Dakota Ultrasonics CMXDL+ Operating Manual

Download

Page 1

OPERATION MANUAL

DAKOTA ULTRASONICS

DDLL+

CCMMX

Material & Coating Thickness Gauge

P/N P-172-0002 Rev 2.06, July 2010

Page 2

Page 3

CHAPTER ONE INTRODUCTION.......................................................................1

CHAPTER TWO QUICK STARTUP GUIDE........................................................2

CHAPTER THREE KEYBOA RD, MENU, & CONNECTOR REFERENCE.......24

CHAPTER FOUR PRINCIPALS OF ULTRASONIC ME ASUREMENT .............36

CHAPTER FIVE SELECTING THE MEASUREMENT MODE..........................41

CHAPTER SIX MAKING MEASUREMENTS.....................................................44

CHAPTER SEVEN USING THE DISPLAY OPTIONS.......................................60

CHAPTER EIGHT THRU PAINT MEASUREMENT TECHNIQUE....................91

CHAPTER NINE PULSE-ECHO COATING & COATING TECHNIQUES.........94

CHAPTER TEN ADDITIONAL FEATURES OF THE CMX

DL+

.........................109

CHAPTER ELEVEN DATA STORAGE – SETUP, EDIT, & VIEW FILES.......131

CHAPTER TWELVE SETUPS – CREATE, STORE, EDIT, & RECALL..........157

CHAPTER THIRTEEN USI NG THE UTILITY SOFTWARE.............................167

APPENDIX A - VELOCITY TABLE ...................................................................169

APPENDIX B - SETUP LIBRARY.....................................................................171

Page 4

Page 5

CHAPTER ONE INTRODUCTION

The Dakota Ultrasonics model CMX measures with extreme versatility. It has the ability to measure simultaneously measure coatings and material thicknesses while maintaining the ability to locate pits, flaws and defects in the material. Based on the same operating principles as SONAR, the CMX accuracy as high as ± 0.001 inches, or ± 0.01 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.

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:

DL+

is capable of measuring the thickness of various materials with

DL+

is an ultrasonic thickness gauge that

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

• Telephone: (831) 431- 9722

• Facsimile: (831) 431-9723

• http://www.dakotaultrasonics.com

1.1 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 rest solely with the user of the instrument. Other errors may occur from measuring coated materials where the coat ing 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.

Page 6

CHAPTER TWO QUICK STARTUP GUIDE

Turn the CMX keypad. When CMX

DL+

on and off using the switch located on the bottom right corner of the

DL+

is initially turned on, a flash logo and blinking lights will be displayed, followed by attempting to identify the transducer (probe) currently plugged into the gauge. The CMX that attempts to identify special transducers with this built in feature. If the CMX

DL+

is equipped with an “Auto Probe Recognition” feature

DL+

doesn’t find a transducer equipped with this feature, the user will be advanced to a list of transducers requiring the user to select a specific transducer type. The following sections outline each scenario. Note: This section is primarily written as a basic startup guide only.

2.1 CMX

DL+

Overview

Page 7

DL+

CMX

High Performance Material & Coating Thickness Gauge

In order to understand how to operate the CMX understanding of what it is we’re looking at exactly. The CMX

DL+

, it’s best to start off with an

DL+

has a lot of great features and tools that will prove to be a huge benefit for the variety of applications you’re constantly facing on a continual basis. Let’s have a brief look at the screens you’ll be looking at most often:

A. Repeatability/Stability Indicator – This indicator should be commonly used

in conjunction with the digital thickness values displayed. When all the vertical bars are fully illuminated and the last digit on the digital thickness value is stable, the CMX

DL+

is reliably measuring the same value 3 to 200 times per

second, depending on which measurement mode and features are enabled. B. Battery Icon – Indicates the amount of battery life the CMX C. Velocity – The material velocity value the CMX

DL+

is currently using or

DL+

has remaining.

calibrated for. Displayed in both English or Metric units, depending on the

what units the gauge is set for. D. Feature Status Bar – Indicates the features currently enabled and in use in

the following order:

• Measurement Mode

• Differential Mode

• High Speed Scan Mode

• Alarm Mode

• Gain Setting

E. Digital Material Thickness Value – Extra large font size for viewing ease.

Page 8

Dakota Ultrasonics

F. Scan Bar – Another view of material thickness in a deflection style horizontal

bar. This is a visual tool that would enable the user the ability to see thickness changes during high speed scans from flaws and pits.

G. Units – The current measurement units being used (English, Metric). H. Digital Material Thickness Value – Smaller font size when the B-Scan

display view is enabled.

I. Coating Thickness Value – Displays the actual thickness of any coating

adhered to a metallic material surface (PECT Mode), or a coating adhered to a non-metallic surface (CT Mode).

J. Minimum Material Thickness – Part of the Alarm feature. Displays the

minimum thickness value found during a scan.

K. Maximum Material Thickness – Part of the Alarm feature. Displays the

maximum thickness value found during a scan.

L. B-Scan Display – Cross section view of the material. Provides the user with

graphical view of the opposite/blind surface (i.e. inside pipe wall surface), to give the user some idea of the condition, or integrity of the material being tested.

M. RF A-Scan Display – The actual sound wave reflection that is returned fr om

the detection of the opposite surface of the material being measured. In this view, the entire sine wave is displayed, showing both the positive and negative half cycles from the detection/reflection. This view is commonly used to initially “see the b ig picture” and make fine adjustments to the scope settings, prior to selecting another view option.

N. Hot Menu items – We call this menu section our “hot menu”, as these items

are the most commonly adjusted features, requiring quick access from the user. They can be displayed and scrolled by pressing the MEAS key at anytime. The ESC key is used in conjunction with MEAS key to reverse the direction scrolled.

O. Reference Note – When the “hot menu” items are displayed/activated, the

base material thickness valu e shown at reference point “O”. However, when the “hot menu” items have been deactivated, the current base material velocity value is displayed, as shown in reference point “P”. When the “hot menus” are deactivated, the entire “hot menu” section becomes a multiple measurement display area, allowing the user to simultaneously view: base material, coating, and base material minimum/maximum thickness values dynamically, as shown in reference point “R”.

P. Reference Note – Please refer to “O”, for a detailed explanation. Q. RECT A-Scan Display – The actual sound wave reflection that is returned

from the detection of the opposite surface of the material being measured. In this view, only half of the sine wave is being displayed (positive or negative). This view is commonly referred, and used as a “flaw detection” mode, once the user made all the necessary adjustments using the RF mode (refer to M).

Page 9

DL+

CMX

High Performance Material & Coating Thickness Gauge

2.2 Auto Probe Recognition

When the CMX the transducer plugged into the gauge can be recognized. The steps that follow assume the CMX

DL+

is initially powered up, the gauge will automatically check to see if

DL+

recognized the probe type:

Probe Automatically Recognized

1) Press the OK key once to use the identified probe, or ESC to display a list of

optional transducers. Note: if the CMX

DL+

recognizes a specific

transducer, the user should always select OK to use the identified probe. The only time an alternative probe should be selected from a list is if the user switched probes following initial power up and recognition.

2) Assuming the CMX the CMX

DL+

will advance to a Zero Probe menu. If the transducer was

DL++

recognized the probe and the OK key was pressed,

identified as a special transducer capable of measuring coating thickness, a menu will be displayed allowing the user the ability to toggle the coating thickness display on/off as follows:

Page 10

Dakota Ultrasonics

3) Press the UP and DOWN arrow keys to toggle the coating option on/off.

4) Wipe all couplant from the transducer face and advance to the Probe Zero

& Calibration section outlined below.

2.3 Selecting the Transducer Type

If the CMX will be required to select a type from a predefined list of types by diameter and frequency. By selecting a transducer type from a predefined list, the CMX recall specific properties about the transducer. Note: Once the transducer has been

selected, the CMX is powered on/off. The type will only change if the user physically selects another transducer type from the list, or selects a previously saved setup. However, the

CMX

powered up. You’ll notice that the probe type previously selected will be highlighted every time the probe type screen is displayed. Use the following steps to select your transducer type:

DL+

does not identify a specific transducer type on initial power up, the user

DL+

will store and recall this transducer type every time the CMX

DL+

will continue to take you through these steps each time the gauge is

DL+

can

DL+

Page 11

DL+

CMX

High Performance Material & Coating Thickness Gauge

Selecting the Transducer Type

1) Press the OK or ESC keys to display the factory list of transducer types (by diameter and frequency ).

2) Press the UP and DOWN arrow keys to scroll through the transducer list until the appropriate type is highlighted.

Page 12

Dakota Ultrasonics

3) Press the ENTER key to select the transducer type and display overwrite existing probe screen.

4) Press the OK key to overwrite the existing probe type with the newly selected probe type. The zero probe screen will be displayed. Proceed to

the zero probe section that follows.

2.4 Probe Zero & Calibration

The next steps are to perform a probe zero and calibrate the CMX and transducer being used. If the sound velocity is unknown, the CMX calibrated to a known thickness sample. This demo will briefly explain both of these techniques.

The CMX

DL+

is equipped with two zero options:

1) Off Block Zero (Automatic Probe Zero) – When this feature is enabled the

DL+

CMX

will do an electronic zero automatically, eliminating the need for a zero

disk or block.

