System Design for the Control of a Tomography Instrument via an IP link

E.W. Randall1 , T.M. Long2, J. Salkinder2

1 Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa, E-mail: E.W. Randall: bill.randall@uct.ac.za

2 Department of Electrical Engineering, University of Cape Town

ABSTRACT

Current tomography instrumentation is typically linked to a PC for data acquisition, storage and performing the image reconstructions. An application program specific to the instrument is written to perform these functions and does generally not allow external end user written software to interact with it. The approach adopted in this work is to provide a mechanism for a Matlab (or other) “front end” to control the instrument, either on the same PC or on a remote system linked by an Ethernet network using IP protocols. Interaction with the instrument is by means of a specially developed set of Matlab functions. Various hardware configurations are investigated. These include providing the PC server functionality by embedding a small form factor PC system in the tomography instrument. The front-end Matlab code, which may be modified by the end user, can acquire data from the instrument and call EIDORS functions to perform image reconstruction. In addition, the system provides a method for the implementation of feedback control of a process. This paper describes the communications techniques used and the functions implemented for data acquisition and control. An example application demonstrates the functionality of the system.

Keywords Tomography, ERT, Ethernet, TCP/IP, networks, control, EIDORS