Development On The Pneumatic-Electric Transducer Based On The Silicon Pressure Sensor

Pneumatic-measuring instruments are widely used in the dimension measurement and the inspection of machine parts for pneumatic-measuring technique's high accuracy, non-contact measuring method and simple structure. Especially, the pneumatic–measuring technique has a special priority on measuring inner and outer diameter of some thin wall parts and soft material parts, such as inner diameter of deep hole and small hole as well as narrow groove breadth which are measured difficultly by mechanical gauges and instruments.With the rapid development of electronic and information technique, manufacture automation is made great progress. The general pneumatic-measuring instruments (such as the buoy pneumatic-measuring instruments) will be replaced by the new type pneumatic-electric measuring instruments. And the pneumatic-electric measuring instruments will greatly promote the development of machine manufacture automatic measurement and inspection because of its electrical characteristics. In this paper, basic pneumatic-measuring theory and air circuit system working principle are introduced. The pneumatic-electric transducer employs a MPX5500DP silicon pressure sensor which converts air pressure signal into voltage signal, and displays on the electron column after the signal conditional circuit's processing. It is described from the following aspects. Firstly, a differential pressure air circuit system is employed and designed in this research. And a kind of axial pneumatic probe for testing is designed and made, too.Secondly, the pressure sensor made by Motorola Co. Ltd. in USA is chosen as the key part of the pneumatic-electric transducer.Thirdly, the signal processing system of the pneumatic-electric is developed. There are zero-adjustment, gain-adjustment and switch on-off in it. Fourthly, In order to enlarge the linear measurement range, I study the software linearity.Finally,the micrometer checker is used as a micro-offset measurement unit for experiment. The initial measuring space and better linear range of the...