2) On Block Zero (Manual Probe Zero) – When this feature is enabled the transducer must be placed on the probe zero disk (battery cover located on the

top of the unit.

Note: Transducers of the same type will have very slight mechanical and electrical variations. If it’s discovered that the linearity is off following an initial auto probe zero

and extreme accuracy is required, a manual zero should be performed followed by an auto zero. This will adjust and eliminate any error. This is only required if it’s discovered the transducer is non-linear following an initial auto probe zero.

The procedures are outlined as follows:

DL+

to the material

DL+

can be

Page 13

DL+

CMX

High Performance Material & Coating Thickness Gauge

Performing an Auto Probe Zero (Off Block)

Coating Probe Identified Coating Probe Not Identified

1) Be sure all couplant has been removed from the face of the transducer.

2) Press the OK key to perform the automatic probe zero, or ESC key to cancel the zero operation.

Coating Probe Identified Coating Probe Not Identified

3) The screens illustrated above will be briefly displayed followed by the main measurement screen. The CMX

DL+

is ready to be calibrated.

Page 14

Dakota Ultrasonics

Performing a Manual Probe Zero (On Block)

Note: When the zero probe option is set to manual, the probe zero disk

(battery cap) located on the top of the gauge, will be used as a zero standard and the warning screen illustrated above will be displayed.

1) Press the OK or ESC keys to enter the main measurement screen and begin the manual zero process.

2) Apply a drop of couplant on the transducer and place the transducer in steady contact with the probe zero disk, and obtain a steady reading.

3) Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the PRB menu is highlighted and displaying the submenu items.

4) Press the UP and DOWN arrow keys to scroll through the sub menu items until ZERO PROBE is highlighted.

Page 15

DL+

CMX

High Performance Material & Coating Thickness Gauge

Coating Probe Identified Coating Probe Not Identified

5) Press the ENTER key to display the confirmation screen.

6) If a coating transducer was identified use the UP and DOWN arrow keys to toggle coating on/off.

7) Press the OK key to complete the probe zero function, or ESC key to cancel the probe zero function.

8) Remove the transducer from the probe zero disk, and proceed to the calibration section.

Note: The value that is displayed will change depending on the current velocity setting in the CMX

DL+

. Disregard the number that is displayed. It is not

important. What is important is accurately performing the steps outlined above

to insure reliability of the probe zero calculation.

One Point Material Calibration

For the purposes of this quick start section, we’ll only be covering the most common one point calibration option to determine the sound velocity of the test material. It would be very handy to carry a set of mechanical calipers to use in conjunction with the CMX

DL+

for calibration in the field:

Page 16

Dakota Ultrasonics

Using a Known Thickness

Note: Be sure that the probe zero procedure has been performed prior to

performing this calibration procedure.

1) Physically measure an exact sample of the material or a location directly on the material to be measured using a set of calipers or a digital micrometer.

2) Apply a drop of couplant on the transducer and place the transducer in steady contact with the sample or actual test material. Be sure that the reading is stable and the repeatability indicator, in the top left corner of the display, is fully lit and stable. Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the CAL menu is highlighted and displaying the submenu items.

3) Use the UP and DOWN arrow keys to scroll through the sub menu items until MATL 1PT is highlighted.

Page 17

DL+

CMX

High Performance Material & Coating Thickness Gauge

4) Press the ENTER key to display the Digits Edit Box.

5) Press the UP and DOWN arrow keys to scroll the highlighted value.

6) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

7) Repeat steps 5 & 6 until the known thickness value is correctly displayed.

8) Press the OK key to calculate the velocity and return to the menu screen, or ESC to cancel the one point calibration.

9) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Note: CHECK YOUR CALIBRATION! Place the transducer back on the calibration point. The thickness reading should now match the known

thickness. If the thickness is not correct, repeat the steps above.

2.5 Zero Coating

In order to account for very slight electronic differences in transducers of the same type, frequency, and diameter, the CMX feature. This enables the CMX

DL+

to obtain very accurate readings on coatings,

DL+

has been equipped with a “zero coating”

eliminating potential errors incurred from slight differences in the manufacturing processes. The procedure is outlined below:

Page 18

Dakota Ultrasonics

Performing a Coating Zero

1) Press the MULTI MODE key once to activate th e measurement mode options.

2) Use the UP and DOWN arrow keys to scroll through the sub menu items until Coating Only (CT) mode is highlighted.

3) Press the ENTER key to select the measurement mode and return to the measurement screen.

4) Apply a drop of couplant on the transducer and place the transducer in steady contact with the probe zero disk (battery cover) and obtain a steady reading.

Note: The coating measurement displayed will potentially be a value greater or less than 0.

5) Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the PRB menu is highlighted and displaying the submenu items.

Page 19

DL+

CMX

High Performance Material & Coating Thickness Gauge

6) Use the UP and DOWN arrow keys to scroll through the sub menu items until ZERO COATING is highlighted.

7) Press the ENTER key to display the confirmation screen.

8) Press the OK key to zero the coating and return to the PRB menu, or ESC to cancel the coating zero process.

9) Press the MULTI MODE key once to activate the measurement mode options.

10) Use the UP and DOWN arrow keys to scroll through the sub menu items until Coating On (PECT) is highlighted.

11) Press the ENTER key to select the measurement mode and return to the measurement screen, and begin taking readings.

2.6 Coating Calibration

The CMX m/sec). This will be very close to the most common coating material velocities used in the field. If the velocity of the coating is known, and different than the above default setting, the user can simply enter the coating velocity into the CMX However, if the velocity is unknown, the CMX coating sample/type using the 1pt calibration option in PECT (pulse-echo coating) mode, or a two point calibration is CT (coating only) mode. For the purpose of this

DL+

has been preset to a default coating velocity of 0.0850 in/µsec (2159

DL+

can also be calibrated to a specific

Page 20

Dakota Ultrasonics

quick start section only the 1pt option PECT (pulse-echo coating) mode will be covered. Refer to the calibration section of the manual for a complete explanation on the coating calibration options. The following steps below outline the necessary steps to either set the velocity of the coating, or perform a one point calibration to calculate the coating velocity:

Known Coating Velocity

If the coating velocity is known, the user may wish to simply enter the velocity number into the CMX

DL+

, rather than have the CMX

DL+

calculate the velocity value using a known thickness on a coating sample. The steps for entering the velocity are outlined below:

Using a Known Coating Velocity

1) Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the CAL menu is highlighted and displaying the submenu items.

2) Use the UP and DOWN arrow keys to scroll through the sub menu items until COATING VEL is highlighted.

3) Press the ENTER key to display the Digits Edit Box.

4) Press the UP and DOWN arrow keys to scroll the highlighted value.

5) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

Page 21

DL+

CMX

High Performance Material & Coating Thickness Gauge

6) Repeat steps 4 & 5 until the velocity number is correctly displayed.

7) Press the OK key to set the coating velocity and return to the menu screen, or ESC to cancel entering the coating velocity.

8) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Known Coating Thickness

When the exact velocity of a coating is unknown, the user has the option of performing a one point calibration on a sample of the coating with a known thickness to determine the sound velocity. It would be very handy to carry a set of mechanical calipers to use in conjunction with the CMX

DL+

for calibration in the field:

Using a Coating Sample to Calibrate

1) Physically measure a location on a coating sample using a set of calipers or a digital micrometer .

Page 22

Dakota Ultrasonics

Important Note: In PECT (pulse-echo coating) mode, the coating sample must be coupled to metal in order to calibrate successfully. Simply place a drop of

couplant on a piece of metal, lay the coating sample over the couplant on the metal and proceed to step 2.

2) Apply a drop of couplant on the transducer and place the transducer in steady contact with the coating (on metal) sample or actual test material. Be sure that the reading is stable and the repeatability indicator, in the top left corner of the display, is fully lit and stable. Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the CAL menu is highlighted

and displaying the submenu items.

3) Use the UP and DOWN arrow keys to scroll through the sub menu items until COATING 1PT is highlighted.

4) Press the ENTER key to display the Digits Edit Box.

5) Press the UP and DOWN arrow keys to scroll the highlighted value.

6) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

7) Repeat steps 5 & 6 until the known thickness value is correctly displayed.

Page 23

DL+

CMX

High Performance Material & Coating Thickness Gauge

8) Press the OK key to calculate the coating velocity and return to the menu screen, or ESC to cancel the one point calibration.

9) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Note: CHECK YOUR CALIBRATION! Place the transducer back on the calibration point. The coating thickness reading should now match the known coating thickness sample. If the thickness is not correct, repeat the steps above.

2.7 Measure

The CMX options, each with a specific purpose – Digits, RF, RECT, & B-Scan. The steps below outline how to toggle between the different view mode options:

DL+

is now ready to measure. There are four different measurement view

Selecting the Measurement View Option

1) Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the DISP menu is highlighted and displaying the submenu items.

Page 24

Dakota Ultrasonics

2) Use the UP and DOWN arrow keys to scroll through the sub menu items

until VIEW is highlighted.

3) Use the LEFT and RIGHT arrow keys to scroll the view options.

4) Once the view is displayed, press the MEAS key to return to measurement

mode.

DIGITS: Displays the digital thickness value using a large font size. This view is useful when the CMX

DL+

is being used as a basic thickness gauge.

