General EMHT40 User Manual

HARDNESS TESTER ASTM RATED—PEN STYLE

USER’S MANUAL

EMHT40

Please read this manual carefully and thoroughly before using this product.

99 Washington Street
Melrose, MA 02176

Phone [phone]
Toll Free 1-800-517-8431

Visit us at www.TestEquipmentDepot.com

TABLE OF CONTENTS

Introduction…………………………………………………………………………… 2-4
Key Features…………………………………………………………………………… 4-5
What’s in the Package………………………………………………………………. 5
Product Overview…………………………………………………………………….. 6-7
Setup Instructions……………………………………………………………………. 7-17

Navigating the Menus……………………………………………………….. 9-17

Operating Instructions……………………………………………………………… 18-20

Interfacing with a PC…………………………………………………………19-20
Specifications…………………………………………………………………………. 20
Operating & Maintenance Tips……………………………………………………. 21
APPENDIX—Non-conventional support rings…………………………………. 21-22

INTRODUCTION

The EMHT40 is a pen-style instrument that uses the Leeb testing method to measure the
hardness of any metal or surface for a wide variety of industrial purposes. The Leeb method is
notable for its accuracy, wide measuring range and operating simplicity.

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Typical applications for the EMHT40 include measuring the surface and coating hardness of
installed machines and components, die molding surfaces and bearings. Up to 1250 test
results can be stored in the EMHT40’s memory and ported to a PC for display as an Excel table
or graph.

Leeb hardness testing produces so-called Leeb hardness values for a target metal (the work
piece). To measure hardness, the user cocks a spring-loaded, pen-shaped plunger and
squeezes a trigger at one end of the instrument to fire the plunger (the impact device) against
the work piece at the other end. A permanent magnet close to the work piece senses the
impact and generates two voltages: one proportional to the plunger’s impact velocity and the
other proportional to the velocity with which the plunger rebounded from the work piece.

To determine the target’s Leeb hardness value—a parameter designated HL—an algorithm
within the EMHT40 divides the voltage representing the plunger’s rebound velocity by the
voltage representing its impact velocity and multiplies by 1000. The following formula is used
for the computation:

HL=1000 × (Vb /Va)

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where Vb is the voltage produced during the rebound of the impact device and Va is the
voltage produced during the impact of the impact device.

Leeb hardness values (HL) can be converted to values using other hardness units such as HV,
HRC, HRB, HB and HS. The EMHT40 can also display readings using several of these hardness
units. However, to maintain the accuracy of measurements all hardness values must describe
not just the testing method but the type of impact device as well.

For example, a hardness value of 510 on the Leeb scale determined by using the “D” type
tungsten-carbide impact device provided with the EMHT40 would be described as 510HLD.

KEY FEATURES

 Conforms to ASTM A 956
 Compact, easy to use and reliable
 Displays minimum, maximum and average values
 Wide measuring range, with display of hardness values in any of the following units:

Leeb HL, Rockwell HRB and HRC, Vickers HV, Brinell HB and Shore HS

 Impact device works at any angle, even upside down
 1250 reading internal memory and USB cable for interfacing to a PC

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 2-minute Auto Power Off
 2-year limited warranty

WHAT’S IN THE PACKAGE

The EMHT40 comes in a hard plastic carrying case inside a cardboard box. Inside the case
are:

 The pen-style EMHT40, incorporating a “D” type impact device.
 A standard hardness test block with a nominal hardness value of 777HLD.
 A cleaning brush and a conventional support ring in a Ziploc bag.
 An 110VAC adaptor with an output of 3.7VDC output available from a full-size USB jack.
 A cable with a full-size USB plug at one end and a mini-USB plug at the other. When

used to connect the EMHT40 to a PC, the cable trickle-charges the Lithium-ion battery

that powers the tester.

 A mini-disc containing 1) a program for displaying the contents of the EMHT40’s

memory on a PC, 2) drivers for Windows8 (64- and 32-bit), Windows7 (64- and 32-bit),

Windows Vista (64- and 32-bit) and WindowsXP, and 3) installation and operating

instructions for the program and drivers

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 This user’s manual

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PRODUCT OVERVIEW

The two following images show a typical EMHT40 display and the multiple functions provided
by the three-button keypad on the bottom of the unit. Familiarize yourself with the position of
all indications and the functions of the controls before moving on to the Setup Instructions
and Operating Instructions.

