Elcometer CG20 User manual

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Model CG10 & CG20
Corrosion Gauge
Operating Instructions

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This product meets the Electromagnetic Compatibility Directive.
The product is Class A, Group 1 ISM equipment according to CISPR 11.
Group 1 ISM product: A product in which there is intentionally generated and/or used conductively coupled radio-frequency
energy which is necessary for the internal functioning of the equipment itself.
Class A product are suitable for use in all establishments other than domestic and those directly connected to a low voltage
power supply network which supplies buildings used for domestic purposes.
Note : In the close presence of some radio transmitters, erroneous readings may be given. If this occurs tests should be
repeated at another location.
These operating instructions are available for download on our website www.elcometerndt.com.
The following trademarks are registered trademarks of Elcometer Limited, Edge Lane, Manchester, M43 6BU. United
Kingdom:
Material Safety Data Sheets for the ultrasonic couplant supplied with the CG10 & CG20 and available as an accessory, are
available to download via our website:
Elcometer NDT Ultrasonic Couplant Material Safety Data Sheet :
www.elcometerndt.com/images/MSDS/elcometer_ultrasonic_couplant.pdf
Elcometer NDT Ultrasonic Couplant Material Safety Data Sheet :
www.elcometerndt.com/images/MSDS/elcometer_ultrasonic_couplant_hi_temp.pdf
All other trademarks acknowledged. © Elcometer Limited 2011-2012. All rights reserved. No part of this document may be
reproduced, transmitted, transcribed, stored (in a retrieval system or otherwise) or translated into any language, in any form
or by any means (electronic, mechanical, magnetic, optical, manual or otherwise) without the prior written permission of
Elcometer Limited. TMA-0553 Issue 01
Text with cover: 23730

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Contents
1 About your Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 The Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 The Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Setting up the Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Taking Readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9 Technical Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11 Spares & Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
12 Condition and Preparation of Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
13 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
14 Sound Velocities of Common Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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Thank you for purchasing this Elcometer product. Welcome to Elcometer NDT.
The Model CG10 and CG20 Corrosion Gauges are world beating products. With the purchase of this gauge
you now have access to the worldwide service and support network of Elcometer NDT. For more
information visit our website at www.elcometerndt.com.
1 ABOUT YOUR GAUGE
The Model CG10 and CG20 are corrosion gauges that measure with extreme versatility. They have the
ability to measure coatings and material thickness simultaneously while maintaining the ability to locate pits,
flaws and defects in the material. Based on the same operating principles as SONAR, the Model CG10 and
CG20 is capable of measuring the thickness of various materials with accuracy as high as 0.01 millimetres
(0.001 inches). The principal advantage of ultrasonic measurement over traditional methods is that
ultrasonic measurements can be performed with access to only one side of the material being measured.
1.1 STANDARDS
Your gauge can be used in accordance with the following Standards and test methods; ASTM E 797,
EN 14127 and EN 15317.
1.2 WHAT THIS BOX CONTAINS
Model CG10 and CG20, Bottle of couplant, Battery (2 x), Carrying case, Test certificate, Operating instruc-
tions, CD with sound velocity programming software, RS232 cable and USB Serial converter.
Note: The box does not include a transducer; these must be ordered separately. To order a transducer,
contact Elcometer NDT or your local Elcometer NDT supplier.

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1.3 PACKAGING
The gauge is packed inside its carry case within a cardboard box. Please ensure that the packaging is
disposed of in an environmentally sensitive manner. Consult your Local Environmental Authority for further
guidance.
To maximise the benefits of your new Elcometer NDT gauge, please take some time to read these
Operating Instructions. Do not hesitate to contact Elcometer NDT or your Elcometer NDT supplier if you
have any questions.

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2 THE KEYPAD
Key Functions Model
Press to switch the gauge on or off.
When switching off, the gauge retains all of its settings.
If the gauge is idle for 5 minutes, it will switch itself off.
CG10
CG20
Press to change units (metric/imperial) CG10
CG20
Switches the display backlight between three settings; on, off and auto.
• ON - backlight is on
• OFF - backlight is off
• AUTO - backlight automatically illuminates while the gauge is making a meas-
urement and switches off after several seconds (to conserve battery life).
CG10
CG20
Press to zero the gauge CG10
CG20
Press to select material type. CG20
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3 GETTING STARTED
3.1 FITTING BATTERIES
Your gauge may be used with dry cell batteries or rechargeable
batteries. 2 x LR6 (AA) alkaline batteries are supplied with this gauge.
When the battery voltage is low the entire display will start to flash. When
this occurs the batteries should be replaced.
To fit or replace batteries:
1. Unscrew battery compartment cover.
2. Referring to battery polarity instructions on rear of gauge, insert bat-
teries into gauge ensuring correct polarity.
3. Replace battery compartment cover.
Note: Remove the batteries from the gauge if it is to remain unused for
a long period of time. This will prevent damage to the gauge in the event
of malfunction of the batteries.
Battery
compartment
cover
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Model CG20