RF: Displays the actual waveform signal, much like an oscilloscope, from the reflection of the opposite surface, pit, flaw, crack or void. This view shows both the positive and negative peaks, and is often used to fine tune the scope settings, prior to inspection.

RECT: Displays a half waveform signal, either positive or negative, from the reflection of the opposite surface, pit, flaw, crack or void. The user can select the polarity or “phase” displayed. This is typically determined by first using RF view to select the most optimal polarity “phase”, to fine tune the scopes settings. The RECT view is commonly used as the primary “flaw detection” view.

BSCAN: The Time Based B-Scan provides the user with a cross sectional view of the material being tested. This mode is useful when there is concern regarding the

profile of the blind surface. This can also be a useful view when scanning for pits and flaws.

Once the view has been selected according to the application requirements, the Delay and Range of the screen will potentially need to be adjusted, if the view has been set to RF or RECT. Alternatively, if BSCAN was selected, the B-Start and B- Depth settings will need to be adjusted. These settings serve the same purpose, with only differences in terminology. The Delay the same as B-Start, and the Range is the same as B-Depth. Therefore, these items will be grouped together for the duration of this manual, as follows: Delay (B-Start) and Range (B-Depth). Use the following steps to adjust these settings directly from the measurement screen as follows:

Note: The Delay (B-Start) and Range (B-Depth) are also used to adjust the parameters of Scan Bar.

Page 25

DL+

CMX

High Performance Material & Coating Thickness Gauge

Adjusting Delay (B-Start) & Range (B-DEPTH)

1) Press the MEAS key once to activate the measure menu items. Press the MEAS key multiple times to move right and the ESC key multiple times to

move left, until the either the DELAY (START) or RANGE (DEPTH) cell is highlighted.

2) Use the UP, DOWN, LEFT, or RIGHT arrow keys to scroll the DELAY (START) and RANGE (DEPTH) values.

3) Repeat steps 1 & 2 until the range is correctly being displayed.

Alternatively, the DELAY (START) and RANGE (DEPTH) values can be changed using the Digit Edit Box as follows:

4) Press the MEAS key once to activate measure menu items. Press the MEAS key multiple times to move right and the ESC key multiple times to move left, until the either the DELAY (START) or RANGE (DEPTH) cell is highlighted.

Page 26

Dakota Ultrasonics

1) Press the ENTER key to display the digits edit box.

2) Press the UP and DOWN arrow keys to scroll the highlighted value.

3) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

4) Repeat steps 3 & 4 until the DELAY (START) or RANGE (DEPTH) value is correctly displayed.

5) Press the OK key to set the DELAY (START) and WIDTH (DEPTH) value and return to the measure screen, or ESC to cancel entering the DELAY (START) or WIDTH (DEPTH) value.

6) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Note: The DELAY (START) & WIDTH (DEPTH) can also be adjusted from the tabbed menu item DISP. However, using the hot menu keys is the easiest

method.

Page 27

DL+

CMX

High Performance Material & Coating Thickness Gauge

RF View Rectified (RECT) View

BSCAN View DIGITS View

In the upper left corner of each of the display photos above, is the repeatability indicator. The repeatability indicator is represented by six vertical bars and represents how repeatable the measurements are. In regular measurement mode, the CMX 200 measurements a second. If the coating mode option is activated, the CMX makes 3 measurements a second in regular measurement mode and 65 measurements a second in scan mode. When the CMX vertical bar will be displayed. However, when the CMX four or five of the bars should be displayed on the repeatability indicator. If fewer than four bars are showing, the CMX measurement and the thickness value displayed is potentially unstable.

DL+

makes 8 measurements a second. In scan mode, the CMX

DL+

is idle, only the left

DL+

is making a measurement,

DL+

is having difficulty achieving a stable

DL+

makes

DL+

Page 28

CHAPTER THREE KEYBOARD, MENU, & CONNECTOR REFERENCE

3.1 Menu Key (Operation & Sub Menus)

The Menu key activates the primary menu structure containing 8 menu tab groups. These tab groups then contain sub menu items, or functions. The sub menu items have been organized in tab groups according to how closely they are related to the individual tab group names. Let’s first get familiar with how to move around in these tabs before continuing on to the sub menu functions. This procedure is outlined below:

Page 29

DL+

CMX

High Performance Material & Coating Thickness Gauge

Activating and Getting Around in the Menu Items

1) Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right, and the ESC key multiple times to tab left

until the desired tab group is highlighted and displaying the submenu items. The tab groups are illustrated above (A).

Now that you’re familiar with activating and moving amongst the tab groups, let’s have a look at how to move around in the sub menu items as follows:

Getting Around in the Sub Menu Items

1) Use the UP and DOWN arrow keys to scroll through the sub menu items until the desired function is highlighted. The sub menu items are illustrated in the diagram above (B).

2) Depending on which function is highlighted, use the LEFT, RIGHT, and Enter keys to scroll the options or activate the Digit Edit and List Box

options.

The sections to follow will provide the user with an explanation of the sub menu functions:

Page 30

Dakota Ultrasonics

3.2 Probe – Menu

ZERO PROBE: The CMX

micrometer is zeroed. If the CMX made using the CMX equipped with an optional automatic or manual zero feature. Refer to the section on page 48, for an explanation of this important procedure.

ZERO COATING: In order to account for very slight electronic differences in transducers of the same type, frequency, and diameter, the CMX

equipped with a “zero coating” feature. This enables the CMX accurate readings on coatings, eliminatin g potential errors incurred from slight differences in the manufacturing processes. Refer to the section on page 48, for a detailed explanation.

TYPE: Enables the user to select the type of transducer bein g used from a chart of transducer types. This provides increased linearity between transducers. Refer to page 44 for a further explanation.

FLAW MODE: Activates the flaw detection mode and view. This feature is for use with single element angle beam transducers and used as a general prove-up flaw inspection mode. Refer to page 120 for a further explanation.

DL+

is zeroed in much the same way that a mechanical

DL+

may be in error by some fixed value. The CMX

is not zeroed correctly, all of the measurements

DL+

has been

to obtain very

3.3 CAL – Menu

MAT: Select the material velocity from a chart of basic material types when a known

sample thickness, or material velocity cannot be obtained. Refer to page 57 for further info.

MATL 1PT: Performs a single point calibration. This option allows the user to automatically calculat e the velocity by entering a known sample thickness. Refer to

page 54 for further info.

Page 31

DL+

CMX

High Performance Material & Coating Thickness Gauge

MATL 2PT: Performs a two-point calibration. This option allows the user to automatically calculate the velocity by entering a second known sample thickness. Refer to page 56 for further info.

VELOCITY: Function to calibrate the CMX

DL+

by setting the velocity to a known material velocity. Refer to page 52 for further info. COATING 1PT: Performs a single point coating calibration. This option allows the user to automatically calculate the velocity by measuring a known coating sample thickness. Refer to page 104 for further info. COATING 2PT: Performs a two-point coating calibration. This option allows the user to automatically calculate the velocity by entering a second known coating

sample thickness. Refer to page 104 for further info.

COATING VEL: F unction to calibrate the CMX

DL+

to a specific coating material type

by entering a coating velocity. Refer to page 16 or page 98 for further info.

3.4 DISP (display) – Menu

VIEW: Selectable BSCAN (cross section), and DIGITS (large digits) views. Refer to

page 61 for further info. DELAY (B-START): Provides the user the ability to change the start position of the

B-SCAN view. Refer to page 69 for further info. RANGE (B-DEPTH) : Provides the user the ability to change the overall depth of the

viewable measurement area. It functions a lot like a zoom on a camera. Refer to page 71 for further info.

B-SCAN SPEED: (color version only) – Controls the speed of the time based B- Scan with an arbitrary scale of 0-10, with 10 being the fastest scrolling speed. Default speed set at 6. Refer to page 73 for further info.

UNITS: Toggle between English or Metric units. The readout will change from inches to millimeters. BACKLIGHT: Selectable OFF, ON, AUTO, or INVERT backlight option.

Note: Color version uses an AMOLED display, and ‘Brightness’ is substituted for Backlight as the menu item label, with an arbitrary scale of 1-20, with the brightest setting at 20. Refer to page 115 for further info.

CONTRAST: Adjustable display contrast for variable light conditions.

Note: This menu item is eliminated in the color version.

Page 32

Dakota Ultrasonics

VIEW: (color version only) – Provides the user with 12 different color schemes to select from. There are two schemes for each main color option. Refer to page 117 for further info.

DIM: (color version only) – Allows the user to conserve battery life by diming the display after idle for a specific amount of time – OFF, 30, 60, 90, 120 seconds. Once dimmed, a single press of any key will restore the screen brightness. Refer to page 118 for further info.

RECT WAVE: This option provides the user an outlined or filled view option when the display setting is in RECT (rectified) wave mode only. Refer to page 123 for further info.

DETECT MARK: Selectable graphics option for the point of detection on th e waveform: Line, Box, Dots, None. Offers the user a graphics preference on how they prefer to view the detection on the waveform.

3.5 TUNE – Menu

MEASURE MODE: Toggles a variety of unique measurement modes for different

application requirements: Coating Off (P-E), Coating On (PECT), Temp Comp (PETP), Thru Coat (E-E), Thru Verify (E-EV), Coating Only (CT). Refer to page 37 for further info.