Display

 Hardness scale

 Measured value

 Average value

 Maximum value

 Minimum value

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 Memory location

 Remaining battery charge

 Number of measurements used for averages

 Material

 Direction of impact

Keypad

 On/Off/Save Setting

 Select/Move/Delete

 Select/Set/Change display style

SETUP INSTRUCTIONS

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The “D” type impact device built into the EMHT40 will provide optimal results for work pieces
with a surface roughness of 2μm.

A work piece should not be tested: 1) If its temperature is above 176oF (80oC); 2) It is within
a strong magnetic field; or 3) It is less than 0.12 in. (3mm) thick or has a surface-hardened
layer thinner than 0.03 in. (0.8mm).

Work pieces weighing more than 11 lb. (5kg) require no support.

Work pieces weighing between 4.4 and 11 lb. (2 and 5kg), as well as work pieces with
protruding parts or thin walls, should be anchored to a solid support to prevent them from
moving or flexing as a result of testing.

Work pieces weighing less than 4.4 lb. (2kg) should be tightly attached to a non-yielding
support such as a heavy base plate.

Work pieces with a cylindrical or spherical inside or outside surface radius of less than 1.18 in.
(30mm) require the use of the included support ring or a non-conventional support ring. The
Appendix illustrates and describes several key parameters of 12 support rings in common use.

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To power on the EMHT40, press the button. The typical display shown in the Product

Overview section will appear. To power off the EMHT40, press and hold the button for
at least 3 seconds.

NAVIGATING THE MENUS

Briefly pressing (but not holding) the button opens the EMHT40’s main menu screen of 10
items.

1. MEASUREMENT

2. AVG. TIMES

3. MAT. & SCALE

4. TOLERANCE

5. LOCATION

6. MEMORY

7. DATA OUTPUT

8. CALIBRATION

9. CONTRAST

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10. DEFAULT

Although it is not necessary to adjust the settings of all 10 items if you do not intend to store
your measurements or port them to a PC, it is good practice to do so to understand the
options available to you:

To select any item to view or change its setting, use the and buttons to move up or

down and highlight its line. Then briefly press (but do not hold) the button. In most cases,
selecting a main menu item displays either: 1) a default value that can be adjusted by using

the and buttons; or 2) a sub-menu of options that can be navigated using the same
buttons. To save any displayed setting (whether you have changed it or not), briefly press

the button. Doing so resumes display of the main menu screen.

Hint: Try not to take too much time to make your menu selections. The EMHT40 has an Auto
Power Off function that will automatically power off the unit during any 2-minute period
during which no buttons are pressed.

1. Selecting 1. MEASUREMENT displays the full measurement screen on the LCD.

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2. Selecting 2. AVG. TIMES displays the text AVERAGE TIMES over a number
representing the number of readings used to calculate an average value. Choices range
from 2 (the default) to 8. In most cases, choosing 3, 4 or 5 readings yields good

results. Pressing the button to save an “number of times” setting resumes display of
the main memory screen.

3. Selecting 3. MAT. & SCALE calls up two sub-menus in sequence. The first sub-menu
lists nine options for the work piece material: 1. ST. & CAST STEEL, 2. CWT. STEEL,

3. STAINLESS ST., 4. G. CAST IRON, 5. N. CAST IRON, 6. CAST ALUMINUM, 7.
BRASS, 8. BRONZES and 9. COPPER.

Pressing the button to save a material setting opens up a second sub-menu of six
hardness scale (unit) options: 1. HL, 2. HRC, 3. HRB, 4. HB, 5. HS and 6. HV.

Pressing the button to save a hardness unit resumes display of the main memory
screen.

4. Selecting 4. TOLERANCE displays an upper and a lower limit for measured hardness
values using the selected scale. Whenever a measurement is lower than the lower limit
or higher than the upper limit, L or H will appear on the measurement display.

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The first value available for viewing or changing is the upper hardness limit. The small
“up” arrow (see following screen shot) will first appear below the “thousands” digit on
the UPPER line. If the thousands digit is missing, that means the upper hardness limit
is less than 1000.

To change the thousands digit (including changing it from an invisible zero), press the

button as many times as necessary to reach the desired value. You can only

increase

the digit’s value by one per button press; to change the value from 6 to 5, for

example, you must 1) press the button three times to reach 9; 2) press it one more

time to reach 0, and then 3) press the button another five times to go from 0 to 5.

