FUTEK VCal Sensor Verification - Manual (Page 45)

Futek Advanced Sensor Technology – Futek VCal™Documentation Rev. 1.8.0 07/26/05
©Futek Advanced Sensor Technology 2005 45
Signature Test
In this type of calibration you are given the chance to take advantage of Futek VCal™’s tools for Signature Checking. This tool allows you to
monitor and control the performance of your sensors. Here you can define a Primary ‘signature’ for a sensor; VCal™ will create a profile for
your sensor, recording such characteristics as Output, Non-Linearity, and Hysteresis. Then, you can perform Subsequent tests and match the
characteristics of your Subsequent Test against the Primary Signature Test characteristics. This allows you to track the performance of your
sensor, and allows you to identify non-conforming trends in their earliest stages. This aids in the establishment of performance traceability, and in
the definition of calibration intervals, and gives added assurance in the reliability of your calibration measurement results. If you load a saved test
on the sensor you wish to perform Signature Checking on, and then select Signature Test under the Signing Hand icon pulldown menu, you
will first see the following screen . . .
Here you can see a list of the Signature Test Profile Tests you have
performed on this specific cell. Select all of the tests you wish to compare the
results of.
Under the Comparison section of the pane you can select which output
characteristics of the tests you wish to compare.
Once you have selected which tests you wish to compare, and you have
selected which characteristics of these tests to include in your comparison,
you can press the
Generate Data button to bring up the next screen . . .
Here you can see that I have selected all three saved tests, one Primary (P),
and two Subsequent (S), and that I have chosen Output as my
characteristic to compare.
Then when I pressed Generate Data it brought up the this comparison Grid.
In this Grid VCal™ lists the load points, (which must be same in all tests you
wish to compare), the outputs in all three tests and the percentage of error
between the first and second tests, and the first and the third tests. Had I
chosen Non-Linearity instead of Output in the Comparison area,
the Comparison Grid would have shown the Load points from the three
tests, the the Non-Linearity errors from the three tests, and the percentage
of error between the readings of the tests. Had I chosen Hysteresis the Grid
would have displayed the appropriate hysteresis data.
There is also a button marked Export Data , clicking this will bring up
this Save Text File in Desired Path box; here you can specify where
to save a text version of your test. Just give your test file a name, and
specify where on your hard drive or Removable media to save the file
to, and it may be referenced later for analysis, or performance monitoring
activities.