POLARITY: The CMX feature toggles which stroke of the cycle the crossing detection uses, either positive or negative. Refer to page 125 for further info.

PULSE: The CMX resolution applications. The pulse width refers to the duration of time the pulser is on. The options are Spike, Thin, and Wide. Refer to page 127 for a further explanation.

PULSER VOLTAGE: This feature offers a 50 volt cut/boost to the pulser. The standard setting is 150 volts. This enables the CMX for difficult material types, or increased resolution on noisy materials. Refer to page 128 for a further explanation.

DAMPING: (color version only) – Provides the user with multiple input impedances to match the impedance of the transducer, and optimized overall transducer performance. Refer to page 119 for further info.

DL+

operates on a zero crossing detection principle. This

DL+

has an adjustable pulse width for both high penetration and

DL+

to offer greater penetration

Page 33

CMX

DL+

High Performance Material & Coating Thickness Gauge

ATTN: This feature is a 20dB attenuator, as well as a 20dB amplifier. The primary purpose is to is to offer further flexibility to the CMX

DL+

, by either cutting or boosting signal strength. In instances where the 60 dB range is not enough, or too much, this feature allows you to increase/decrease the amplifier strength by a power of 10 or (20dB). The standard setting is zero, which is an arbitrary value at a constant attenuation. The attenuation value is added to the gain value. Therefore, if the attenuator is increased to 20dB, this value is added to the value of the gain setting. Refer to page 129 for a further explanation.

GAIN: The CMX

DL+

has 100dB gain range from (-30 to 70 dB), used in conjunction

with the attenuator feature above. This feature is used to increase/decrease the power or amplitude of the signal. This might easily be considered as similar to turning the volume up or down on a stereo receiver. Refer to page 74 for further info.

AGC: This an automatic gain control used in E-E (echo-echo), and E-EV (echo-echo verify). The CMX

DL+

is equipped with an automatic gain control when operating in -E (echo-echo), and E-EV (echo-echo verify) modes only. This feature automatically increases/decreases the power or amplitude of the signal, to an optimal input to output signal ratio. This might easily be considered as similar to turning the volume up or down on a stereo receiver. Alternatively, the AGC can be manually controlled. The CMX

DL+

is equipped with manual override, using an arbitrary range of 1-20 clicks. The higher the number the better the dynamic gain range, and visa versa. Refer to page 74 for further info.

3.6 GT1 – Menu

GATE1: Gates allow the user to view a specific measurement range, or sections of

the waveform, and ignore others. The Gate1 feature adjusts the start of the gate, according to time/distance. Gate 1 can be used in all pulse-echo and echo-echo measurement modes. Refer to page 83 for further info.

GATE1 WIDTH: This feature allows the user to set the overall width of the gate, in terms of distance, from the starting value of Gate1. Refer to page 83 for further info. THRESHOLD1: Enables the user to set the sensitivity level of Gate1. The amplitude of the signal must reach or exceed the threshold level before a measurement is

detected. Refer to page 83 for further info.

3.7 GT2 – Menu

Page 34

Dakota Ultrasonics

GATE2 WIDTH: This feature allows the user to set the overall width of the gate, in terms of distance, from the starting value of HoldOff2. Refer to page 83 for further info.

HOLDOFF 2: Provides the user with the ability to delay the starting point of Gate2, a specific distance from the first detection point found inside of the boundaries of the

Gate 1 settings. If no detection is found, the Gate1 width value is used as a starting value for Gate2. Refer to page 83 for further info.

THRESHOLD2: Enables the user to set the sensitivity level of Gate2. The amplitude of the signal must reach or exceed the threshold level before a measurement is detected. Refer to page 83 for further info.

3.8 GT3 – Menu

GATE3 WIDTH: This feature allows the user to set the overall width of the gate, in

terms of distance, from the starting value of HoldOff3. Refer to page 83 for further info.

HOLDOFF 3: Provides the user with the ability to delay the starting point of Gate3, a specific distance from the first detection point found inside of the boundaries of the Gate 2 settings. If no detection is found, the Gate2 width value is used as a starting value for Gate3. Refer to page 83 for further info.

THRESHOLD3: Enables the user to set the sensitivity level of Gate3. The amplitude of the signal must reach or exceed the threshold level before a measurement is

detected. Refer to page 83 for further info.

3.9 SETUP – Menu

OPEN: Displays a list of factory and user defined setups currently stored in memory.

These setups can be recalled and used at any time. Refer to page 157 for further info.

Page 35

DL+

CMX

High Performance Material & Coating Thickness Gauge

SAVE: Provides the user with the ability to save a custom setup that has been modified or created by the user. Refer to page 159 for further info.

DELETE: Provides the user with the ability to delete specific setups previously save in memory. Refer to page 163 for further info.

DEFAULT SETUP : Loads a basic default setup. Use only as a last resort when the setups in the CMX

DL+

have been corrupted and a computer is not accessible. Refer

to page 164 for further info. LANGUAGE: Provides the user the ability to select different languages for the

DL+

CMX

. Refer to page 166 for further info.

3.10 DATA – Menu

NEW: Allows the user the ability to create a new alpha numeric grid, or sequential

log file with auto identifiers. It is equipped with custom parameters, rows, and columns depending on the user’s application reporting requirements. Refer to page 132 for further info.

EDIT: Gives the user the ability to change parameters of grid or sequential file previously saved. Note: Pre-defined coordinates cannot be changed once they have

been created. Refer to page 150 for further info. OPEN: This function provides the user with the ability to recall grids or sequential log files that currently exist in memory, from a list of grids. Refer to page 152 for further

info. CLOSE: Provides the user the ability to close a currently opened grid or sequential

log file. Refer to page 154 for further info. DELETE ONE FILE: This function provides the user with the ability to delete one individual grid or sequential log file from a list of multiple grids/files previously saved

in memory. Refer to page 147 for further info. DELETE ALL DATA : This function provides the user with the ability to delete all files

currently stored in memory. Refer to page 148 for further info.

3.11 UTIL (utilities) – Menu

Page 36

Dakota Ultrasonics

AUTO FIND: Automatically locates the detection point if the measurement is out of the viewable display area. Refer to page 109 for further info. SCAN MODE: This function enables a hi speed scan mode that increases the overall sample rate from 65 to 200 measurements per second, depending on the

current measurement mode used. Refer to page 109 for further info.

ALARM: Toggles alarm mode on , off, or audible. Refer to page 111 for further info. ALARM HIGH: Gives the user the ability to set the HI limit parameter. If the

measurement exceeds this value, a red light will illuminate and sound the internal beeper. Refer to page 111 for further info.

ALARM LOW : Gives the user the ability to set the LO limit parameter. If the measurement falls below this value, a red light will illuminate and sound the internal beeper. Refer to page 111 for further info.

DIFFERENTIAL: Gives the user the ability to set a nominal value and the CMX

DL+

will display +/ - the difference from the nominal value entered. Refer to page 113 for further info.

3.12 XFER (transfer) – Menu

BACKUP SETUPS : Enables the user the ability to backup the setups currently

stored in the CMX

DakView software for a complete electronic manual. RESTORE SETUPS : Enables the user the ability to restore the setups currently

saved on a PC to an CMX

DakView software for a complete electronic manual. BACKUP DATA : Enables the user the ability to backup grids or sequential log files

currently stored in the CMX

DL+

CMX

DakView software for a complete electronic manual.

RESTORE DATA : Enables the user the ability to restore grids or sequential log files

currently saved on a PC to an CMX

DL+

CMX

DakView software for a complete electronic manual.

ABOUT: Provides the user with Dakota Ultrasonics contact information and the

DL+

CMX

software version. Refer the Dakota Ultrasonics web site for information on

the latest firmware versions available for download.

DL+

to a PC via RS232 port. Refer the help section of the CMX

DL+

via RS232 port. Refer the help section of the CMX

DL+

to a PC via RS232 port. Refer the help section of the

DL+

via RS232 port. Refer the help section of the

DL+

Page 37

DL+

CMX

High Performance Material & Coating Thickness Gauge

3.13 CLR (clear) Key

The primary functions of the CLR key, is to clear a measurement from a grid or sequential log files cell location or set obstruct, and backspace in an Alpha Edit Box. If a user has already saved a measurement and B-Scan to a cell location, use this key to clear the measurement at any time.

3.14 MEAS (measurement mode) Key

The MEAS key puts the CMX the user has a complete view of the LCD.

DL+

into it’s primary mode of operation. In this mode,

3.15 OK Key

The primary function of the OK key is confirmation of a change or selection. The OK key also toggles the Hot Menu area, while in measurement mode, to a large digits

display area. If the CMX

DL+

is displaying a grid log, the OK key toggles an advance

to row number option.

3.16 ESC Key

The ESC key is used in the MENU, MEAS, and EDIT functions as a back or escape function. If the CMX display options: Digits, RF, RECT, and B-Scan views.

DL+

is displaying a grid or sequential log, the OK key toggles the

3.17 Arrow Keys

The Arrow Keys are used to navigate through the menus, increase/decrease values, and toggle specific function keys.

3.18 ENTER key

Page 38

Dakota Ultrasonics

The ENTER key is u sed in the overall menu selection process, to activate list and edit boxes, display and save measurements to grid or sequential files locations.

