ULTRASONIC THICKNESS GAUGE

MODEL ETM-2
OPERATING MANUAL

Manufactured by:

ELECTRONIC & ENGINEERING CO. (I) P. LTD.

DIV. PARIKH INDUSTRIES
Dadra 396 230.
Marketed by:

ELECTRONIC & ENGINEERING CO. (I) P. LTD.

8, Jyoti Wire Industrial Estate, 2nd Floor, Off Veera Desai Road,
Andheri (W), Mumbai-400053. INDIA.
Tel.: 91-22-61503800/26735050, Fax: 91-22-6691 9792
E-mail: ndtsales@eecindia.com Website: www.eecindia.com

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

INDEX

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DESCRIPTION
GENERAL INFORMATION
SPECIFICATION
BASIC OPERATION
CALIBRATION
MEASUREMENT IN INCHES
DISPLAY
BATTERY REPLACEMENT
PRECAUTION
HINTS ON GOOD MEASUREMENT
VELOCITY OF COMMON MATERIALS

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

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1. GENERAL INFORMATION
ETM-2 is a microcontroller based digital Thickness measuring gauge based on
Ultrasonic Principle and transit time measurement. It is designed to make accurate and
reliable measurements from one side of the component.
The small size, hand held gauge uses highly advanced sophisticated manufacturing
technology to offer simplicity and ease of operation. No prior training is essential to
make good measurements.
The gauge is designed to be used in rugged site condition with the only component
subject to wear and tear being the probe. However basic precautions are necessary,
while handling to maintain good service life of the gauge. It will be a good practice to
avoid the gauge being subjected to dirt, rough handling and physical damage.
The measuring range of the gauge is 1.0mm to 199.9mm for ETM-2 with a resolution of
0.1mm.
Ultrasonic waves are generated in the probes and are transmitted through to the test spot
by locating the probe correctly. The Ultrasonic waves travel under the probe, through
the cross section and are reflected back by the material boundary. The time taken for the
to and fro travel is recorded and converted to display the thickness. It is essential that
the test spot surface and the other end material boundary are parallel to each other.
The gauge includes (optional items also) the following:1. Ultrasonic Thickness gauge Model ETM-2
2. Protective cover PC2 & carrying case model CC2
3. Probes:
P.81 general purpose application
P.86 smaller diameter tubes, thin plates and in limited access application
P.61 -general purpose application
P.66 -smaller diameter tubes, thin plates and in limited access application
P.45 -general purpose application but at elevated surface, up to 450c
P.21 -high penetration type for attenuating materials like alloy steel and nonferrous
4. Instruction Manual code IM2
5. Calibration Blocks : SB-10, SB20
6. Couplants
: EZG, EZGHF, EZGVHT, EZGT
Application examples are plate, tubes, vessel wall, castings, forgings, corroded tanks
and pipelines, boiler tubes, metal structure, machined components in ferrous and non
ferrous metals. Non- metals like glass, plastic sheets and tubes, certain composites,
plastic tanks etc.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

2. SPECIFICATION
1. Thickness measuring range

: 1.0mm to 199.9mm/0.039inch to7.87inch in

steel @ 25 Degree
centigrade (Range is dependent on
material, transducer type and surface
Condition).

2. Display resolution

: 0.1mm. / 0.0039inch

3. Measurement rate

: One reading per Sec.

4. Material velocity range

: 1.40M/msec to 7.99M/msec&
0.055inches/sec to 0.314inches/sec

5. Material velocity calibration

: Either directs velocity entry or using

Known thickness block.

6. Display

: 3 and Digit, 0.5 Inch in height.

7. Thickness display units

: mm / inch.

8. Velocity display units

: meters/msec. &inches/sec

9. Measurement method

: Pulse Echo.

10. Gauge calibration check

: Using known velocity or 5mm block.

11. Auto OFF time

: 120 sec after last reading.

12. Key pad

: Sealed tactile.

13. Operating temperature rang e : 0 to 50 Degree centigrade.

14. Power

: 2 nos. AA cells.

15. Battery discharge time

: 30 hrs for Alkaline battery.

16. Size

: 120mm X 60mm X 25mm

17. Weight

: 190gms.

