Calibration Adjustment; Calibration Method - Elcometer 456 3 Operating Instructions Manual

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5 CALIBRATION ADJUSTMENT

Calibration adjustment is the process of setting the
gauge to known values of thickness to ensure
accuracy on different substrate types, shapes and
surface finishes.
Note: When using an FNF probe it must be
calibrated in both the ferrous mode and in the non-
ferrous mode to ensure accuracy of reading.

5.1 CALIBRATION METHOD

The calibration of the gauge can be adjusted
(MENU/CAL METHOD) using several different
methods described in National and International
Standards.
The calibration adjustment method chosen is
dependant on the condition of the substrate to be
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measured and is indicated on the screen by a
symbol (Figure 21):
Figure 21. CAL METHOD screen
SMOOTH: Smooth surface calibration where the
gauge is set to zero on the uncoated surface and a
known thickness above the expected thickness of
the coating.
2POINT: Calibration on a thin value and a thick
value either side of the expected thickness. This
enhances the accuracy of the gauge over the
thickness range defined by the two values.
ROUGH: A calibration method similar to 2-Point.
This enhances the accuracy of the gauge over the
thickness range defined by the two values.
SPECIAL SUB: This method uses the 2-Point
calibration for unusual substrate materials such as
cast iron, certain types of stainless steel, high
carbon steel, special aluminium alloys, etc.