The Digital Capacitor Instrument Used For Measuring The Pressure (the Differential Pressure)

The appearance of fieldbus control system makes the field instrument face a new change.Firstly , the paper introduces the background of the project, then the work principle, study status of the capacitor DPT(differential pressure transmitters) are presented briefly, and then analyses WorldFIP protocol in detail, explains the technical characteristics and the main developing tools.Secondly , I discuss the detecting method of the exiguity capacitance, and introduce the principle of the compensating for the temperature.And then, I dissertate in detail the hardware design and the implementation of the meter including electrical source module, data module , double CPU module, fieldbus communication module .Finally , the paper introduces the development of the software , the whole working process of the meter is described in detail. At last, it recommends the advanced view of the research task.