18. Accessories

: Protecting cover, carrying case,

operating manual & probe P.81
Calibration certificate, calibration
procedure)

19. Optional Accessories

: Probes: P.81, P.86, P.61, P.66, P.21, P.45.

Calibration blocks & couplants.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

3. BASIC OPERATIONS

2
3

1. POWER ON-OFF KEY

2. SLEW KEY: INCREMENTAL
3. SLEW KEY: DECREMENTAL
4. ONE STEP CALIBRATION KEY
5. HIGH CONTRAST LCD DISPLAY
6. TRANSMITTER SOCKET TO PROBE
7. RECEIVER SOCKET TO PROBE

NOTE: CONNECT Rx WITH RED COLOUR PROBE SLEEVE CONNECTOR

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

3.1 CONTROLS

: 1.

ON/OFF
instrument.

Key to turn ON or OFF the

2. SLEW KEYS:
calibration values.

3.

CAL

UP & DOWN, to change

Key to operate the instrument in calibration

mode.
3.2

PROBES

: A range of probes are available to be used for the most

appropriate application. Refer instrument catalogue or
contact us for more information. All probes are dual
crystal, transmitter- receiver type.

3.3

COUPLANT

: It is necessary to remove air between the test spot surfaces

and the probe surface to make a measurement. Liquids like
oil or grease are applied to test spot prior to placing the
probe for measurement. A range of couplants, most suited
for an application are also available on request. The
applied couplant should form a thin layer under the probe
tip.

3.4 INITIAL SETUP : Procedure while operating the gauge for mild steel
material, similar to the test block included on the gauge.
mild steel, velocity 5890 m/sec has been preprogrammed
in the microprocessor.
Step1. Connect the probe. Plug the probe into the
connector at the top end of the thickness gauge.
Red colour probe connector to red colour gauge
socket.
Note:- When unplugging a transducer pull ONLY on
Lemo plug, NOT on the cable.
Step2. Wipe all couplant from the tip of the transducer.
If the probe surface is uneven, slightly grind the
probe surface on sand paper in 8 directions.
Follow the procedure given for

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

3.5 DISPLAY INDICATIONS FOR OPERATION

Press

ON
OFF

key to start MANUAL-operating mode.

DISPLAY STATUS

Display

Software version
may be different.

Software Version

Probe No

Use

key to change probe.

Last selected probe

will be displayed
first.

CAL

Key
press

Metric units
mode.

Velocity

Probe not
sensed

Message displays if
probe not sensed

Probe not on job

Message blinks till

probe not put on 5mm
block. Gauge will shut
off after 25 blinks.

Probe on 5mm
calibration block

Small triangle blinks in

upper left corner of lcd,
indicates manual
calibration in process.

Calibration over.

Small triangle in upper

left corner indicates
probe is on the job &
job thickness is 5mm.

Probe on job

Display thickness.

Gauge is calibrated and ready to measure unknown thickness

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

3.6 OPERATION

: Step1. Apply couplant to the test block or material at the

spot to be measured. In general, the smoother the
material surface, the thinner the couplant may be.
Rough surfaces require more viscous couplant
such as gel or grease.
Step2. Place the tip of the transducer on the surface of
the material to be measured. Keep the transducer
as flat as possible on the material surface.
Step3. Read the thickness on the gauge display.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

4. CALIBRATION

4.1 CALIBRATION WITH KNOWN VELOCITY:

Procedure while operating the gauge for material other than Mild Steel, unknown
thickness and known velocity.

Step1. Connect the probe to the gauge.

Step2. Ensure probe tip is clean and press the

ON/OFF

Key.

Step3. Select probe type using SLEW KEY

The probe nos.
displayed by gauge must be same as on the probe label.
Step4. Press

CAL

Step5. Press

Key. Follow the procedure as per 3.5

twice.