When you have set the thousands digit to the desired value, press the button to
save the setting. Doing so shifts the “up” arrow to right to the “hundreds” digit of the

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upper hardness limit. As with the thousands digit, you must press the button as
many times as necessary to reach the desired value of the hundreds digit. Then press

the button to save the hundreds digit setting and shift the arrow to the “tens” digit
of the upper hardness limit.
Repeat the above procedure for the tens and units digits of the upper hardness limit.

Note that when you press the button to save the units digit of the upper hardness
limit, the up arrow moves down, below the thousands digit of the LOWER line.
Repeat the procedure to set all four digits of the lower hardness limit. Note that when

you press the button to save the units digit of the lower hardness limit, the up
arrow moves up to its initial position, below the thousands digit of the UPPER line. At

that point, if you are satisfied with the settings of both hardness limits, press the
button to resume display of the main memory screen.

5. Selecting 5. LOCATION calls up a display similar to the TOLERANCE screen, but with

a 4-digit value below the text SET LOCATION. By alternating presses of the button

(to view or change the value of each digit) with presses of the button (to save
settings and select the next digit in turn), you can designate the number of the memory
location to store your next saved measurement. When you are satisfied with the

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memory location setting, press the button to resume display of the main memory
screen.

6. Selecting 6. MEMORY calls up a screen with the text OUTPUT over three options: 1.

SEQ. STORE; 2. BATCH STORE and 3. CLEAR MEMORY. Use the or button

to navigate to the desired option and then press the button to select it.

Selecting 1. SEQ. STORE calls up another screen with the text SEQUENCE over two

options: 1. AUTO STORE and 2. CLOSE STORE. Use the or button to
highlight the desired method of storing measurements (automatic or manual). Then

press the button to select it and resume display of the main memory screen.

Selecting 2. BATCH STORE calls up another screen with the text BATCH STORE over

two options: BATCH 1. TO 12. and SELECT BATCH 1. Use the or button to
change the value on the lower line from the default value of 1 to any number from 1 to

12. Then press the button. The display will show the text PLEASE WAIT as the
EMHT40 assembles stored measurements into a batch with the assigned number. When

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the batching process is finished, the unit will automatically resume display of the main
memory screen.

Selecting 3. CLEAR MEMORY calls up a display with the text CLEAR ADDRESS over

two 4-digit values. By alternating presses of the button (to view or change the

value of each digit) with presses of the button (to save settings and select the next
digit in turn), you can designate the first and last numbers of a sequence of memory
locations that you wish to erase. When you are satisfied with the memory location

settings, press the button. The EMHT40 will respond by showing the text PLEASE
WAIT as the EMHT40 deletes the data in the specified memory location(s). When the
deletion process is complete, the unit will automatically resume display of the main
memory screen.

7. Selecting 7. DATA OUTPUT calls up a screen with the text OUTPUT over two options:

1. SEQUENCE and 2. BATCH. Use the and button to navigate to the desired

option and then press the button to select it.

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Selecting 1. SEQUENCE calls up a screen with the text SEQUENCE over two lines:
START and a 4-digit value, and FINISH and a 4-digit value. By alternating presses of

the button (to view or change the value of each digit) with presses of the
button (to save settings and select the next digit in turn), you can designate the
number of the starting and ending memory locations to involve in batch data transfers

to a PC. When you are satisfied with the memory location settings, press the button
to resume display of the main memory screen.
Selecting 2. BATCH STORE calls up another screen with the text BATCH OUT over

two options: BATCH 1. TO 12. and SELECT BATCH 1. Use the or button to
change the value on the lower line from the default value of 1 to any number from 1 to

12, representing the number of the batch to be transferred to a PC. Then press the
button. The unit will automatically resume display of the main memory screen.

8. Selecting 8. CALIBRATION calls up a screen with the text CALIBRATION over three

lines: CAL. RANGE, AVG. DATA and CAL. DATA.

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The small up arrow will initially be under the + or – sign to the left of CAL. DATA. By

alternating presses of the button (to change the plus sign to a minus sign, or vice-

versa) with presses of the button (to change the values of the two CAL. DATA
digits), you can adjust the value of CAL. DATA until the CAL. RANGE and AVG.
DATA values compensate for consistent measurement errors caused by normal wear of

the impact device. When you are satisfied with the calibration adjustment, press the
button to resume display of the main memory screen.

