The output signal denoting this change and some characteristic parameters are sent to MCU system.This MCU system is composed with work power supply, modulation module, switch circuit, encoder, A/D converter, keyboard, display and MCU etc, and it can achieve the data's acquisition and simple process. In order to simulate a better workspace of the gas sensitive component, we test a lot of pots' temperature; and in order to test more exactly the density of the gas in the component box, we add a gas density test circuit in the box.The data of these parameters is processed by the MCU and then are sent to the display, meanwhile it is stored and sent to the server through interface. After the gas sensitive component test software in the client PC is started, the client can receive different sampling data of different gas density, then processes the data accordingly. At last accomplish data expiry's judge, files' classification, data control etc.We expounds concisely the correlative principle and the design in this paper.