3.19 MULTI MODE Key

The MULTI MODE key opens a measurement mode screen, listing all the modes that are available to the transducer specifically selected, or autodetected. The modes can

be all or a combination of the entire set of modes the CMX which transducer is being used as follows: Coating Off (P-E), Coating On (PECT),

Temp Comp (PETP), Thru Coat (E-E), Thru Coat Verify (E-EV), and Coating Only (CT).

DL+

offers, depending on

3.20 ON/OFF Key

The ON/OFF key simply powers the unit either ON or OFF. Note: Unit will automatically power off when idle for 5 minutes. All current settings are automatically

saved prior to powering off.

Page 39

3.21 Top & Bottom End Caps

The top & bottom end panels are where all connections are made to the CMX The diagram above shows the layout and description of the connectors:

Transducer Connectors

DL+

Refer to Diagram: The transducer connectors, and battery cover/probe zero disk are located on the CMX

DL+

’s top end cap. The transducer connectors are of type Lemo

“00”. Note: There is no polarity associated with connecting the transducer to the

DL+

CMX

Probe Zero Disk & Battery Cover Refer to Diagram: The Battery cover is the large round disk shown in the diagram.

Note: This same disk is also used as a probe zero disk. Simply remove the cover

when replacing the batteries (3 AA cells). When performing a manual probe zero function, simply place the transducer on disk making firm contact. Important: Be sure to follow the polarity labels located on the back label of the CMX

DL+

. Note:

Rechargeable batteries can be used, however they must be recharged outside of the unit in a stand alone battery charger.

RS-232 Connector Refer to Diagram: The RS-232 connector, located on the bottom end cap, is a 2 pin

female Lemo connector. It is designed to connect directly from the CMX standard AT serial port on a PC. The cable supplied with the CMX

pin serial cable. Note: This connector is also used to upgrade the CMX

DL+

to a

is a Lemo to 9

DL+

with the

latest version of firmware.

USB Serial to USB Converter Cable

A converter cable can be attached to the 9 pin serial cable in needed (part no. N -402-

0510).

Page 40

CHAPTER FOUR PRINCIPALS OF ULTRASONIC MEASUREMENT

4.1 Time versus thickness relationship

Ultrasonic thickness measurements depend on measuring the length of time it takes for sound to travel through the material being tested. The ratio of the thickness versus the time is known as the sound velocity. In order to make accurate measurements, a sound velocity must be determined and entered into the instrument.

The accuracy of a thickness measurement therefore depends on having a consistent sound velocity. Some materials are not as consistent as others and accuracy will be marginal. For example, some cast materials are very granular and porous and as a result have inconsistent sound velocities.

While there are many different ultrasonic techniques to measure thickness, which will be discussed below, all of them rely on using the sound velocity to convert from time to thickness.

4.2 Suitability of materials

Ultrasonic thickness measurements rely on passing a sound wave through the material being measured. Not all materials are good at transmitting sound. Ultrasonic thickness measurement is practical in a wide variety of materials including metals, plastics, and glass. Materials that are difficult include some cast materials, concrete, wood, fiberglass, and some rubber.

4.3 Range of measurement and accuracy

The overall measurement capabilities, based on the wide variety of materials, is determined by the consistency of the material being measured

The range of thickness that can be measured ultrasonically depends on the material as well as the technique being used and the type of transducer. Thickness measurements can be made from a minimum of 0.010 inch to 9.999” in steel. However, the maximum attainable thickness is much less for more attenuative materials (materials that absorb sound).

Accuracy, is determined by how consistent the sound velocity is through the sound path being measured, and is a function of the overall thickness of the material. For example, the velocity in steel is typically within 0.5% while the velocity in cast iron can vary by 4%.

4.4 Couplant

All ultrasonic applications require some medium to couple the sound from the transducer to the test piece. Typically a high viscosity liquid is used as the medium. The sound frequencies used in ultrasonic thickness measurement do not travel

Page 41

DL+

CMX

High Performance Material & Coating Thickness Gauge

through air efficiently. By using a liquid couplant between the transducer and test piece the amount of ultrasound entering the test piece is much greater.

4.5 Temperature

Temperature has an effect on sound velocity. The higher the temperature, the slower sound travels in a material. High temperatures can also damage transducers and present a problem for various liquid couplants.

Since the sound velocity varies with temperature it is important to calibrate at the same temperature as the material being measured.

Normal temperature range

Most standard transducers will operate from 0°F to 180°F.

High temperature measurements

Special transducers and couplants are available for temperatures above 180°F up to 650°F with intermittent contact. It is necessary to cool the transducer, by submerging the transducer in water between readings, when measuring high temperatures.

Modes and temperature errors

In addition to errors caused by velocity changing with temperature, some modes (measurement techniques) are affected more than others. For example, dual element pulse-echo mode has larger errors due to changes in the temperature of the delay line. However, multi-echo techniques offer temperature compensation help to minimize these errors.

4.6 Measurement Modes

In this section we will discuss the different measurements modes the CMX capable of operating in, the transducers required, and the reasons for using specific modes:

Pulse-Echo Mode (Flaw & Pit detection) – Coating Off (P-E)

Pulse-echo mode measures from the initial pulse (sometimes referred to as an artificial zero) to the first echo (reflection). In this mode, either an automatic or manual zero can be performed depending on the zero probe function setting. If the manual mode has been selected, the transducer is placed on a reference disk, located on top of the CMX

DL+

, and a key is pressed to establish a zero point for the particular transducer. If the Auto Zero feature is enabled, a simple key press will perform an electronic zero to establish the same zero point.

In this mode errors result from surface coatings and temperature variations.

DL+

Since pulse-echo only requires one reflection, it is the most sensitive mode for measuring weak reflections (flaws) typically found when measuring he avily corroded metals.

Page 42

Dakota Ultrasonics

V-Path Correction

Dual element delay line transducers have two piezoelectric elements mounted at an angle on one end of the delay line. One element is used for transmitting sound, while the other element only receives sound. The tw o elements and their delay lines are packaged in a single housing but acoustically isolated from each other with a sound barrier. This allows the transducer the ability to achieve very high sensitivity for detecting small defects. Also, the surface of th e test material does not have to be as flat in order to obtain good measurements.

Dual element transducers are normally used in pulse-echo mode for finding defects, and in echo-echo mode for through coating measurements.

Dual element delay line transducers are usable over a range of 0.025 inches to 20 inches depending on the material, frequency, and diameter.

A limitation of dual element delay-line transducers is the V shaped sound path. Because the sound travels from one element to another, the time versus thickness relationship is non-linear. Therefore, a correction table in the instruments software is used to compensate for this error.

Dual Element Transducer showing V-path of signal

Searching for small defects

Dual element delay line transducers are especially useful in searching for small defects. In the pulse-echo mode with high amplifier gain, very small defects can be measured. This is very useful during corrosion inspections overall. The dual element style transducer will find wall deteriorati on, pits, and any porosity pockets during tank and pipeline inspections.

Echo-Echo Mode – Thru Coat (E-E)

The echo-echo mode measures between two reflections. This technique is commonly used to eliminate errors from surface coatings and also to make measurements in multiple layered materials. The disadvantage is that two echoes are needed which requires a much stronger echo (reflection).

Page 43

DL+

CMX

High Performance Material & Coating Thickness Gauge

Dual Element Transducer in Echo to Echo mode

Echo-Echo Verify Mode – Thru-Verify (E-EV)

The echo-echo verify mode measures between 3 reflections. Similar to E-E mode, this technique is commonly used to eliminate errors from surface coatings and also to make measurements in multiple layered materials. The primary benefit of this mode, is that a comparison is made, between the 2nd and 3rd echoes, to verify that a peak jump has not occurred, providing an additional level of confidence to the measurement. The disadvantage is that 3 reflections are needed which requires the use of gates with controllable thresholds to adjust for sensitivity over a given measurement range.

Dual Element Transducer in Echo to Echo mode

Pulse Echo Coating Mode – Coating On (PECT)

A custom hybrid combination mode using properties from the basic modes along with a group of special techniques and theoretical wave phenomena’s to measure coating and material thicknesses at the same time, while still retaining the ability to locate flaws and pits in materials. Therefore, the best description for this hybrid mode is Pulse-Echo Coating mode.

Coating Mode – Coating Only (CT)

Once again, this is a custom hybrid combination mode using special techniques to effectively measure the thickness of coatings that are either adhered to metallic surfaces or in stand alone form . In this mode a two point calibration must be performed. If the user will be measuring coating that has been applied to a metal surface, the calibration must be performed using coating samples coupled to a metal surface when calibrating. To explain further, a drop of couplant must be applied in between the coating samples and metal surface. If the coating has not been applied to a metal surface, the calibration should be performed accordingly.

Page 44

Dakota Ultrasonics

Pulse-Echo Temperature Compensated Mode – Temp Comp (PETP)

This is a custom mode that combines pulse-echo and electronic zero techniques to automatically adjust for temperature changes in the transducer as a result of an increasing/decreasing temperature gradient in the test material. Note: rough surface conditions can have an effect on the overall accuracy in this mode. If the surface condition is in question, the pulse-echo mode should be used in conjunction with performing an off block automatic zero as the temperature gradient changes.