9. Selecting 9. CONTRAST calls up a screen with the text CONTRAST over a bar graph.

Press the button to increase the contrast, or the button to decrease it. When

you are satisfied with the contrast setting, press the button to resume display of the
main memory screen.

10. Selecting 10. DEFAULT restores all settings to factory-default values.

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OPERATING INSTRUCTIONS

To power on the EMHT40, press the button. The typical display shown at left below will

appear. To power off the EMHT40, press and hold the button for at least 3 seconds.

Hint: Pressing the button with the measurement screen on the LCD changes the display
style from

to

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Note that this alternate display style sacrifices details (at the bottom of the LCD) for a larger
readout.

Before making a measurement, be sure the work piece complies with the weight, shape,
thickness and temperature guidelines detailed in the Setup Instructions.

To make a measurement:

1. Remove the black plastic collar from the shaft of the impact device.

2. Cock the plunger by sliding the top half of the shaft down toward the LCD.

3. Place the black plastic end of the unit on a flat part of the work piece. If the work piece
has a cylindrical or spherical inside or outside surface radius of less than 1.18 in.
(30mm) use the included support ring or acquire or devise a non-conventional support
ring as detailed in the Appendix.

4. Press the silver button at the end of the impact device shaft.

5. Read the measured hardness on the LCD.

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INTERFACING WITH A PC

The EMHT40 comes with a mini-disc containing 1) a program for transferring the contents of
the EMHT40’s memory to a PC for display, 2) drivers for the Windows8 (64- and 32-bit),
Windows7 (64- and 32-bit), Windows Vista (64- and 32-bit) and WindowsXP operating
systems, and 3) installation and operating instructions for the program and drivers.

The disc contains several folders and files containing the instructions needed to install the
drivers and to install and operate the program. Use the included USB cable to tether the
EMHT40 to the PC via the mini-USB jack on the top of the instrument (above the LCD).

You may need to reassign the numbers of your PC’s COM ports to enable the PC and the
EMHT40 to communicate using the USB cable.

SPECIFICATIONS

Measurement Accuracy: ±0.5%

Display Size, Type: 112×64 pixel LCD

Internal Memory Capacity: 1250 readings

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Auto Power Off Trigger: 2 minutes of control button inactivity

No.

Code

Type

Sketch

Remarks

Power Source: 3.7V rechargeable Li-ion-battery

Dimensions: 6.2 x 1.6 x 1 in. (158 x 41 x 26mm)

Weight: 4.2 oz. (120g)

OPERATING & MAINTENANCE TIPS

The EMHT40’s battery should be kept charged and charged frequently to avoid damaging it.
Using the AC adaptor, it takes about 4 hours to fully charge the battery from a completely
discharged state. Trickle-charging the battery from a PC’s USB port takes longer.

Over time, the tip of the impact body will abrade and reduce the EMHT40’s measurement
accuracy. Whenever measured values seem unusually large, calibrate the instrument by
following the procedure described on pages 16 and 17.

APPENDIX: Non-conventional support rings

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1

03-03.7

Z10-15

For cylindrical outside surfaces R10 to R15

2

03-03.8

Z14.5-30

For cylindrical outside surfaces R14.5 to R30

3

03-03.9

Z25-50

For cylindrical outside surfaces R25 to R50

4

03-03.10

HZ11-13

For cylindrical inside surfaces R11 to R13

5

03-03.11

HZ12.5-17

For cylindrical inside surfaces R12.5 to R17

6

03-03.12

HZ16.5-30

For cylindrical inside surfaces R16.5 to R30

7

03-03.13

K10-15

For spherical outside surfaces SR10 to SR15

8

03-03.14

K14.5-30

For spherical outside surfaces SR14.5 to SR30

9

03-03.15

HK11-13

For spherical inside surfaces SR11 to SR13

10

03-03.16

HK12.5-17

For spherical inside surfaces SR12.5 to SR17

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11

03-03.17

HK16.5-30

For spherical inside surfaces SR16.5～SR30

12

03-03.18

----

For cylindrical outside surfaces with a radius
adjustable from R10 to ∞

99 Washington Street
Melrose, MA 02176

Phone [phone]
Toll Free 1-800-517-8431

Visit us at www.TestEquipmentDepot.com

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