Dakota Ultrasonics PX7 Operating Manual

OPERATION MANUAL

P/N P

-

130

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0002

Rev

1.60,

January

200

8

DAKOTA ULTRASONICS MODEL PX-7 DL PRECISION THICKNESS GAUGE

Dakota Ultrasonics

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

PX-7 DL Ultrasonic Thickness Gauge

CONTENTS

INTRODU CTION
OPERATION

THE KEYPAD
THE DISPLAY
THE TRANSDUCER
MAKING MEASUREMENTS
CONDITION AND PREPARATION OF SURFACES
CALIBRATION
PX-7 DL MODES & FEATURES

RS232 PORT & DATA LOGGER
TRANSDUCER SELECTION
APPENDIX A: PRODUCT SPECIFICATIONS
APPENDIX B: APPLICATION NOTES

1
3
3
7

9
10
12
13
16
21
28
31
33

APPENDIX C: SOUND VELOCITIES OF COMMON MATERIALS
WARRANTY INFORMATION

35
37
42

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PX-7 DL Ultrasonic Thickness Gauge

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INTRODUCTION

The Dakota Ultrasonics model PX-7 DL is a precision Ultrasonic
Micrometer. Based on the same operating principles as SONAR, the PX-7
DL 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 DL, 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 DL Ultrasonic Thickness Gauge

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OPERATION

The PX-7 DL 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 DL 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 and the current file location and status. After
displaying the version number, the display will show ".0000" (or "0.000" if
using metric units), indicating the tool is ready for use.

The PX-7 DL 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 desi gned to conserve
battery life. If the tool is idle for 5 minutes, it will turn itself off.

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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 CAL key is used to enter and exit the PX-7 DL's calibration mode.
This mode is used to adjust the sound-velocity value that the PX-7 DL will
use when calculating thickness. The tool will either calculate the sound­velocity from a sample of the material being measured, or allow a known
velocity value to be entered directly. Refer to page 13 for an explanation of
the two CAL functions available.

The MODE key is used to toggle through the various features and
settings of the PX-7 DL ( alarm, diff, scan, gate, back light, and beeper ).

The MODE key is used in conjunction with the arrow and send keys to
enable/disable the features and settings. Refer to page 16 for a further
explanation of the different modes.

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The UP arrow key has three functions. When the PX-7 DL is in
calibration mode, this key is used to increase numeric values on the
display. An auto-repeat funct ion is built in, so that when the key is held
down, numeric values will increment at an increasing rate. When MODE is
activated, the UP arrow key scrolls through the various features and
settings of the PX-7 DL. When the data logging feature has been act ivated
by pressing the MEM key, the UP arrow is used to scroll through the
various files, storage locations, and functions of the data logger. Refer to
page 22 for further information regarding the use of the UP arrow key and
the data logger.

The DOWN arrow key has three functions. When the PX-7 DL 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 MODE is activated, the

DOWN arrow scrolls through the various features and settings of the PX- 7
DL. When the data logging feature has been activated by pressing the

MEM key, the UP arrow is used to scroll through the various files, storage
locations, and functions of the data logger. Refer to page 22 for further
information regarding the use of the DOWN arrow key and the data logger.

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The MEM key en ables/disables the data logging feature of the PX-7 DL.
This key is used in conjunction with the UP/DOWN arrows, SEND, AND
CLR keys (hi-lighted in green). The combination of these keys control the

data logging features of the PX-7 DL. Refer to the section on data logging
page 22.

The CLR key is specifically used with the data logging feature of the
PX-7 DL. This key clears the contents of an entire file, or individual storage
locations. The CLR key is also used to send an obstruct (ObSt) to an
individual storage location. The ObSt symbol would indicate that a the
user was unable to take a reading at a particular location. Refer to the
section on data logging page 22.

The SEND key is used for sending data to internal storage locations,
and external peripheral devices ( serial printer / computer ). The SEND key
is also used to select data logging functions in the PX-7 DL page 22.

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The Display

The numeric portion of the display 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 DL 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
DL 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 DL is having difficulty achieving a
stable measurement, and the thickness value displayed will most likely be
erroneous.

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When the IN symbol is on, the PX-7 DL is displaying a thickness value
in inches. The maximum thickness that can be displayed is 1.999 inches.

When the MM symbol is on, the PX- 7 DL is displaying a thickness value
in millimeters. If the displayed thickness exceeds 19.999 millimeters, the
decimal point will shift automatically to the right, allowing values up to 99.99
millimeters to be displayed.

When the IN symbol is on, in conjunction with the /µs symbol, the PX-7
DL is displaying a sound-velocity value in inches- per-microsecond.

When the M symbol is on, in conjunction with the /s symbol, the PX- 7
DL is displaying a sound-velocity value in meters-per-second.

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The Transducer

The transducer is the "business end" of the PX-7. It transmits and
receives ultrasonic sound waves that the PX-7 uses to calculate the
thickness of the material being mea sured. The transducer connects to the
PX-7 via the attached cable, and one coaxial connector.

The transducer must be used correctly in order for the PX-7 to produce
accurate, reliable measurements. Below is a short description of the

transducer, followed by instructions for its use.

The diagram above is a side view of a typical single element delay line
transducer. This delay line is fastened to the transducer with a retainer
ring. A drop of couplant is applied between the delay line and transducer
body. The transducer body contains one crystal element that is
responsible for conducting ultrasonic sound into and back from the material
being measured. When the transducer is placed against the material being
measured, it is the area directly beneath the delay line that is being
measured.