Extech CG304 Operating Manual

USER MANUAL

Coating Thickness Tester

With Bluetooth®

Model CG304

Additional User Manual Translations available at www.extech.com

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Introduction

Thank you for selecting the Extech CG304 Coating Thickness Tester. The CG304 is a portable
meter designed for non-invasive coating thickness measurements with automatic recognition of
the material under test.

The meter uses two measurement methods: magnetic induction (for ferrous metal substrates)
and eddy current (for non-ferrous metal substrates).

The Bluetooth® feature wirelessly transmits measurement data to a Bluetooth receiving device
for further analysis and for generating report documentation.

Proper use and care of this meter will provide many years of reliable service.

Features

• Measured Coatings: Non-magnetic coatings (e.g. paint, zinc) on steel; Insulated Coatings (e.g.

paint, anodized coatings) on non-ferrous metals

• Intuitive menu-based programming

• Memory storage of up to 2500 readings in 50 groups (50 readings per group)

• Delete single readings or reading groups easily

• Bluetooth® interface feature wirelessly transmits measurement data to your PC for further

analysis and to generate a documented report.

• Auto Power OFF with disable feature

• User Zero Calibration ability

Applications

• Corrosion protection

• Paint Shops and Electroplaters

• Chemical, Automobile, Shipbuilding, and Aircraft industries

• Laboratory, Workshop, and Field use

Probe Description

The CG304 probe is spring mounted in the sensor sleeve. This ensures safe and stable positioning
of the probe and ensures constant contact pressure. A V-groove in the sleeve of the probe
facilitates reliable readings on small cylindrical parts. The hemispherical tip of the probe is made
of hard and durable material. Hold the probe by the spring mounted sleeve when applying
pressure on the measured object.

Measuring metallic coatings

This meter can measure non-magnetic metal coatings (Zinc) on a magnetic (ferrous) substance
base, and non-metal coatings on a metal base (ferrous or non-ferrous).

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Description

Meter Description

1. LCD display

2. Power button

3. Sensing Probe

4. Navigation buttons

Note: Battery compartment on rear of meter

Display Description

1. Data record memory group number

2. Record Number in current memory group

3. Bluetooth icon

4. Automatic (Auto) metal detect mode

5. Battery status icon

6. Measurement units: µm = Micrometers;

mils = millimeters * 2.54/100

7. Metal type (FE=ferrous, NFE=non-ferrous)

8. Measurement reading

9. DEL (Delete): Press the RIGHT arrow button to delete the displayed reading

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Operation

Meter Power

Install two ‘AAA’ 1.5 V batteries into the rear battery compartment. Press the power button
to switch the meter ON. The display will switch ON. If the display does not switch ON, install or
replace the batteries. When powering up, please keep the meter at least 10cm (4”) from metal
objects. Replace the batteries when the battery status icon appears low, the meter will give
inaccurate readings if the battery voltage falls very low.

Measurements

Before each measurement session, please perform a Zero Calibration as described later in this
User Guide. Practice with the film and zero (round) reference metal substrates to learn how the
meter operates before moving to a professional application. The heavier metal substrate is the
ferrous (magnetic) zero substrate and the lighter metal substrate is the non-ferrous (non­magnetic) zero substrate. The meter automatically senses ferrous and non-ferrous substrates.

1. Place a reference film (250µm, for example) on the round, ferrous substrate.

2. Power the meter by pressing the power button if necessary.

3. Place the spring-loaded meter sensor against the reference film.

4. The meter will emit an audible tone indicating that the measurement has been taken.

5. The LCD will show the reading (250µm) at the center of the display area.

6. A typical display will also show the following:

• Group(x): Upper left; Reading Memory Group

number (0~50). Use the up/down arrow buttons to
scroll groups

• (x): Upper right; Number of readings (0~50) stored in

current group

• Battery status icon at upper right

• DEL: Press the RIGHT arrow button to delete the displayed reading

• Fe or NFE: Ferrous or Non Ferrous substrate on the lower left of the LCD

• Bluetooth icon: When Bluetooth operation is active

• Automatic Metal detect mode (dual arrows)

Experiment with the remaining reference films and the substrates before using the meter
professionally.

Automatic Power OFF

In order to conserve battery life, the meter will automatically turn off after approximately 3
minutes. To defeat this feature, use the programming menu detailed in the next section (menu
parameter AUTO POWER OFF under SET).