Dakota PX-7 User Manual

OPERATION MANUAL

P/N P

-

129

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0002

Rev

1.60

January

200

8

DAKOTA ULTRASONICS MODEL PX-7 PRECISION THICKNESS GAUGE

Copyright  2008 Dakota Ultrasonics. All rights reserved.

No part of this publication may be reproduced, translated into another
language, stored in a retrieval system, or transmitted in any form or by any
means; electronic, mechanical, photocopying, recording, or otherwise,
without the prior written consent of Dakota Ultrasonics.

Every precaution has been taken in the preparation of this publication.
Dakota Ultrasonics assumes no responsibility for errors or omissions.
Neither is any liability assumed for damages resulting from the use of
information contained herein.

Any brand or product names mentioned herein are used for identification
purposes only, and are trademarks or registered trademarks of their
respective holders.

1500 Green Hills Road, #107 Scotts Valley, CA 95066 USA

Tel [phone] Fax [phone]

www.dakotaultrasonics.com

CONTENTS

PX-7 Ultrasonic Thickness Gauge

INTRODU CTION
OPERATION

THE KEYPAD
THE DISPLAY
THE TRANSDUCER
MAKING MEASUREMENTS
CONDITION AND PREPARATION OF SURFACES
SELECTING MEASUREMENT MODE & THE LOCK MODE
CALIBRATION

SCAN MODE, ALARM MODE, DIFF MODE, RS232 PORT
TRANSDUCER SELECTION
APPENDIX A: PRODUCT SPECIFICATIONS
APPENDIX B: APPLICATION NOTES

1
3
3
7

9
10
12
13
14
17
22
25
27

APPENDIX C: SOUND VELOCITIES OF COMMON MATERIALS
WARRANTY INFORMATION

29
31

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.

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PX-7 Ultrasonic Thickness Gauge

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INTRODUCTION

The Dakota Ultrasonics model PX-7 is a precision Ultrasonic
Micrometer. Based on the same operating principles as SONAR, the PX-7
is capable of measuring the thickness of various materials with accuracy as

high as ± 0.0001 inches, or ± 0.001 millimeters. The principle 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.

This manual is presented in three sections. The first section covers
operation of the PX- 7, and explains the keypad controls and display. The
second section provides guidelines in selecting a transducer for a specific
application. The last section provides application notes and a table of
sound velocity values for various materials.

Dakota Ultrasonics maintains a customer support resource in order to
assist users with questions or difficulties not covered in this manual.
Customer support may be reached at any of the following:

• Dakota Ultrasonics, 1500 Green Hills Road, #107
Scotts Valley, CA 95066 USA

• Telephone: [phone]

• Facsimile: [phone]

• www.dakotaultrasonics.com

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PX-7 Ultrasonic Thickness Gauge

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OPERATION

The PX-7 interacts with the operator through the membrane keypad and
the LCD display. The functions of the various keys on the keypad are
detailed below, followed by an explanation of the display and its various
symbols.

The Keypad

This key is used to turn the PX-7 on and off. When the tool is turned
ON, it will first perform a brief display test by illuminating all of the
segments in the display. After one second, the tool will display the internal
software version number. After displaying the version number, the display
will show "0.0000" (or "0.000" if using metric units), indicating the tool is
ready for use.

The PX-7 is turned OFF by pressing the ON/OFF key. The tool has a
special memory that retains all of its settings even when the power is off.
The tool also features an auto-powerdown mode designed to conserve
battery life. If the tool is idle for 5 minutes, it will turn itself off.

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The CAL key is used to enter and exit the PX-7's calibration mode.
This mode is used to adjust the sound-velocity value that the PX-7 will use
when calculating thickness. The tool will either calculate the sound-velocity
from a sample of the material being measured, or allow a known velocity
value to be entered directly. Refer to page 14 for an explanation of the two
CAL functions available.

The IN/MM key is used to switch back and forth between English and
metric units. This key may be used at any time, whether the tool is

displaying a thickness (IN or MM) or a velocity value (IN/µs or M/s).

The UP arrow key has two functions. When the PX-7 is in calibration
mode, this key is used to increase numeric values on the display. An auto­repeat function is built in, so that when the key is held down, numeric

values will increment at an increasing rate. When the PX-7 is in
measurement mode, this key is used to select between three different

modes of measurement ( echo-echo, interface-echo, or auto ). Refer to
page 14 for an explanation of the calibration procedure and page 13 to
review the various measurement modes.

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The SCAN key switches the SCAN measurement mode on and off.
Refer to page 17 for an explanation of the SCAN measurement mode.

The DOWN arrow key has three functions. When the PX-7 is in the
CAL mode, this key is used to decrease numeric values on the display. An
auto-repeat function is built in, so that when the key is held down, numeric

values will decrement at an increasing rate. When the PX- 7 is not in
calibration mode, the DOWN arrow key switches the display backlight
between three available settings. OFF will be displayed when the backlight
is switched off. AUTO will be displayed when the backlight is set to
automatic mode, and ON will be displayed when the ba cklight is set to stay

on. In the AUTO setting, the backlight will illuminate while the PX-7 is
making a measurement and turn off after several seconds to conserve
battery life. Finally, if the DOWN arrow key is pressed and held down while

powering the PX-7 on, a LOC mode will be toggled on/off.

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The ALRM key has two functions. By holding down the ALRM key
when powering up the PX- 7, the audible beeper will be turned on or off

accordingly. After the unit has been turned on, pressing the ALRM key will
toggle the alarm mode to the on/off positions and allow the user to enter a
nominal thickness value. Refer to page 18 for details on how to use the
alarm feature.

The DIFF key is used to enable or disable the Differential mode and
allow the user to enter a nominal value as a comparison against actual
thickness measurements. Refer to page 19 for a complete explanation of
this feature.

The SEND key is used to send the cu rrently displayed thickness
measurement to an external storage device via the PX-7's RS232 port.

Refer to page 20 for an explanation of how to use this feature.

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The Display

The numeric portion of the displ ay consists of 4 complete digits
preceded by a leading "1", and is used to display numeric values, as well
as occasional simple words, to indicate the status of various settings.
When the PX-7 is displaying thickness measurements, the display will hold
the last value measured, until a new measurement is made. Additionally,
when the battery voltage is low, the entire display will begin to flash. When
this occurs, the batteries should be replaced.

These eight vertical bars form the Stability Indicator. When the PX-7 is
idle, only the left -most bar and the underline will be on. While the gauge is

taking a measurement, six or seven of the bars should be on. If fewer than
five bars are on, the PX-7 is having difficulty achieving a stable

measurement, and the thickness value displayed will most likely be
erroneous.