phase II+ UTG-400, Manual, Page: 6 / 22

3. MEASURING THICKNESS
3.1
Sound Velocity Calibration
In order for the gauge to make accurate measurements, it must be set to the correct sound velocity for the
material being measured. Different types of material have different inherent sound velocities. If the gauge is not set to
the correct sound velocity, all of the measurements the gauge makes will be erroneous by some fixed percentage. The
One ‐ Point calibration is the simplest and most commonly used calibration procedure optimizing linearity over large
ranges. The T wo ‐ point calibration allows for greater accuracy over small ranges by calculating the probe zero and
velocity.
Note : One and Two point calibrations must be performed on material with the paint or coating removed. Failure to
remove the paint or coating prior to calibration will result in a multi material velocity calculation that may be different
from the actual material velocity intended to be measured.
Calibration to a known thickness
Note: This procedure requires a sample piece of the specific material to be measured with a known thickness
value. This part should be measured with a caliper or micrometer.
1)
Perform a test on the built‐in test block to verify unit is functioning properly
2) Apply couplant to your sample piece.
3) Press the transducer against your sample piece, making sure that the transducer sits flat against the surface
of the sample. The display should show a “white colored” thickness value.
4) Having achieved a stable reading, remove the transducer. If the displayed thickness changes from the value
shown while the transducer was coupled, repeat step 3.
5) Press the CAL/ON button to enter Calibration mode. On the bottom left corner of the display it will show VEL.
Press the virtual P1 button to enter velocity setting.
6) Press the transducer against the sample piece, making sure that the transducer sits flat against the surface of
the sample. The display should show some thickness value in the Top Left Corner as T= X.XXX.
7) While holding the probe on your sample, use the 4‐Arrow buttons to change the velocity value until you see
the T= the actual thickness of your part.
8) Press P2(Done) button to save the setting.
9) You can now begin testing your application(s) of this same material.
3.2. Adjust the velocity directly if the material velocity is known. See illustration below.