A Parallel Data Acquisition System based on CPCI for ERT

Cong Xu, Zhiqiang Zhang, Jun Han, Feng Dong

Tianjin Key Laboratory of Process Measurement and Control, School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, P.R. China

Tel: 86­22­27890276, Fax: 86­22­27892055, Email: fdong@tju.edu.cn

ABSTRACT

Electrical resistance tomography (ERT) is to achieve visual detection through boundary sensors array to obtain the real­time distribution of the sensing field. As a non­radiant and unperturbed 2D/3D boundary technique, ERT has wide application prospect in petroleum and chemical industrial processes with conductive continuous phase flow. For obtaining accurate information reflecting the sensing field, many data acquisition systems have been developed for on­line measurement.

To better satisfy industrial requirements, ERT is presently expected to be more flexible, applicable and easier to extend. For this purpose, a system based on industrial bus standard is designed as a 16­channel parallel data acquisition system, where FPGA and Compact PCI are adopted as the core components. FPGA is configured with logic control and basic algorithm’s implementation (including digital FIR filter and digital demodulation). Compact PCI, with identical electrical function with PCI but enhanced mechanic structure and hot­plugging feature, is employed for high­speed data­transmission. Dedicated software with a user­friendly interface has been developed to configure the signal generator and data transmission.

Preliminary static experiments using this system have been done, and the results show that the data acquisition system works properly with SNR above 54dB, and the data acquisition rate of this ERT system could reach almost 1400 frames per second without affecting the performance.

Keywords Electrical resistance tomography; Data acquisition; Compact PCI; FPGA; Digital filter; Digital demodulation