An improved design for a Current Pulse Electrical ResistanceTomography System

E.W. Randall1, A.J. Wilkinson2, T.M. Long2, K.E. Duggin2, K. H. Hauslaib2 1 Department of Chemical Engineering, University of Cape Town,

Private Bag, Rondebosch, 7701, South Africa

2 Department of Electrical Engineering, University of Cape Town E­mail: bill.randall@uct.ac.za

ABSTRACT

The design and application of the UCT current pulse Electrical Resistance Tomography (ERT) system has been reported at previous world congresses and in several journal papers. Performance has been shown to be similar to that of other designs. This paper describes the latest circuit implementations which were developed using open­source design tools. The updated instrument incorporates an embedded PC with a wireless LAN connection allowing multiple units to be controlled from a master PC work station.

The instrument configuration presented provides a viable, easy to implement and low cost solution for tomography measurements in systems where the medium under investigation is predominantly resistive. Typical applications are in minerals processing mixing systems, bubble columns, and slurry pipe­line flow measurements. The system can acquire data at a rate of 400 dual frames/second using the adjacent pairs measuring strategy and display 2D reconstructions in real­time at approximately 20 frames/second. The recorded data sets can be used to determine velocity profiles in slurry pipe­lines using cross­correlation techniques.

Although there have been many publications dealing with the design of sensor electronics and associated software we believe that this is the first publication of a complete system in sufficient detail for the various circuit elements to be replicated. The circuit descriptions of the various modules and details of the associated software are likely to be of interest to engineers engaged in the design of electrical tomography instrumentation. The multiplexing hardware and the acquisition software could in many cases be used with other sensor systems.

A web site will be launched to coincide with WCIPT6 which will present further details of the system, its performance and applications. The authors hope that this will stimulate interest in the current pulse technique and promote further development and application of such systems.

Keywords: Electrical Resistance Tomography, ERT, Current pulse, instrumentation