ADWEL WTD-501, Operating Manual, Page: 18 / 57

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3.3 CALIBRATION REFERENCES
To perform wedge tightness testing, the WTD needs examples of a tight wedge and a loose
wedge in order to set the appropriate data analysis and processing parameters. These
calibration references are stored in a calibration file and may be created in one of three ways:
Generated, Calculated, or Extracted.
Before WTD testing, for display of RTI during the test, the operator can select three
Calibration modes –
Predefined, Generate, or Floating. If Generate is selected, the operator
is expected to generate the calibration file as a part of the test setup. Floating Calibration ,
allows the computer to search all wedge data from a generator during the test to set the
tightness and loosest limits. In
Predefined Mode , the operator can select a calibration file
already created. (Calculated, Extracted, or Generated)
The default file for
Floating Calibration is ADWELFLO.CAL , but the user can select or
create another file to use. The first tested wedge will be compared against the values from
calibration file. As soon as a looser wedge than the “loosest,” or tighter than “tightest” is
found, this value will become the new default for that end of the tightest range, and all
wedges will subsequently be compared against that tightness value. The default file for
Predefined Calibration is ADWELPRE.CAL .
When selecting
Generated Calibration from the Calibration Menu (part of the test set-up)
the user inputs a name for the calibration file. This file will be used as the calibration file
for display of Relative Tightness Index (RTI) during this test. The RTI (numbers from
0-100) displayed during the test is based on comparison of a wedge test data with
references for Tight and Loose, coming from the calibration file. If, for example, all
wedges during the test are tighter than selected reference for Tight, RTI for all wedges
will be 100. After the test, operator can select other calibration file for data display,
providing better resolution of RTI.
The calibration verification program compares data in the calibration files with original
default values, and then informs the user that the calibration data is good, suspect, very
suspect or invalid.