How To Measure - DeFelsko PosiTector UTG Guide Rapide

The PosiTector UTG M and UTG P in multiple-echo mode
determines thickness by measuring the time between at least
three consecutive back wall echoes.
Probe
In the figure above, multiple-echo mode measures only the time
between echoes. Regardless of whether the steel is coated or not,
all times between echoes are the same. In multiple-echo mode the
gage determines thickness by measuring
six and then multiplying by the velocity of sound for that material.
The resultant thickness calculation made by the instrument is
therefore an accurate measurement of the steel thickness only,
disregarding the coating thickness.
PosiTector UTG P (Precision) probes automatically switch
between multiple echo and single echo operation depending upon
the type and thickness of the material being measured.
The velocity of sound is expressed in inches per microsecond or
meters per second. It is different for all materials. For example,
sound travels through steel faster (~0.233 in/µs) than it travels
through plastic (~0.086 in/µs).
1. Remove rubber cap from probe.
Couplant (glycol gel - included) must
be applied to the surface to be tested to
eliminate air gaps between the wear face
and the surface. A single drop of couplant is
sufficient when taking a spot measurement.
t
t
1
2 3

How to Measure

Figure 2
4
t t
1
2
t t t
+ + , dividing it by
1 2 3
3