Calibration Types; Calibration Considerations; Preparing For Calibration - Extech Instruments CG304 User Manual

Calibration
Calibration Types
The meter is factory calibrated before shipment to the customer; however the customer should
perform a zero calibration and a multi‐point calibration before any critical measurements are
taken. The calibration options are listed below. Read the description for each and select the
best match for a given application.
1. Zero Point Calibration: Perform before each measurement session.
2. One Point Calibration: Use for high accuracy with repeated tests on a constant coating
thickness.
3. Multi‐Point Calibration: Use for high accuracy within a known range of coating thickness.
4. Calibration for shot‐blasted surfaces.
Calibration Considerations
The calibration sample must correspond to the product sample in the following ways:
 Curvature radius
 Substrate material properties
 Substrate thickness
 Size of measurement area
 The point at which the calibration is made on the calibration sample must always be
identical with the point of measurement on the product itself, especially in the case of
corners and edges of small parts.
To achieve the highest measurement accuracy, perform several calibrations in succession (for
zero values and calibration film values).
Preparing for calibration
1. Clean the probe tip (grease, oil, metal scrap, and the slightest impurity will affect
measurement and distort readings).
2. Switch the meter ON (at a 4" [10cm] minimum distance from any metal).
3. Ready the supplied metal substrate samples and necessary films (supplied calibration
reference films).
4. The meter is now ready for calibration.
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