Page 45

CHAPTER FIVE SELECTING THE MEASUREMENT MODE

5.1 The setup library

The CMX for easy recall. These setups can be optimized for the user’s specific application needs and can also be stored on a PC and transferred bi-directionally using Dakota’s PC interface software included with the instrument.

The setups supplied with the instrument cover some of the more typical applications commonly used with this type of instrument. These setups can be recalled, modified, and overwritten to one of 64 setup locations. Therefore, these factory setups can also be considered a good starting point to be modified for custom applications. The PC software includes a default setup file that can be uploaded to the gauge at any time to restore factory settings. However, it is recommended that the user consider saving modified setups to an empty location rather than overwriting the factory setups in the CMX custom setups.

DL+

contains 64 user configurable preset locations to store custom setups

DL+

. Once again, these factory settings are excellent starting points for

5.2 Which mode & transducer do I use for my application?

High penetration plastics and castings

The most common mode for these types of applications is pulse-echo. The CMX

DL+

has been optimized for cast materials. Cast iron applications require 1 - 5MHz frequencies, and cast aluminum requir es a 10MHz frequency. Plastics typically require lower frequencies depending on the thickness and make-up of the material. Larger diameters offer greater penetration power because of the crystal size, for difficult to measure materials.

Corrosion & Pit Detection in steel and cast materials

Use pulse-echo mode whenever attempting to locate pits and flaws. Typically a 5MHz transducer, or higher, will be used for these types of applications. Use low frequencies for greater penetration and use higher frequencies for better resolution.

Measuring Material & Coatings

The pulse-echo coating mode should be used when both material and coating thickness are required, while still requiring the ability to detect flaws and pits. A special coating style transducer is required for use in this mode. There are a variety of coating transducers in various frequencies available from Dakota.

Page 46

Dakota Ultrasonics

Thru Paint & Coatings

Often times, users will be faced with applications where the material will be coated with paint or some other type of epoxy material. Since the velocity of the coating is approximately 2.5 times slower than that of steel, pulse-echo mode will induce error if the coating or paint is not completely removed. By using echo-echo mode, the user is able to successfully measure through both, the coating and steel, and completely eliminate the thickness of the paint or coating. Therefore, the steel can be measured without having to remove the coating prior to measuring. Users will often use pulseecho mode and echo-echo mode in conjunction when performing inspections on coated materials.

Thru coating measurements require special high damped transducers. The most common transducers are the 3.5, 5, and 7.5MHz hi damped transducers. These transducers are suitable for use in both pulse-echo and echo-echo modes. This conveniently enables the user to accurately measure overall material thickness using the thru Coating mode, and then conveniently switch to pit detection mode without changing transducers. The ¼” 5MHz Hi damped transducer is the most commonly used transducer for standard thru coating applications.

Coating Only The coating only mode should be used when the application calls for coating

measurements only and the user is not interested in the thickness of the material the coating has been applied to. This mode can also be used as a stand alone coating thickness gauge, where the coating has not been applied to another material surface. An auto identified coating probe must be attached to the CMX

DL+

in order to enable

this mode.

Thin materials

Use pulse echo mode and a high frequency transducer for these types of applications. The most common transducers are the 7.5MHz and 10MHz models with extra resolution. The higher frequencies provide greater resolution and a l ower minimum thickness rating overall.

High temperature

Use and select a special 2.25MHz and 5 MHz High temperature transducer for these types of applications. Both pulse-echo and echo-echo modes will also work for these applications. However, echo-echo mode will eliminate error caused by temperature variations in the delay line of the transducer.

Noisy Material

Materials such as titanium, stainless steel, and aluminum may have inherent surface noise issues. This is a signal that appears at the surface of the material when using a dual element delay line probe. Select a higher frequency transducer to reduce this noise – 7.5MHz and higher for better resolution.

Page 47

DL+

CMX

High Performance Material & Coating Thickness Gauge

Restricted access

Measuring materials with extreme curvatures or restricted access, higher frequencies with smaller diameters should be considered. The smallest diameter uses 3/16” crystals with a contact area of .250”. Custom transducers are available on request.

5.3 Factory Setup Chart

Num Name Comment 1 Gn/AGC Velocity

1 Enter Custom Name 2 … 3 … 4 … 5 … 6 … … …

Page 48

CHAPTER SIX MAKING MEASUREMENTS

The steps involved in making measurements are detailed in this section. The following sections outline how to setup and prepare your CMX

DL+

for field use.

An automatic or manual zero must always be performed. The auto zero is an off block electronic zero that does not require a zero reference block. This will most always be the zero option of choice, as it makes the zeroing process very easy and convenient to perform. However, If the manual zero option is enabled, the probe zero must be measured on the reference disk (battery disk) attached to the top of the instrument. The zero compensates for variations in the transducer. In all modes the sound velocity must be determined. The sound velocity is used to convert the transit time to a physical length. The sound velocity can be selected from a material chart in the manual, selected from a material list in the CMX

DL+

, or for greater precision determined from a sample of the test material that has been mechanically measured. To enter the velocity from a table, look up the material on the chart in the appendix of this manual and refer to the section below on Calibration to a Known Velocity. To determine the velocity of a single sample, refer to the Material Calibration section on page 54.

When measuring curved materials, it is more accurate to calibrate from two test points, one at the minimum limit of the target thickness and one at the maximum limit. In this case the reference disk mounted to the CMX

DL+

is not used. This is called

two-point calibration and is described on page 56.

6.1 Auto Probe Recognition & Selecting The Transducer Type

The first step in using the CMX the unit up. The CMX

DL+

has a special built -in automatic probe recognition feature that will check to see if the probe plugged into the gauge is an auto recognized probe type. If so, the CMX

DL+

will display a message indicating the transducer type and ask the user for confirmation to use the identified probe. If the transducer is not an auto recognized probe, the CMX has not been recognized, and force the user to select a transducer type from a list of transducers according to frequency and diameter. Whether the transducer is auto recognized or selected from a predefined list, the CMX properties about the transducer. Note: Once the transducer has been selected, the

DL+

CMX

will store and recall this transducer type every time the CMX on/off. The type will only change if the user physically selects another type from the list, or selects a previously saved setup. Therefore, if you have previously gone through this section and selected the transducer you are using, proceed to the next section. Use the following steps to select your transducer type. Note: If the

transducer is not identified on power up, be sure the transducer type selected is the same as the transducer plugged into the CMX

erroneous measurements:

DL+

is to plug the transducer into the gauge and power

DL+

will display a message indicating the transducer type

DL+

will recall specific

DL+

is powered

DL+

. Failure to do this will result in

Page 49

DL+

CMX

High Performance Material & Coating Thickness Gauge

In this first example the transducer was automatically identified:

Probe Aut omatically Recognized

1) Press the OK key once to use the identified probe, or ESC to display a list of

optional transducers. Note: if the CMX

DL+

recognizes a specific

CMX

2) Assuming the CMX the CMX

DL+

has somehow identified the probe in error. .

DL+

recognized the probe and the OK key was pressed,

DL+

will advance to a Zero Probe menu. If the transducer was

identified as a special transducer capable of measuring coating thickness, a menu will be displayed allowing the user the ability to toggle the coating thickness display on/off as follows:

Page 50

Dakota Ultrasonics

3) Press the UP and DOWN arrow keys to toggle the coating option on/off.

4) Wipe all couplant from the transducer face and proceed to the Probe Zero section that follows.

In this second example the transducer was not identified and will force the user to select the transducer type fr om a predefined list of transducers:

Selecting the Transducer Type

5) Press the OK or ESC keys to display the factory list of transducer types (by diameter and frequency).

Page 51

DL+

CMX

High Performance Material & Coating Thickness Gauge

6) Press the UP and DOWN arrow keys to scroll through the transducer list until the appropriate type is highlighted.

7) Press the ENTER key to select the transducer type and display overwrite existing probe screen.

8) Press the OK key to overwrite the existing probe type with the newly selected probe type. The zero probe screen will be displayed. Proceed to the zero probe section that follows.

Page 52

Dakota Ultrasonics

6.2 Probe zero

The next step is to perform a probe zero. The zero function is a very important and necessary function that must be done prior to calibration. It should be done on a regular basis. In fact, the CMX regular intervals during operation if it hasn’t been done. If the CMX correctly, all the measurements taken may be in error by some fixed value. When the CMX

DL+

is using the auto zero (electronic zero), the CMX measurement mode. However, when the manual zero is being used, the CMX must be in pulse-echo mode in order to perform the zero. The CMX to it that this occurs by simply forcing the gauge into this mode when zero. Therefore, if the CMX

DL+

is in the echo-echo measurement mode and a manual zero is being performed, the CMX automatically before performing the zero. While this is a very convenient feature of the CMX

DL+

, the user should be sure to check the measurement mode following calibration to be sure the CMX both of these techniques.

The CMX

DL+

is equipped with two zero options:

1) Off Block Zero (Automatic Probe Zero) – When this feature is enabled the

DL+

CMX

will do an electronic zero automatically, eliminating the need for a zero

disk or block.

2) On Block Zero (Manual Probe Zero) – When this feature is enabled the transducer must be placed on the probe zero disk (battery cover located on the top of the unit.

