Measurements Are Made - sauter TU-US Instruction Manual

5.5 Measurements are made

The meter always stores the last measured value until a new value is added.
For the measuring probe to function properly, there must be no air bridges between its
contact surface and the surface of the material to be measured. This is achieved with
the ultrasonic gel, the "coupling agent". This liquid "couples" or transmits the ultrasonic
waves from the measuring probe into the material and back again. Before the
measurement, a little coupling agent should therefore be applied to the surface of the
material to be measured. Afterwards the measuring probe is carefully pressed onto the
material surface. The coupling symbol and a number appear on the display. When the
device has been adjusted and the correct sound velocity has been determined, the
number in the display shows the current material thickness, measured directly under
the measuring probe.
If the coupling indicator does not appear or the number on the display is questionable,
first check that there is sufficient coupling agent at the point under the measuring probe
and that it has been placed flat on the material. Sometimes it is necessary to try a
different measuring probe for the corresponding material (diameter or frequency).
While the measuring probe is in contact with the material to be measured, four
measurements are taken per second. When it is lifted from the surface, the display
shows the last measurement.
Note: Sometimes a thin film of the coupling agent is drawn between the probe and the
material surface when the probe is lifted. In this case it is possible that a measurement
is made through this film, which then turns out larger or smaller than it should. This is
obvious because if one measurement is taken while the measuring probe is still in
place and the other when it has just been lifted off. In addition, when materials with
thick paint or coating are used, it is these rather than the intended material that is
measured instead. Ultimately, the responsibility for the clean use of the measuring
device in connection with the detection of these phenomena is withheld from the user.
14 TU_US-BA-e-2020