6. Calibration
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MiniTest 2500 - MiniTest 4500
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This calibration method should be used if readings are to be taken over an extended thickness
range and if a high accuracy is required.
6.2.2.4 Two-point Calibration without zero
The status line shows:
“12“
.
Calibration points: two precision standards) (no zero point).
Calibration is to be made on an uncoated calibration sample of the same geometry and material as
the later measuring object. Two calibration points are to be taken on two precision standards which
are to be put on the substrate. The first precision standard should be thinner than the thickness to
be expected, the other one should be thicker than the thickness to be expected. There is no zero
point to be taken directly on the uncoated sample. There is no zero point to be taken directly on the
uncoated sample.
This specific calibration method should be used when taking readings on rough surfaces. Taking
zero point on rough surfaces would imply strong deviations due to the une
ven surface. That’s why
zero point is omitted in this calibration method as this would lead to erratic calibration and thus
affect accuracy.
6.2.2.5 Calibration through a coating (CTC)
The status line shows:
“CTC“.
Calibration using a calibration foil. Recommended if the test sample is coated and no uncoated
sample is available for comparison. This method is suitable for the following probes. F05, F1.6,
F1.6/90, F3 and FN1.6 (only F-part), F1.6/90, F10, F20 and F50.
6.4.3.1 Calibration of FN-type sensors
Calibration can be performed in direct mode or in an active batch for
the F-part as well as for the N-part of the system.
If “Auto FN“ is activated, pressing of the “Zero” or the “Cal” key will
display the message “Substrate”. Select Fe or NFe using the keys „
“or „
“ and confirm with the “OK” key. .
If no selection is made at all, the gauge will automatically display
FERROUS after about 5 secs. And select the magnetic induction
method
.