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7.3.3 Known Material Calibration
If the material velocity is unknown, and a sample thickness cannot be taken from the material, you
can choose a material type from a list stored in the gauge. For each material stored in the list there
is a corresponding velocity value.
Note: These velocities will not always be an exact representation of the material being tested. Use
these values only if a close approximation is acceptable.
1. Press
, scroll to the CAL menu and then highlight the MATERIAL function.
2. Press
to display the list of material types.
3. Scroll through the material list until the appropriate material is highlighted.
4. Press
to choose the material type.
5. Press
to select the material type and display the menu items with the new material type
selected
6. Press
to return to the measurement screen.
8 MEASUREMENT - TAKING READINGS
Disclaimer: Inherent in ultrasonic thickness measurement is the possibility that the instrument will
use the second rather than the first echo from the back surface of the material being measured. This
may result in a thickness reading that is TWICE what it should be.
Responsibility for proper use of the instrument and recognition of this phenomenon rests solely with
the user of the instrument.
Other errors may occur from measuring coated materials where the coating is insufficiently bonded
to the material surface. Irregular and inaccurate readings may result. Again, the user is responsible
for proper use and interpretation of the measurements acquired.
8.1 Before you start
•
Prepare the surface, see "Condition and Preparation of Surfaces" on page 33.
•
Ensure the correct transducer is selected and set in the gauge, see "Transducer - Setting Type
Of" on page 9.
•
Select the correct measurement mode (P-E GT, E-E).
•
Set the zero point of the transducer, see "Transducer - Zeroing" on page 10.
•
Calibrate the gauge, see "Calibrating" on page 11.
•
Choose the measurement view (DIGITS or B-SCAN), see "The Measurement Screen" on
page 7.
8.2 Procedure
1. Apply couplant
For the gauge to work correctly there must be no air gap between the transducer and the
surface of the material to be measured. This is achieved using a couplant.
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