DeFelsko PosiTector UTG Notice D'instruction page 8

2. Place the probe flat on the surface. Use moderate pressure to
press against the top of the probe with a thumb or index
finger when measuring with cabled probes.
When the probe senses echoed ultrasound, a coupled symbol
will appear and thickness values will be displayed. While the
probe is coupled, the PosiTector UTG continually updates the
display. The Gage will emit a "tick" sound every time the probe
takes a measurement. The Reading Tick option can be disabled
in the Setup menu (see pg. 11).
3. When the probe is removed from the surface, the last
measurement will remain on the display.
Occasionally, excess couplant will remain on the probe when the
probe is lifted from the surface. This may cause the PosiTector
UTG to display a final measurement value different from those
observed when the probe was on the surface.
Discard this value using the
measurement.
Ultrasonic measurements are affected by the condition,
roughness, and contour of the surface to be tested.
Measurement results may vary on coarse surfaces. Where
possible, it is recommended to seat the transducer on a smooth
flat surface that is parallel to the opposite side of the material.
On rough surfaces, the use of a generous amount of couplant
minimizes the surface effects and serves to protect the transducer
from wear, particularly when dragging the probe across a surface.
NOTE:
On smooth, uncoated metal surfaces PosiTector UTG M
and UTG P probes (in multiple-echo mode) may occasionally be
unable to give a measurement result even when the "coupled"
symbol appears. Use additional couplant and lighter pressure on
the probe when measuring.
Alternatively, laying a plastic shim on the surface with couplant
applied to both sides to simulate a painted surface will help
produce a steel-only thickness measurement (multiple-echo
Surface Conditions
6
button and repeat the