Research On Electrical Resistance Tomograghy System Based On DSP

Electrical resistance tomography (ERT) is one of the embranchments of Progress Tomography. It is a kind of simplified form of Electrical impedance tomography (EIT). ERT has advantages of being non-intrusive, non-radiate and on-line visual monitoring. More suitable 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.The dissertation starts with improving the real-time performance of ERT system and puts emphasis on the design of the ERT system. The main research result is as follows: 1.The real-time performance of ERT system is analyzed. Through the research on the each part's response time of data acquisition channel, the analysis of the real-time performance of data acquire system (DAS) is achieved. Based on the academic calculation of time performance of the filter part and the emulation employed to validate the result, a new design scheme of DAS is put forward.2.A hardware platform of ERT system is realized. Based on the analysis of real-time performance of the system, an ERT system, in which the DSP is used as the control and data processing core and the CPLD is used to implement the logic function, is designed. The system consists of the exciting signal source module, the sensor and its select logic module, DAS module, data processing module, logic and time module and the baseboard. The design adopts the user-defined bus and the module structure. In debugging, the ERT system is connected to PC through JTAG interface, so downloading and debugging the program become simple and convenient. The control logic of the system can be in system programmable and the delay time can be controlled accurately.3. According to different frequency of the exciting signal and different conversion rate of Analog to Digital, three methods to obtain the peak value measurement, adapting to direct data conversion, are put forward. Thereby the peak value measurement of signal frequency is achieved under different circumstances.