Both zero procedures are outlined as follows:

DL+

has been programmed to force this issue at

DL+

will put the gauge into pulse-echo mode

DL+

is in the desired mode. The following steps outline

DL+

is not zeroed

can be in any

DL+

will also see

DL+

Performing an Auto Probe Zero (Off Block)

Coating Probe Identified Coating Probe Not Identified

Page 53

DL+

CMX

High Performance Material & Coating Thickness Gauge

1) Be sure all couplant has been removed from the face of the transducer.

2) Press the OK key to perform the automatic probe zero, or ESC key to cancel the zero operation.

Coating Probe Identified Coating Probe Not Identified

3) The screens illustrated above will be briefly displayed followed by the main measurement screen. The CMX

DL+

is ready to be calibrated.

Page 54

Dakota Ultrasonics

Performing a Manual Probe Zero (On Block)

Note: When the zero probe option is set to manual, the probe zero disk

(battery cap) located on the top of the gauge will be used as a zero standard and the warning screen illustrated above will be displayed.

1) Press the OK or ESC keys to enter the main measurement screen and begin the manual zero process.

2) Apply a drop of couplant on the transducer and place the transducer in steady contact with the probe zero disk and obtain a steady reading.

4) Press the UP and DOWN arrow keys to scroll through the sub menu items until ZERO PROBE is highlighted.

Page 55

DL+

CMX

High Performance Material & Coating Thickness Gauge

Coating Probe Identified Coating Probe Not Identified

5) Press the ENTER key to display the confirmation screen.

6) If a coating transducer was identified use the UP and DOWN arrow keys to toggle coating on/off.

7) Press the OK key to complete the probe zero function, or ESC key to cancel the probe zero fun ction.

8) Remove the transducer from the probe zero disk, and proceed to the calibration section.

Note: The value that is displayed will change depending on the current velocity setting in the CMX. Disregard the number that is displayed. It is not important. What is important is accurately performing the steps outlined above to insure reliability of the probe zero calculation.

6.3 Material Calibration

In order for the CMX sound velocity of the material being measured. Different types of materials have different inherent sound velocities. For example, the velocity of sound through steel is about 0.233 inches per microsecond, versus that of aluminum, which is about

0.248 inches per microsecond. If the gauge is not set to the correct sound velocity,

DL+

to make accurate measurements, it must be set to the correct

Page 56

Dakota Ultrasonics

all of the measurements the gauge makes will be erroneous by some fixed percentage.

The One Point calibration is the simplest and most commonly used calibration method - optimizing linearity over large ranges. The Two Point calibration allows for

greater accuracy over small ranges by calculating the probe zero and velocity. The

DL+

CMX

provides four simple methods for setting the sound-velocity outlined below:

Known Velocity

If the material velocity is known, the user may wish to simply enter the velocity number into the CMX

DL+

, rather than have the CMX

DL+

calculate the velocity value using a known thickness on a material sample. The steps for entering the velocity are outlined below:

Using a Known Material Velocity

2) Use the UP and DOWN arrow keys to scroll through the sub menu items until VELOCITY is highlighted.

Page 57

DL+

CMX

High Performance Material & Coating Thickness Gauge

3) Press the ENTER key to display the Digits Edit Box.

4) Press the UP and DOWN arrow keys to scroll the highlighted value.

5) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

6) Repeat steps 4 & 5 until the velocity number is correctly displayed.

7) Press the OK key to set the velocity and return to the menu screen, or ESC to cancel entering the velocity.

8) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Page 58

Dakota Ultrasonics

Known Thickness

Sometimes the sound velocity of a material is unknown. In this case a sample with one or two known thicknesses can be used to determine the sound velocity. As previously discussed, the CMX

DL+

has a one or two point calibration option. The one point calibration option is most suited for linearity over large ranges, as noted above. The user should also consider calibrating on high side of the intended measurement range, when using the one point option, minimize over all error. For example, if the measurement range is .100” (2.54mm) to 1.0” (25.4mm), the user should calibrate on a known thickness sample close to 1.0” (25.4mm). Note: It’s always handy to carry a set of mechanical calipers to use in conjunction with the CMX

DL+

for calibration in the

field:

One Point Calibration

Note: Be sure that the probe zero procedure has been performed prior to

performing this calibration procedure.

1) Physically measure an exact sample of the material or a location directly on the material to be measured using a set of calipers or a digital micrometer.

2) Apply a drop of couplant on the transducer and place the transducer in steady contact with the sample or actual test material. Be sure that the reading is stable and the repeatabil ity indicator, in the top left corner of the display, is fully lit and stable. Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the

Page 59

DL+

CMX

High Performance Material & Coating Thickness Gauge

ESC key multiple times to tab left until the CAL menu is highlighted and displaying the submenu items.

3) Use the UP and DOWN arrow keys to scroll through the sub menu items until MATL 1PT is highlighted.

4) Press the ENTER key to display the Digits Edit Box.

5) Press the UP and DOWN arrow keys to scroll the highlighted value.

6) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

7) Repeat steps 5 & 6 until the known thickness value is correctly displayed.

8) Press the OK key to calculate the velocity and return to the menu screen, or ESC to cancel the one point calibrat ion.

9) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Note: CHECK YOUR CALIBRATION! Place the transducer back on the calibration point. The thickness reading should now match the known thickness. If the thickne ss is not correct, repeat the steps above.

At some point there may become a requirement for improved accuracy over a smaller measurement range. In this case, a two point calibration would be most suited for

Page 60

Dakota Ultrasonics

the job. For example, if the measurement range was .080” (2.03mm) to .250” (6.35mm), the user would perform a one point calibration on a known thickness sample close to .250” (6.35mm), followed by a two point calibration close to .080” (2.03mm). When a two point calibration is performed, the CMX

DL+

calculates the

zero and the velocity. The following steps outline this procedure:

Two Point Calibration

1) Physically measure an exact sample of the material or a location directly on the material to be measured using a set of calipers or a digital micromet er.

display, is fully lit and stable. Press the MENU key once to activate the menu items tab. Press the MENU key multiple times to tab right and the ESC key multiple times to tab left until the CAL menu is highlighted and displaying the submenu items.

3) Use the UP and DOWN arrow keys to scroll through the sub menu items until MATL 2PT is highlighted.

Page 61

DL+

CMX

4) Press the ENTER key to display the Digits Edit Box.

5) Press the UP and DOWN arrow keys to scroll the highlighted value.

High Performance Material & Coating Thickness Gauge

6) Press the LEFT and RIGHT arrow keys to scroll the digit locations.

7) Repeat steps 5 & 6 until the known thickness value is correctly displayed.

8) Press the OK key to calculate the velocity and return to the menu screen, or ESC to cancel the one point calibration.

9) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

Note: CHECK YOUR CALIBRATION! Place the transducer back on the calibration point. The thickness reading should now match the known

thickness. If the thickness is not correct, repeat the steps above.

Basic Material Type

If the material velocity is unknown, and a sample thickness cannot be taken from the material, the user may opt to choose a basic material type from a list with approximate velocity values according to various material types. It’s important to note that these velocities will not always be an exact representation of the material

Page 62

Dakota Ultrasonics

being tested. Use these values only if a close approximation is acceptable. Follow the steps below to select a basic material type:

Selecting a Basic Material Type

2) Use the UP and DOWN arrow keys to scroll through the sub men u items until MAT is highlighted.

3) Press the ENTER key to display the list of material types.

Page 63

DL+

CMX

High Performance Material & Coating Thickness Gauge

4) Press the UP and DOWN arrow keys to scroll through the material list until the appropriate material is highlighted.

5) Press the ENTER key to overwrite the material type and display the menu items with the new material type selected.

6) Finally, press the MEAS key to return to the measurement screen and begin taking readings.

To calibrate the CMX

DL+

for a specific type of coating using samples with known

thicknesses, please refer to the chapter 9 – Pulse-Echo Coating (PECT) or

Coating (CT) for a complete explanation of using the CMX

DL+

for coating

measurements.

Page 64

CHAPTER SEVEN USING THE DISPLAY OPTIONS

A key feature of the CMX

DL+

is the ability to toggle between four different display options; Digits, RF, RECT and B-Scan. All views provide a digital readout of base material and coating thickness measurements, while also displaying the alarm tolerances, if active. A key feature of the CMX

DL+

is the waveform display. The waveform is a graphical representation of the sound reflections returning to the transducer. Consider standing at the base of a canyon and screaming “Hello There”. After a brief delay, you will here multiple echoes, “Hello There’s” repeated back to you. The waveform display shows the amplitude of the signal received on the vertical (Y) axis and time (shown in units of thickness) on the horizontal (X) axis. The waveform display is very useful for viewing and adjusting the location of the gates. The gates are typically used to eliminate potential surface noise by adjusting the starting point in single echo modes, for multi echo measurement modes, as well as to adjust the threshold (sensitivity) in either mode. The waveform display is also very useful for locating pits and internal flaws in materials.

The B-Scan display is also very useful when scanning surfaces and viewing the cross section of the test material. It provides a convenient way of visually profiling, or drawing a picture of, the blind surfaces during a scan. The B-Scan display is also equipped with a scan bar representing the overall thickness. The scan bar gives the user a visual indication when a flaw or defect passed over during the scan process. The scan bar will deflect off of the defect and return back to the overall thickness. Visually, this is much easier to notice than watching for changes in the digital value displayed. The scan bar has also been included in the large digits display mode for the same purpose.

