Live Demonstration: a CMOS ASIC for Precise - SiPS - INESC-ID

Live Demonstration: A CMOS ASIC for Precise Reading of a Magnetoresistive
Sensor Array for NDT
Diogo M. CAETANO1, Moisés PIEDADE1, João GRAÇA1,
1
INESC-ID
Rua Alves Redol, 9, 1000-029 Lisboa, Portugal
e-mails: {diogo.caetano, msp}@inesc-id.pt:
[email protected].
Jorge FERNANDES1,2, Luís ROSADO1,2 Tiago COSTA1,2
2
Instituto Superior Técnico, Universidade de Lisboa
Rua Alves Redol, 9, 1000-029 Lisboa, Portugal
e-mails: [email protected]:
[email protected]: [email protected].
Abstract — Non-destructive testing (NDT) based on eddy
currents (EC) is commonly used to detect defects in conductive
materials. Usually the system includes an emitter coil, and one
receiver coil or one Magnetoresistive (MR) sensor. In this work
we added an interface ASIC that pre-amplifies and filters the
signal from an array of MR sensors. This demo will present a
new version based on the work presented at the ECNDT 2014
conference with a paper entitled “A CMOS ASIC for Precise
Reading of a Magnetoresistive Sensor Array for NDT”. Since this
is an on-going work, improvements have been made, namely the
reduction of the system thermal noise to 30 nV/√Hz, the
development of a multigain amplifier and the application of the
same concept and circuit to a multichannel parallel signal
acquisition system. Detection of surface and buried defects will be
demonstrated in different material mock-ups.
III.
USER EXPIRIENCE
The visitor will be able to suggest changes in the test setup
definitions (e.g. inspection speed, displayed information,
mock-up choice) and manually analyse the probe itself which
will be available for interaction. Questions can be asked and
will be thoroughly answered both concerning the integrated
and discrete electronics and the signal processing work.
Keywords — signal processing, eddy current testing (ECT),
NDT-wide, ASIC, CMOS, Magnetoresistive sensor, array.
I.
INTRODUCTION
The scope of this work developed in project IMAGIC [1] is to
develop integrated circuits that will take full advantage of the
MR sensors characteristics and capabilities [2] in a practical
NDT EC based probe [3]. Using an ultra low noise current
source [4], an ultra low noise amplifier with multiple gains
and a eletrical signal cancelation system [5]. With the purpose
of detecting defects behond the state of the art equipment used
in industrial NDT systems.
II.
DEMONSTRATION SETUP
The demonstration includes the live detection of buried
and surface defects in the provided mock-ups and a 2D
reconstruction of the mock-up with the defects highlighted,
similar to the results presented in Figure 1.
Figure 2: Experimental Setup.
IV.
ACKNOWLADGMENTS
This work was supported by national funds through
Fundação para a Ciência e a Tecnologia (FCT) with references
UID/CEC/50021/2013
and
EXCL/EEI-ELC/0261/2012
(Project Disruptive) and the European project FP7-ICT-2011-7
(IMAGIC-GA288381).
The authors also want to thank all the IMAGIC project
partners for their help and fruitful suggestions.
REFERENCES
[1] IMAGIC. IMAGIC European project FP7-ICT-2011-7 (IMAGICGA288381), [Online] http://www.imagic-project.eu/.
[2] P. Freitas, S. Cardoso, R. Ferreira, and F. Cardoso, "Magnetoresistive
sensors," Journal of Physics: Condensed Matter, 2007.
[3] B. Raj, T. Jayakumar, and M. Thavasimuthu, "Practical Non-destructive
Testing," woodhead Publishing , 2002.
[4] T. Costa, M. Piedade, and M. Santos, "An ultra-low noise current source
for magnetoresistive biosensors biasing," in BioCAS, 2012, pp. 73-76.
[5] D. Caetano, M. Piedade, J. Fernandes, T. Costa, J. Graça and L. Rosado.,
Figure 1: Buried defects in aluminium mock-up (deepest defect 9 mm on
the top left, shallowest defect 0.82 mm bottom right).
"A CMOS ASIC for Precise Reading of a Magnetoresistive Sensor Array
for NDT," ECNDT , 2014.
For the demonstration we will be bringing an XY table
developed in-house, with a step motor, the laptop to control the
experiment and show the results, three signal generators and a
lock-in amplifier to simulate the industrial measurement
system [6] (Figure 2).
978-1-4799-8391-9/15/$31.00 ©2015 IEEE
[6] L. Rosado, T. Santos, M. Piedade, P. Ramos, and P. Vilaça, "Advanced
1906
techniques for non-destructive testing of friction stir welding of metals,"
Measurement, vol. 43, pp. 1021-1030, 2010.