Research On ECT Data Acquisition System Based C8051F700

Electrical Capacitance Tomography (ECT) technology is one kind of processtomography technology based on the principle of capacitance sensitive. Its basic principleis that through the capacitor plates uniformly attached to the pipe outer wall, ECT systeminducts the change of capacitance value in the measured region because of the mediachange in the pipe internal, and sents the measured capacitance value to PC, reconstructsimage by the image reconstruction algorithm, thereby obtaining the distribution of themedium within the measured region. It belongs to the non-contact, non-injury detectionmethod. it has been broad prospect for industrial applications because of its simplestructure, low cost, fast response, etc. This paper briefly introduces the principle ofelectrical capacitance tomography technique, summarizes the research status of ECT athome and abroad, compares the traditional capacitance measurement method by discretecomponents and the new capacitance measurement method by integrated chip, analysis theadvantage of the CDC (Capacitance to Digital Converter) technology in capacitancemeasurement, and focuses on the realization of the hardware and software of ECT system.This system uses the upper and lower machine parallel working ways: use C8051F700microcontroller built-in16-bit capacitive digital converter subsystem to establish Lowermachine of ECT system, Lower machine includes extremely plate capacitor input circuit,power supply circuit, LED display circuit and RS-232communication interface circuit.C8051F700contains32capacitance input channels, multiple capacitance values scanmeasurement can be achieved through a multiplexer. Lower machine completes dataacquisition function and data transmission function. PC Software based on LabVIEW is animportant part of controlling system operation, completes communication with Lowermachine, controls capacitor acquisition method, it achieves data receiving, data processing,image reconstruction and three-dimensional image display functions. Human-computerinteraction interface is concise and beautiful.On the condition of lab, the stability and linearity of Lower machine is tested, the function of PC Software is tested. The experiment results indicate that the system couldcomplete multi-channels capacitance value measurement, has certain stability andlinearity, use PC Software that is programmed by LabVIEW to achieve to reconstruct anddisplay2D/3D image.