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					   Software System for
Measurement and Processing

   Andres Gaviria, Sanichiro Yoshida ,
           Luke Woodside,
Chris Leblanc (From National Instruments)
Measurement becomes often a challenge
in a Physics Research Lab
Theoretical advances require complex
experiments to make increasingly subtle
observations
Researchers conceive clever experiments
to inquire nature yet conventional
instruments offers limited capabilities to
properly measure selected variables.
In our lab a setup was conceive to measure
the correlation between index of refraction
and the concentration of a solution
Results from this Measurement appeared
to be biased by the effect of Temperature

To correct this problem we had to establish
first a correlation between index of
refraction and temperature.
To achieve this goal we use an
interferometer configuration as show below:
The challenge : simultaneously keep
track of temperature readings and fringe
patterns.
For each temperature reading we must
keep track of a corresponding fringe
pattern
The problem: No single instrument exists
on the market capable to perform such
measurement.
Companies like National Instruments
had being offering alternatives to
conventional instrumentation for more
than a decade.
The solution is to develop a Virtual
Instrument also known as VI.
A VI is a computer program written in
LabView.
LabView is an environment that
enables to turn a PC into a general
purpose instrument.
A PC turn into a VI
   What does the VI for you ?
• A VI is designed to acquire and store
  several kinds of data in a synchronize way
• A VI also process raw data to generate
  meaningful reports
• Uses the computer speed and innate
  advantages to perform repetitive task
USER INTERFACE
Source code : initialization stage for
     temperature acquisition
Source code : Temperature acquisition stage
Outputs of the VI
Software Tools to analyze fringes
Representation of fringe patterns and
quantification of shift displacement
IF the task of reading temperatures
and taking fringe pictures was made by
human operator this will happen:
It takes 2 minutes to acquire a set of
meaningful data. In that time span 2
human operators will acquire at the most
a picture and a temperature reading
every 10 seconds for a total of 12
pictures and 12 temperature readings
 With the VI we achieve sample rates up
 to 4 pictures and 4 data readings every
 second.
 In 2 minutes we can acquire up to 480
 temperature readings and 480 pictures.
 A fringe shift cycle occurs with a
 frequency greater than 1 Hz
Only the resolution provide by the VI
enables to take appropriate measurements
  Conclusions:

For the purpose of our experiment the
creation of a VI was a necessity
We successfully develop this VI to
support Luke’s Woodside experiment
Future plans:
We will expand the System to
Synchronize the process from a single
machine
Future plans:

We will expand the System to
Synchronize the process from a single
machine

We will add processing capabilities to
the VI to generate report that will covert
must of the offline analysis that we
currently do.
  Conclusions:

For the purpose of our experiment the
creation of a VI was a necessity
We successfully develop this VI to
support Luke’s Woodside experiment
Future plans:
We will expand the System to
Synchronize the process from a single
machine

				
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posted:7/15/2013
language:English
pages:19