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3.2 FITTING THE TRANSDUCER
The transducer transmits and receives ultrasonic sound
waves that the gauge uses to calculate the thickness of the
material being measured.
The transducer connects to the gauge via the attached cable,
and two coaxial connectors. When using transducers
manufactured by Elcometer NDT, the orientation of the dual
coaxial connectors is not critical; either plug may be fitted to
either socket.
The transducer must be used correctly in order for the gauge to produce accurate, reliable measurements.

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4 THE DISPLAY
Note: The display will hold the last value measured, until a new measurement is made.
Note: When the battery voltage is low, the entire display will begin to flash. When this occurs, the batteries
should be replaced.
Stability indicator
• One vertical bar - no
readings are being taken
• Less than 5 bars - read-
ing is unstable and may
be inaccurate
• More than 5 bars - read-
ing is stable
Units (IN, MM, IN/µs, M/s)
Measurement value/Text
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5 SETTING UP THE GAUGE
5.1 TRANSDUCER - ZEROING
Setting the zero point for the transducer is important for the same reason that setting the zero on a
mechanical micrometer is important. If the zero point of the transducer is not set correctly, all of the
measurements the gauge makes will be in error by some fixed number.
Though the gauge will remember the last zero point, it is generally a good idea to set the zero point
whenever the gauge is switched on, and always when a different transducer is used.
The zero probe routine must be done prior to calibration.
1. Switch on the gauge and connect the transducer.
2. Remove all couplant from the face of the transducer and check that the
wearface of the transducer is clean and free of any debris.
3. Apply a drop of couplant on the transducer and place the transducer in
steady contact with the probe zero disk (the battery cover located on
the top of the unit), and obtain a steady reading.
The display should show a thickness value, and nearly all the bars of
the stability indicator should be illuminated.
Note: The value that is displayed will change depending on the current
velocity setting in your gauge. Disregard the value displayed; it is not
important. What is important is accurately performing these steps to
ensure reliability of the zero calculation.
4. While the transducer is firmly coupled to the disc, press .
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The display will show ‘Prb0’ while it is calculating its zero point.
5. Remove the transducer from the probe zero disk.
Your gauge is now zeroed.
5.2 CALIBRATING
In order for the gauge to make accurate measurements, it must be calibrated to the sound-velocity of the
material being measured.
Different types of material have different sound-velocities. For example, the velocity of sound through steel
is 5918 m/s (about 0.233 in/µs) and the velocity of sound through aluminium is 6350 m/s (about
0.248 in/µs). If the gauge is not set to the correct sound-velocity, all of the measurements the gauge makes
will be erroneous by some fixed percentage.
The CG10 gauge can store one material sound velocity that can be adjusted by connection to a computer
see ”Editing the User-defined Sound-velocity Values” on page 10.
To calibrate your CG20 gauge for the material you are measuring, you select the material from a list of
materials stored in the gauge. For each material stored in the list there is a corresponding sound-velocity
value. There are eight factory-set materials which you cannot change, plus two user-definable sound-
velocity values :

