KERN & SOHN TN 300-0.01US - Manual (Page 5)

Sauter GmbH
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D-72336 Balingen
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Internet: www. sauter.eu
Instruction Manual
TN_US
TN_US-BA-e-1112 5
material being measured. Different types of material have
got different inherent sound velocities. If the instrument
isn’t set to the correct sound velocity, all the
measurements will be deficient by some fixed percentage.
The One-point calibration is the simplest and most
commonly used calibration procedure, optimizing linearity
over large ranges.
The Two-point calibration has got higher accuracy over
small ranges by calculating the Zero adjustment and sound
velocity.
Note: One- and Two-point calibrations should only be
performed on material where the paint or the coating is
removed; if not, it will result in a multi material velocity
calculation which is surely deviating from the actual
velocity of the material intended to be measured.
4.3.1 Calibration to a known thickness
1) A Zero adjustment has to be performed.
2) A couplant has to be applied to the sample piece.
3) The transducer has to be pressed against the sample
piece, making sure that the transducer is placed flat on it.
The display now shows any thickness value and the
coupling status indicator should appear steadily.
4) As soon as a stable reading is achieved, the transducer
has to be removed. If the displayed thickness now
distinguishes from the value shown while the transducer
was coupled, step 3 has to be repeated.
5) The key has to be pressed to activate the calibration
mode. The MM (or IN) symbol should start flashing.
6) The and the key has to be used to adjust the
displayed thickness up or down until the thickness of the
sample piece is matched.
7) The key has to be pressed again. The M/S(or IN/µS)
should start flashing. Now the sound velocity value, which
has been calculated based on the thickness value that was
entered, is displayed.
8) The key has to be pressed again to exit the
calibration mode and return to the measurement mode.
The instrument is now ready to perform measurements.
4.3.2 Calibration to a known velocity
Note: This procedure requires that the sound velocity of
the material being measured, is known. A table of the most
common materials and their sound velocities can be found
in Appendix A of this manual.
1) The key is to be pressed to activate the calibration
mode. The MM (or IN) symbol should start flashing.
2) The key is to be pressed again, so that the symbols
M/S (or IN/µS) are flashing.
3) The and the key are to be used to adjust the
sound velocity up and down until it matches the sound
velocity of the material being measured. The key can
also be pressed to switch among the preset, commonly
used velocities.
4) To quit the calibration mode, the key has to be
pressed and the instrument is ready to perform
measurements.
To achieve the most accurate measurement results, it is
generally advisable to calibrate the instrument to a sample
piece of known thickness. The composition of materials
(and thus, its sound velocity) sometimes varies from lot to
lot and from manufacturer to manufacturer.
Calibration to a sample of known thickness ensures that
the instrument is set as closely as possible to the sound
velocity of the material being measured.
4.3.3 Two-point Calibration
Note: This procedure requires that the testing person has
got two known thickness points on the test piece which are
representative of the range being measured.
1) A Zero adjustment has to be performed.
2) A couplant has to be applied to the sample piece.
3) The transducer has to be pressed against the sample
piece at the first / second calibration point. It has to be
made sure that the transducer is placed flat on the surface
of the sample. Now the display should show any (probably
incorrect) thickness value and the coupling status indicator
should appear steadily.
4) As soon as a stable measurement is achieved, the
transducer is to be removed. If the displayed thickness
distinguishes from the value shown while the transducer
was coupled, step 3 is to be repeated.
5) The key is to be pressed. The MM (or IN) symbol
should start flashing.
6) The and the key are to be used to adjust the
sound velocity up and down until it matches the sound
velocity of the sample piece.
7) The key has to be pressed. 1OF2 will be shown on
the display. Steps 3 to 6 are to be repeated on the second
calibration point.
8) The key has to be pressed, so that the symbol M/S
(or IN/µS) is flashing. The sound velocity value, which was
calculated based on the thickness values being entered in
step 6, will now be displayed.
9) To quit the calibration mode, the key has to be
pressed again and the instrument is ready to perform
measurements within its range.
4.4 How to perform measurements
The instrument always stored the last measured value until
a new measurement is made. In order for the transducer
working in the right way there may not be any gaps
between the contact area of the sensor and the surface of
the material being measured. This is accomplished with
the coupling fluid, commonly called “couplant”. This fluid