Research On Communication Method Of Electrical Resistance Tomography System Based On USB Technique

Process tomography (PT) can provide two/three dimension information related to the interior behavior of medium within the process equipments, such as close pipes, vessels and so on, in real time. This gives a novel approach for two-phase flow parameter measurement. Electrical resistance tomography (ERT) is a kind of PT based on the theory of electromagnetic field and principle of electrical sensitivity. ERT has advantages of being visual, non-intrusive, non-radiate and low in cost. It has an extensive application prospect in industrial process.ERT has gradually got applications in practical industrial process in recent years. With the requirement of industrial field and the development of ERT,ERT system has been required to be a kind of intelligent and visual portable measuring instrument for two-phase flow. This dissertation makes research on the communication method of ERT system based on USB and preliminarily discusses the scheme of portable ERT measuring instrument.The specific work that the author has finished in this research is as follows:1. Based on the analysis of data amount of ERT system communication module, the existing communication methods of peripheral equipment of PC are compared. An idea is put forward that USB is employed to implement the communication between PC and ERT system. A new communication module of ERT system employing USB technique is developed to carry out the communication between PC and ERT system based on DSP. It solves the ever problems of not being portable and data transmission bottleneck. Furthermore it has positive effect on improving the real-time performance of ERT system in two-phase flow on-line measurement application.2. Based on USB, two schemes of ERT system are brought forward. In the first scheme a microcontroller is used to control system and DSP is employed to process data, while in the second DSP + CPLD(Complex Programmable Logic Device) are used to control system and DSP is employed to process data. The system function,development period as well as cost are compared between the two schemes. 3. The control module of ERT system based on the microcontroller PIC16F877 is designed and implemented preliminarily. The feasibility of the scheme of portable ERT measuring instrument is made primary study of. This lays the foundation for the development of portable ERT measuring instrument.