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5.2.1 Selecting a material and sound-velocity (CG20 only)
Repeatedly press until the material/sound-velocity you require is displayed.
Display Material Sound-velocity
m/s in/µs
StL Steel 4340 5918 0.233
StSt Stainless Steel 303 5664 0.223
Alu Aluminium 2024 6350 0.251
IrOn Cast Iron 4572 0.179
PLE Plexiglass 2692 0.106
PVC PVC 2388 0.094
PLSt Polystyrene 2337 0.092
PLur Polyurethane 1778 0.070
uSr1 User-defined sound-velocity 1
uSr2 User-defined sound-velocity 2
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5.2.2 Editing the User-defined Sound-velocity Values
To calibrate your gauge for the material you are measuring, use ElcoMaster™2.0 software to change the
stored material velocities.
Connect the gauge to your PC and the software, then follow the on screen instructions to change the
calibration values.
6 TAKING READINGS
Disclaimer: Inherent in ultrasonic thickness measurement is the possibility that the instrument will use the
second rather than the first echo from the back surface of the material being measured. This may result in
a thickness reading that is TWICE what it should be.
Responsibility for proper use of the instrument and recognition of this phenomenon rests solely with the user
of the instrument.
Other errors may occur from measuring coated materials where the coating is insufficiently bonded to the
material surface. Irregular and inaccurate readings may result. Again, the user is responsible for proper use
and interpretation of the measurements acquired.
6.1 BEFORE YOU START
• Prepare the surface - see ”Condition and Preparation of Surfaces” on page 18.
• Set the zero point of the transducer - see ”Setting up the Gauge” on page 7.
• Select units; press to select metric (mm) or imperial (inches).
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6.2 PROCEDURE
1. Apply couplant
For the gauge to work correctly there must be no air gap between the transducer and the surface of
the material to be measured. This is achieved using a couplant.
Before the transducer is placed on the surface, put a small amount of couplant on the surface of the
material. Typically a single drop is sufficient.
2. Place transducer onto the surface of the material to be measured
Press the transducer wearface into the couplant. Moderate pressure on the top of the transducer using
the thumb or index finger is sufficient; it is only necessary to keep the transducer stationary and the
wearface seated flat against the surface of the material.
3. Read display
If six or seven bars of the stability indicator are showing, the display will be reading the correct thick-
ness of the material directly beneath the transducer.
If the stability indicator has fewer than five bars showing, or the numbers on the display seem erratic,
check to make sure that there is an adequate film of couplant beneath the transducer, and that the
transducer is seated flat against the material.
The gauge will perform a number of measurements every second when the transducer is in contact
with the surface of the material. The display is updated as each reading is taken.
4. Remove transducer from surface
The display will show the last measurement made.
Note: Occasionally, a small film of couplant that is left on the transducer surface will be measured by the
gauge as it is removed. Using less couplant can reduce this effect.

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7 STORAGE
Your gauge has a Liquid Crystal Display. If the display is heated above 50°C (120°F) it may be
damaged. This can happen if the gauge is left in a car parked in strong sunlight.
Always store the gauge in its case when it is not being used.
If the gauge is to remain unused for long periods of time, remove the batteries and store them
separately. This will prevent damage to the gauge in the event of malfunction of the batteries.
8 MAINTENANCE
You own one of the finest corrosion gauges in the world. If looked after, it will last a lifetime.
8.1 FAULTS
Your gauge is designed to give many years reliable service under normal operating and storage conditions.
The gauge does not contain any user-serviceable components. In the unlikely event of a fault, the gauge
should be returned to your local Elcometer NDT supplier or directly to Elcometer NDT. The warranty will be
invalidated if the instrument has been opened.
8.2 TRANSDUCER
The transducer will wear with repeated use. Transducer life depends on the number of measurements taken
and the manner in which readings are taken. To extend transducer life, always set the transducer down so
that it is perpendicular to the panel surface. Dragging the transducer along the surface will reduce the life
ofthe transducer. Replacementtransducers areavailable from your local Elcometer NDT supplier or directly
from Elcometer NDT.

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9 TECHNICAL SPECIFICATION
Measurement Rate (Manual) 4 readings per second
Measuring Rangea
a. Measuring Range depends on material, surface conditions and the transducer selected.
0.63 mm to 500 mm (0.025” to 19.999”)
Measurement Resolution 0.01 mm (0.001")
Velocity Calibration Range 1250 m/s to 10000 m/s (0.0492 in/µs to 0.3937 in/µs)
Velocity Selection Options CG10 - One user programmable velocity
CG20 - Two user-programmable velocities 8 pre-calibrated velocities (aluminium,
cast iron, plexiglass, polystyrene, polyurethane, PVC, stainless steel and steel)
Weight (including batteries) 284 g (10 oz)
Dimensions (W x H x D) 63.5 mm x 114.3 mm x 31.5 mm (2.5” x 4.5” x 1.24”)
Gauge Operating Temperature -30°C to 50°C (-20°F to 120°F)
Case Aluminium case with gasket sealed end caps and waterproof membrane keypad
PC Connection RS232 serial port. Windows PC interface software
Display 12.7 mm (0.5 “) high digits with LED backlight (on/off/auto).
Power Source Two 1.5 V AA alkaline or 1.2V rechargeable cells. Typically operates for 200
hours on alkaline and 120 hours on rechargeable cells (charger not included.)
Note: Alkaline batteries must be disposed of carefully to avoid environmental
contamination. Please consult your local environmental authority for information
on disposal in your region. Do not dispose of any batteries in fire.

