Optimization And Modularization Of ERT Data Acquisition System

Electrical resistance tomography (ERT) is one of the embranchments of Process Tomography. It is one kind of simplified form of electrical impedance tomography (EIT). ERT has advantages of being non-intrusive, non-radiate and on-line visual monitoring. Many applications of ERT have been found in geoexploration, monitoring of industrial processes and environmental areas.Two/multi-phase flow has a high speed in practical industrial circumstance. It is difficult for existing ERT system to measure two/multi-phase flow which has so high speed in industry. Much practical work need to be done to solve this problem. Now, the real-time performance of TERT-4 ERT system designed by Tomography Group in Tianjin University is not very good, and the data auqatistion speed is about 50 frames every second, and it can not meet the need of prccess measurement. And because the design structure is separated electric circuit design structure, the circuit is instable, and it need debug repeatedly, and there are many difficults in experiment. This paper will solve the slow dada acquisition speed, bad stability and bad reliability in TERT-4 ERT system and the model design of ERT data acquisition system has been finished.The achievements in the thesis are as followed:1. The ERT data acquisition system based on high speed digital I/O card and high speed A/D convert card has been designed. High speed digital I/O card and high speed A/D convert card are used as the control channel and data acquisition channel in data acquisition system respectively. A hardware platform of ERT system is realized. The system consists of exciting signal source module, signal generator module, data processing module, and data acquisition module as well as signal backboard. The system is self-defined bus, using modulation design.2. A program written by C++ is achieved. Generating wavestyle, controlling the electrode choice, setting the amplifying multiple and A/D conversion are all controlled by programs. Every module as well as the whole system is debugged. The function and performance of every module is testing and verifying, including the stability of the signals, the realibility of the band-pass filter, the realibility of the Voltage Controlled Current Source, the feasibility and the validity of the electrode choice, and so on. 3. After the system has been debugged successfully, brine has been immited to the pipe with 16 eletrodes distriuted in a section, and then the static model field experiment has been done, Including single media field and different meida field. And the data has been analyzed simply, the voltage distribution has been deduced, and the stability and the reability of the syetem have been verified.