Note: The following chapter outlines some of the fine adjustment features of the

CMX

DL+

. The CMX

DL+

has four different display options (RF A-Scan, Rectified A-

Scan, B-Scan, and Large Digits). We’ll take a better look at these options in this

chapter. Note: In order to recall and use the new adjustments made to the CMX

DL+

at a later time, the user must save the modified settings in one of the setup locations prior to powering off the unit. Refer page 157 for more information on setups.

Page 65

CMX

7.1 Display Views

DL+

High Performance Material & Coating Thickness Gauge

DIGITS VIEW

DIGITS

The Digits view is a basic digital thickness gauge look and feel. The larger digits make it much easier for the operator to monitor the thickness readings. The Scan Bar has also been added to the Digits view to provide the user with yet another visual tool for easily monitoring changes in thickness readings due to internal flaws or defects.

The following is a list of the viewable features on the display:

A. Repeatability/Stability Indicator – This indicator should be commonly used

in conjunction with the digital thickness values displayed. When all the vertical bars are fully illuminated and the last digit on the digital thickness value is stable, the CMX

DL+

is reliably measuring the same value 3 to 200 times per

second, depending on which measurement mode and features are enabled. B. Battery Icon – Indicates the amount of battery life the CMX C. Velocity – The material velocity value the CMX

DL+

is currently using or

DL+

has remaining.

calibrated for. Displayed in English or Metric units, depending on the what

units the gauge is set for. D. Feature Status Bar – Indicates the features currently enabled and in use in

the following order:

• Measurement Mode (P-E, PECT, PETP, E-E, E-EV, COAT)

• Differential Mode (ON/OFF)

• High Speed Scan Mode (ON/O FF)

Page 66

Dakota Ultrasonics

• Alarm Mode (ON/OFF/AUDIBLE)

• Gain Setting (VLOW, LOW, MED, HI, VHI)

E. Digital Material Thickness Value – Extra large font size for viewing ease. F. Scan Bar – Another view of material thickness in a deflection style horizontal

bar. This is another visual tool that would enable the user the ability to see

thickness changes during high speed scans from flaws and pits. G. Units – The current measurement units being used (English, Metric). H. Coating Thickness Value – Displays the actual thickness of any coating

adhered to a metallic material surface (PECT Mode), or a coating adhered to a

non-metallic surface (CT Mode). I. Minimum Material Thickness – Part of the Alarm feature. Displays the

minimum thickness value found during a scan. J. Maximum Material Thickness – Part of the Alarm feature. Displays the

maximum thickness value found during a scan.

B-Scan View

B-Scan

The B-Scan displays a time based cross section view of test material. This view is commonly used to display the contour of the blind, or underside, surface of a pipe or tank application. It is very similar to a fish finder. If a flaw or pit is located during a scan, the B-Scan will draw the pit on the screen. The solid black rectangle in the diagram at location K represents the cross section, or side view of the material. The B-Scan view draws at a rate of 7 seconds per screen from right to left. Also notice at location K, the pits and corroded bottom surface of the material.

It’s important to note that the measurement range on the display be set wide enough, so that the maximum thickness of the material can be viewed on the display. Using the diagram above, if the material thickness was actually 1.75”, the underside of the material would not be viewable according to the current range at 0.00” – 1.00”. All

Page 67

DL+

CMX

High Performance Material & Coating Thickness Gauge

the user would see is a black screen from 0.00” – 1.00” with no view of the bottom contour at 1.75”.

The following is a list of the viewable features on the display:

A. Repeatability/Stability Indicator – This indicator should be commonly used

in conjunction with the digital thickness values displayed. When all the vertical bars are fully illuminated and the last digit on the digital thickness value is stable, the CMXDL is reliably measuring the same value 3 to 200 times per

second, depending on which measurement mode and features are enabled. B. Battery Icon – Indicates the amount of battery life the CMXDL has remaining. C. Velocity – The material velocity value the CMXDL is currently using or

calibrated for. Displayed in either English or Metric units, depending on the

what units the gauge is set for. D. Feature Status Bar – Indicates the features currently enabled and in use in

the following order:

• Measurement Mode (P-E, PECT, PETP, E-E, COAT)

• Differential Mode (ON/OFF)

• High Speed Scan Mode (ON/OFF)

• Alarm Mode (ON/OFF/AUDIBLE)

• Gain Setting (VLOW, LOW, MED, HI, VHI)

E. Digital Material Thickness Value – Smaller font size when the B-Scan

display view is enabled. F. Scan Bar – Another view of material thickness in a deflection style horizontal

bar. This is another visual tool that would enable the user the ability to see

adhered to a metallic material surface (PECT Mode), or a coating adhered to a

non-metallic surface (CT Mode). I. Minimum Material Thickness – Part of the Alarm feature. Displays the

minimum thickness value found during a scan. J. Maximum Material Thickness – Part of the Scan feature. Displays the

maximum thickness value found during a scan. K. B-Scan Display – Cross section view of the material. Provides the user with

graphical view of the opposite/blind surface (i.e. inside pipe wall surface), to

give the user some idea of the condition, or integrity of the material being

tested.

Page 68

Dakota Ultrasonics

RF A-Scan View

Radio Frequency (RF) A-Scan

The RF mode shows the waveform in a similar fashion to an oscilloscope. It shows both the positive and the negative peaks. The peak (either positive or negative) selected for measurement is shown in upper portion of the display.

It’s important to note that a measurement must fall inside the displays viewable range in order to see the waveform. However, even if the waveform is outside of th e viewable range of the display, a measurement can be taken and viewed on the digital readout. If the wave is outside of the display range, you can manually change the range by adjusting the Delay and Width values, or you can use the Auto Find feature located in the UTIL menu of the tabbed menu items. Refer to page 109 for additional information on the Auto Find feature.

The following is a list of the viewable features on the display:

A. Repeatability/Stability Indicator – This indicator should be commonly used

in conjunction with the digital thickness values displayed. When all the vertical bars are fully illuminated and the last digit on the digital thickness value is stable, the CMX

DL+

is reliably measuring the same value 3 to 200 times per

second, depending on which measurement mode and features are enabled.

B. Battery Icon – Indicates the amount of battery life the CMX

DL+

has remaining.

C. Detect Indicator – The broken vertical line displays the zero crossing (flank)

detection point on the waveform where the measurement has been obtained. Notice that the digital thickness readout is the same as the location of the detect indicator according to the measurements labels F, also in the diagram.

D. Baseline - The horizontal trace across th e A-scan presentation for a no signal

condition. It represents time and is generally related to material distance or thickness.

Page 69

DL+

CMX

High Performance Material & Coating Thickness Gauge

E. Gate – An electronic feature that allows the user to monitor signals inside the

boundaries of the gate settings. The height of the gate from the baseline is

known as the threshold, and controls the sensitivity of the reflections that

trigger a detection from the opposite surface of the material. F. Measurement Scale – Represents thickness values over a defined

measurement range, and labeled at the calibrated hash marks on the display

(X) axis. G. Digital Material Thickness Value – The thickness of the base material. H. Minimum Thickness Value – Dynamically updates the value during a scan,

and displays the minimum thickness value found. Note: Only visible when

high speed scan mode is enabled. I. Units – The current measurement units being used (English, Metric).

J. Velocity – The material velocity value the CMXDL is currently using or

calibrated for. Displayed in either English or Metric units, depending on what

units the gauge is set for. K. RF waveform – The sine wave created by the reflected sound, or oscillation,

from the material being measured. The both the positive and negative half

cycles (full cycles) are displayed. L. Coating Thickness Value – Displays the actual thickness of any coating

adhered to a metallic material surface (PECT Mode), or a coating adhered to a

non-metallic surface (CT Mode). M. Minimum Thickness Value – Dynamically updates the value during a scan,

and displays the minimum th ickness value found. Note: Only visible when

high speed scan mode is enabled. N. Feature Status Bar - Indicates the features currently enabled and in use in

the following order:

• Measurement Mode (P-E, PECT, PETP, E-E, COAT)

• Differential Mode (ON/OFF)

• High Speed Scan Mode (ON/OFF)

• Alarm Mode (ON/OFF/AUDIBLE)

• Gain Setting (VLOW, LOW, MED, HI, VHI)

Page 70

Dakota Ultrasonics

RECT A-Scan View

Rectified (RECT) A-Scan

It’s important to note that a measurement must fall inside the displays viewable range in order to see the waveform. However, even if the waveform is outside of the viewable range of the display, a measurement can be taken and viewed on the digital readout. If the wave is outside of the display range, you can manually change the range by adjusting the Delay and Width values, or you can use the Auto Find feature located in the UTIL menu of the tabbed menu items. Refer to page 109 for additional information on the Auto Find feature.

The following is a list of the viewable features on the display:

A. Repeatability/Stability Indicator – This indicator should be commonly used

in conjunction with the digital thickness values displayed. When all the vertical bars are fully illuminated and the last digit on the digital thickness value is stable, the CMX

DL+

is reliably measuring the same value 3 to 200 times per

second, depending on which measurement mode and features are enabled.

B. Battery Icon – Indicates the amount of battery life the CMX

DL+

has remaining.

C. Detect Indicator – The broken vertical line displays the zero crossing (flank)

D. Baseline - The horizontal trace across the A-scan presentation for a no signal

condition. It represents time and is generally related to material distance or thickness.

Page 71