Optimization Design of Electrical Resistance Tomography Data Acquisition System

The process tomography based on electrical sensitive principles is a new technology which aims at section information measurement. Electrical Resistance Tomography is one kind of process tomography which is based on electrical sensitive principle. It has advantages of being non-intrusive, non-radiate, online visual monitoring and low in cost. There are some disadvantages in data acquisition speed, stability and reliability in the existing ERT system. Aiming at these problems, a new ERT data acquisition system based on digital I/O card and A/D conversion card is developed; every other module of the ERT system make an improvement: the system backboard uses an user-defined bus; the sine-wave generator module use a DDS chip to generate signals whose phase, amplitude and frequency can change easily; a multiplication demodulation which can be controlled easily has been used to improve the transition speed. By calculation, the data acquisition speed of the system has been improved. The structure is simple, so the stability and reliability is better than before.