Step6. Use SLEW Keys

and
to correspond the displayed
reading with that of known value.
CAL
Step7. Press
Key. After a second the gauge will be ready
to measure thickness of material with known velocity.
4.1.1 VELOCITY READ OUT:
Step1. Calibrate the gauge as in 4.1
Step2. Press
the key.
The display will read velocity in M/msec, for e.g. 5.89 means
5.89M/ms or 5890M/sec.
4.1.2 CALIBRATION ERROR:
In case error prompt is displayed when the gauge is turned on,
(possibly due to weak battery) the gauge will reload its internal set up. In such a
case CAL prompt will be flashed thrice. Normal calibration can follow if
required.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

5. MEASUREMENT IN INCHES [ ~ ]
Procedure while operating the gauge for mild steel. Material, similar to the test block
included on the guage. Mild steel, Velocity 0.232 inches has been preprogrammed in
the microprocessor.
For mm to inches OR from inches to mm press ON/OFF &
key
simultaneously. First, release

ON/OFF

key & then release

key.

INITIAL SETUP: Procedure while operating the gauge for mild steel
Material, similar to the test block included on the gauge.
Mild steel, velocity 0.232 inches has been preprogrammed
in the microprocessor.
Step1. Connect the probe. Plug the probe into the
connector at the top end of the thickness gauge.
Red colour probe connector to Red colour gauge socket
Note: - When unplugging a transducer pull ONLY on
Lemo plug, NOT on the cable.
Step2. Wipe all couplant from the tip of the transducer.
Follow the procedure as per 3.5.
Gauge is calibrated and ready to measure unknown thickness.

CALIBRATION WITH KNOWN VELOCITY WILL BE SAME AS

MEASUREMENT IN MM.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

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6. DISPLAY
Various displays are as follows: -

START.

: Software version.

: Probe connection flashes continuously when

improper.

: Error in calibration. Old calibration retained.

: Reading exceeding 199.9m.

: Indicates gauge is in calibration mode. Will hold till

sample measurement is made.

: Ready to measure.

: Measured reading in mm (for e. g.)

: Velocity in M/ms (for e. g.)

: Valid measured reading.

: Replace battery.

: Probe number.

: Measurement in inch

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

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7. BATTERY REPLACEMENT
For replacing the batteries, open the gauge back cover by sliding the cover towards your
side & replace the old batteries with the new ones.

8. PRECAUTION
Avoid applying pressure on the display, because of which it can get damaged within
no time. Avoid dropping the gauge and use it carefully.
Do not open the set. It contains electronic components that can be damaged. Refer
servicing to trained personnel only.
The probe does not need special caution. Clean them after each use.
Ensure probe tip is not pitted or worn out. It should always be flat.
Do not pull on the cables in order to avoid bad electric contacts and damage to the
connectors. Light pull on the connector body is sufficient.

9. HINTS ON GOOD MEASUREMENT

9.1 Select a right type of probe, most suitable for the assignment.
9.2 Calibrate the gauge first on a 5mm test piece.
9.3 Clean the test location and ensure it is free of scales, dirt or loose paint/coatings.
The surface should be reasonably smooth. If it is pitted, smoothen with sand
paper.
9.4 Apply small amount of couplant on the test spot.
9.5 With even pressure (not hard) place the probe firmly on the test spot and hold until
the display reads, allow about 1 sec. to make a good measurement.
9.6 Do not rub the probe on the test surface, as it will increase wear & tear of the
probe.
9.7 Use a high temperature probe and couplant for measuring components that are at
temperatures above 60 C. Apply small amount of couplant on the probe tip and
then place probe on the test surface. Remove probe immediately when there is a
valid reading. Probe should not be heated or else it can be permanently damage.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

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10. VELOCITY OF COMMON MATERIAL

MATERIAL

VELOCITY (M / SEC)

ALUMINIUM

6320

IRON (STEEL)

5900

S. STEEL (302)

5600

S. STEEL (410)

7390

CAST IRON

3500-5600

COPPER

4700

NICKEL

5630

LEAD (PURE)

2160

TITANIUM

6100

TUNGSTEN

5180

GLASS

5770

LUCITE

2670

TEFLON

1350

NYLON

1800-2200

QUARTZ

5730

PERSPEX

2730

GLYCERIN

1920

WATER

1483

OIL

1410

RUBBER (VULCANIZED)

2300

Above velocities are approximate, for reference only. Due to material composition, they
may be different in the actual test component.

INSTRUCTION MANUAL FOR ETM-2 VER. 3.0

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