Software System for Measurement and Processing

1
Software System for Measurement and Processing
Andres Gaviria, Sanichiro Yoshida , Luke
Woodside, Chris Leblanc (From National
Instruments)
2
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.
3
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.
4
To achieve this goal we use an interferometer
configuration as show below
5
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.
6
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.
7
A PC turn into a VI
8
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

9
USER INTERFACE
10
Source code initialization stage for
temperature acquisition
11
Source code Temperature acquisition stage
12
Outputs of the VI
13
Software Tools to analyze fringes
14
Representation of fringe patterns and
quantification of shift displacement
15
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
16
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
17
Conclusions
For the purpose of our experiment the creation of
a VI was a necessity
We successfully develop this VI to support Lukes
Woodside experiment
Future plans
We will expand the System to Synchronize the
process from a single machine
18
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.
19
Conclusions
For the purpose of our experiment the creation of
a VI was a necessity
We successfully develop this VI to support Lukes
Woodside experiment
Future plans
We will expand the System to Synchronize the
process from a single machine