Design Of Electrical Resistance Tomography Based On Parallel Data Acquisition

Two-phase/multiphase flow exists extensively in industrial production. Along with thesocial progress and industrial development, people need to understand more detectionparameters of two-phase/multiphase flow in order to obtain the medium distributioninformation in two-phase/multiphase flow. The electrical resistance tomography technology isa high-tech detection technique for detecting the distribution information oftwo-phase/multiphase. Based on further research on electrical resistance tomography dataacquisition system, the paper puts forward an improved signal amplification mode of dataacquisition system. The main research works in the paper are as follows1. An improved signal amplification mode was proposed. Multi-channel programmablegain amplifier was designed in the signal conditioning circuit. Compared with theconventional fixed-gain circuits and with several gain values for Programmable GainAmplifier chip circuits, the circuit which has 256 adjustable gain values can accuratelymeasure the weak signal to the best conversion level of the ADC chip. To some extent, it canimprove the data collection accuracy for the system.2. Complex Programmable Logic Device (CPLD) was adopted to control two pieces ofADC chip to finish the conversion of multi-channel data acquisition and transmission.Compared to traditional data acquisition system, it has certain advantages in speed by usingthe programmable logic devices to control the ADC. In addition, the CPLD sends thecollecting results to the ARM microcontroller real-timely, which can reduce the processingburden of the ARM microcontroller.3. The 32 bit high performance and low power consumption LPC2366 chip was adoptedto realize each module function, which can enhance the system processing rate to a certainextent. During the data transmission, the LPC2366 chip coming with USB2.0 port transmitthe data to the host computer real-timely. Compared to a separate USB device controller, the LPC2366 chip coming with a USB device controller has good stability and simple designcharacters, which can reduce the system cost.Experimental results show that the parallel data acquisition system of ERT designed bymulti-channel programmable amplification mode can improve the accuracy of the dataacquisition and theoretically achieve a maximum 1250 frames per second of real-timesampling rate. To a certain extent, the designed ERT system increases the data acquisitionaccuracy and sampling rate which achieved the desired results.