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10 WARRANTY
Elcometer NDT warrants your gauge against defects in materials and workmanship for a period of two years
from receipt by the end user.
Additionally, Elcometer NDT warrants transducers and accessories against such defects for a period of 90
days from receipt by the end user. If Elcometer NDT receives notice of such defects during the warranty
period, Elcometer NDT will either, at its option, repair or replace products that prove to be defective. The
warranty will be invalidated if the instrument has been opened.
10.1 EXCLUSIONS
The above warranty shall not apply to defects resulting from: improper or inadequate maintenance by the
customer; unauthorised modification or misuse; or operation outside the environmental specifications for
the product.
Elcometer NDT makes no other warranty, either express or implied, with respect to this product.
Elcometer NDT specifically disclaims any implied warranties of merchantability or fitness for a particular
purpose. Some states or provinces do not allow limitations on the duration of an implied warranty, so the
above limitation or exclusion may not apply to you. However, any implied warranty of merchantability or
fitness is limited to the two-year duration of this written warranty.
This warranty gives you specific legal rights, and you may also have other rights, which may vary from
country to country, state to state or province to province.

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10.2 OBTAINING SERVICE DURING WARRANTY PERIOD
If your hardware should fail during the warranty period, contact Elcometer NDT and arrange for servicing of
the product. Retain proof of purchase in order to obtain warranty service.
For products that require servicing, Elcometer NDT may use one of the following methods:
• Repair the product
• Replace the product with a re-manufactured unit
• Replace the product with a product of equal or greater performance
• Refund the purchase price.
10.3 AFTER THE WARRANTY PERIOD
If your hardware should fail after the warranty period, contact Elcometer NDT for details of the services
available, and to arrange for non-warranty service.

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11 SPARES & ACCESSORIES
11.1 TRANSDUCERS
Elcometer NDT gauges are not supplied with a transducer as standard - this must be ordered separately.
The transducers listed below are the most commonly used however, Elcometer NDT offer a wide range of
other transducers to suit various applications.
Further information on the transducers available and their applications can be found on the Elcometer NDT
Knowledge Centre on www.elcometerndt.com.
Description Sales Part No.
2.25 MHz 1/4” Potted Side Transducer TX2M25CP-2
5 MHz 1/4” Potted Side Transducer TX5M00CP-4
5 MHz 1/4” Potted Side High Damped Transducer TX5M00CP-10
7 MHz 1/4” Potted Side High Damped Transducer TX7M50CP-6
10 MHz 1/4” Potted Side Transducer TX10M0CP-4
11.2 CALIBRATION BLOCKS
Elcometer NDT offer a comprehensive range of calibration blocks to suit a wide range of applications and
standards.
Selecting the correct calibration block for the application is essential to ensure accurate evaluation. The
form, shape and material of the calibration block should be appropriate for the material being inspected.
Any artificially induced flaw should closely resemble that of the actual flaw being tested for.
The calibration blocks listed below are a selection of those available - details of the full range can be found
on www.elcometerndt.com.

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Description Sales Part No.
Calibration Block: 8 Step; 1 - 8mm TW-24005-*
Calibration Block: 10 Step; 2 - 20mm TW-24006-*
Calibration Block: 10 Step; 2.5 - 25mm TW-24007-*
Replace * with S1018 = 1018 Steel Block; A = Aluminium Block; SS = Stainless Steel Block;
T = Titanium Block.
11.3 ULTRASONIC COUPLANT
Each gauge is supplied with a 120ml (4oz) bottle of standard ultrasonic couplant. Replacement bottles and
couplant for high temperature applications are available from your local Elcometer NDT supplier or directly
from Elcometer NDT.
Description Sales Part No.
Ultrasonic Couplant, 120 ml (4 oz) TC-24034-1
Ultrasonic Couplant, 360 ml (12 oz) TC-24034-2
Ultrasonic Couplant, High Temperature 343°C (650°F), 120 ml (4 oz) TC-24034-4X
Ultrasonic Couplant, High Temperature 482°C (900°F), 120 ml (4 oz) TC-24034-5X
Note: A wide range of other transducers and accessories is available - see www.elcometerndt.com for
details.
11.4 MISCELLANEOUS
Description Sales Part No.
RS232 Cable USB to Serial Converter TL-24031