Name: Andrea Borsic

Email: aborsic@brookes.ac.uk

CompanyName: Oxford Brookes University

Country: UK

Abstract:

OXBACT 5 Data Acquisition System's software architecture

Andrea Borsic, Christopher N. McLeod, Xicai Yue

We present in this paper a brief overview of the OXBACT V's software architecture. Given the
complexity of modern EIT data acquisition systems, we believe OXBACT V's novel software
architecture to be of scientific interest.

A typical EIT DAS (Data Acquisition System) is composed by a custom data acquisition
subsystem, which can range from a single PCB board to full rack mount system, and by a host PC
that controls the process and logs the data. On simpler systems the controlling software
resides entirely on the host PC side. On more sophisticated instruments, the DAQ (Data
Acquisition) subsystem is based on a DSP or on a microcontroller and part of the software will
reside on it. The development of this low level software is long and error prone, debugging
tools are difficult to use and maintenance is hard.

In order to overcome the limitations of the classic architecture we identified a new structure
that amongst other advantages offers a quicker development process, improved development tools
and better maintenance cycle. We decided to base the custom DAQ subsisted on a Pentium
compatible PC104 board. The presence of a ``traditional" processor in the DAQ subsystem allows
running an embedded real--time OS on it. All the signal processing tasks previously carried
out via DSPs can now be performed by the Pentium processor and be coded in higher level
language for a much quicker development cycle. The presence of an OS and of standardised
hardware components allows us to connect the DAQ subsystem to the data logging PC via
traditional network solutions (Ethernet, Wireless Ethernet) and to develop all the
communications tasks on top of the TCP/IP protocol. Several other details of interest will be
presented, including the use of MATLAB for direct control of the instrument and data
acquisition tasks.

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