NDT Systems Curlin-Air User manual

Brand: NDT Systems

Model: Curlin-Air

Type: User manual

SAFETY PRECAUTIONS ............................................ 4

1. INTRODUCTION ................................................ 2

Basic System Components ...................................... 2

2.0 Specifications.................................................. 3

3.0 Operator Qualifications ........................................... 5

3.1 Operational Notations .................................... 5

KEYS ................................................. 5

VARIABLES............................................ 5

SCROLLING ........................................... 5

TOGGLING ............................................ 5

CURSOR .............................................. 5

4.0 Transducers and Reference Standards .............................. 6

5.0 MENU DESCRIPTIONS.......................................... 7

5.1 Special Menu & Keyboard ................................... 7

Help Screens ........................................... 7

Menu Flow ............................................. 7

5.2 MENUS ................................................. 8

5.2.1 MAIN MENU ...................................... 8

ENERGY......................................... 8

BLANK .......................................... 8

Example .................................... 8

BLNKADJ ........................................ 9

GAIN ............................................ 9

RANGE .......................................... 9

DELAY .......................................... 9

GATE ........................................... 9

AMPLITUDE................................. 9

DISTANCE .................................. 9

IF IN AMPLITUDE MODE............................ 9

ALARM POLARITY ........................... 9

START ..................................... 9

WIDTH .................................... 10

LEVEL .................................... 10

IF IN DISTance MODE ............................. 10

VELOCITY ................................. 10

ZERO ADJUST.............................. 10

BLOCK.................................... 10

LEVEL .................................... 10

AUDIO.......................................... 10

5.2.2 DISPLAY MENU ................................. 10

DISP ........................................... 10

HOLLOW .................................. 10

SOLID .................................... 10

SMOOTH ....................................... 10

GRID .......................................... 10

FREEZE................................... 11

BACK LIGHT .................................... 11

CONTRAST ..................................... 11

BEEP .......................................... 11

LOCK .......................................... 11

5.2.3 MISC Menu...................................... 11

BATTERY TEST.................................. 11

MODE.......................................... 11

UNITS.......................................... 11

SAVE SETUP .................................... 12

Rcall ........................................... 12

PRINT.......................................... 12

AlmTim ......................................... 12

PRF ........................................... 13

6.0 Curlin AIR SETUP AND OPERATING CONSIDERATIONS ............. 14

6.1 Safe Operation ........................................ 14

6.2 Safe Inspection Site .................................... 14

6.3 Ambient Ultrasonic Noise ................................ 14

6.4 Calibrate Before Performing Any Inspection !! ................ 14

6.5 Reference Samples..................................... 14

6.6 Operational Considerations ............................... 14

6.7 Curlin AIR Display Characteristics.......................... 15

6.8 Factory Setup Variables ................................. 15

7.0 Flaw Detection Procedures .................................... 16

7.1 Mechanical Assembly ................................... 16

7.1.2 Adjustment of Yoke ............................... 16

7.1.3 Cable Attachment to Curlin-AIR ...................... 16

7.2 Electronic Initialization & Checkout ......................... 16

7.2.1 Power-ON....................................... 16

7.2.2 Message Display ................................. 16

7.2.3 Automatic Initializing Set-up ......................... 16

7.2.4 Insert Material Into Beam ........................... 16

7.3 CALIBRATION ........................................ 17

7.3.1 “Calibration” On Reference Samples .................. 17

7.3.2 Reference Sample ................................ 17

7.3.3 Curlin-AIR Adjustment On Reference Sample ........... 17

7.3.4 Maximum Scan Speed Determination ................. 17

7.3.5 Edge Effects ..................................... 17

7.4 Keep Equipment Clean .................................. 18

7.5 TECHNICAL ASSISTANCE ............................... 18

8.0 Output and Optional Printer Technical Specifications ................. 19

8.1 RS-232C Output Specifications ............................ 19

8.2 Printers .............................................. 19

9.0 Battery Pack and Charger ....................................... 20

10 Optional Curlin AIR Accessories ................................. 21

11 WARRANTY .................................................. 22

1. INTRODUCTION

First and foremost we at NDT Systems, would like to thank you for your purchase of the ALL NEW

Curlin- AIR, portable airborne ultrasonic flaw detector.

The Curlin-AIR has been designed for airborne non-contact or dry-coupled contact ultrasonic flaw

detection applications when used in conjunction with a special AT1 ultrasonic transducer.

The Curlin-AIR’s application is for nondestructively inspecting low-density materials, such as

polyurethane foam and other porous materials. It is not intended for inspecting high-density materials,

such as metal castings, plates, welds, or thick solid plastic (NDT Systems, standard QUANTUM TE

flaw detector is a better choice for these applications).

The primary mode of operation for the Curlin-AIR is through-transmission, using separate transmitting

and receiving transducers mounted in opposition on a hand held “yoke” (for scanning the material).

Used, in this fashion, the ultrasonic beam is transmitted through the material and detected on the

opposite side. Flaws are typically indicated by their property to “block/reflect” the transmission of the

ultrasonic beam (they tend to greatly reduce the “normal” signal amplitude).

In addition to the detection of localized flaws, the Curlin-AIR should also respond to density variations

in the material (sensitivity a function of the material type and degree of variation).

This manual serves two purposes. 1) Quick Reference and 2) Tutorial.

C The Table of Contents of this manual is actually a TABLE/INDEX. Each menu item is mentioned

here for quick easy access to a description of the menu item you may have a question with.

C Anywhere you are in the Curlin AIR’s menu you can get a description of the feature and how to

use it with a simple keystroke. Just highlight the menu item you want to use or have question

with and then press the SEL/HELP key for about 1 second.

C Chapter 2 deals with the menu, structure, and description of the features. This would be

recommended reading. There are quite a few images to help you better understand the

concepts.

Again, thank you for your purchase of the Curlin -AIR.

Basic System Components

The basic through-transmission system consists of.

• Curlin-AIR

• Two coaxial cables (flexible, heavy duty, small diameter with BNC to BNC connectors)

• One pair of identical AT1 transducers, interchangeable as a transmitter or receiver).

• One adjustable yoke for manually scanning the transducers.

2.0 Specifications

Display Super Twist LCD, 4.8 x 2.4 inches ( 122 x 61mm), transflective;

backlit, adjustable contrast, battery status and mode icons, large

thickness/soundpath display. Hollow or filled waveform, reversed

field selectable.

Display Mode Full-wave rectified.

Graticule Graphically Generated, 10 x 10 major divisions

Receiver 0.5 to 25 MHZ Broadband, Tuned 0.5, 1.0, 2.25, Frequency 5.0,

10.0 MHZ selectable.

Gain 115 dB; 1.0dB steps

Pulser Pulsed Continuous Wave, selectable from 1- 15 cycles

Linear Reject Linear to 90% maximum.

Range 1.0 inch (25mm) FS to 200 inches (5077mm) FS (steel equivalent).

Delay 0 to 150 inches (3807mm) FS (steel equivalent).

Velocity 0.0500 to 0.7500 inch per microsecond

Zero Adjust 0 to 3,000,000 nanoseconds, 50ns increment

Synchronization IP (Initial Pulse)

Transducer Modes THRU-TRANS (primary mode of operation), Pulse Echo, Pitch-

Catch,.

Display Mode Full-wave rectified; full-wave smoothed.

Flaw Mode One gate selectable; positive or negative threshold. Visible and

audible alarms triggered at pulse repetition rate. Gate start variable

over entire displayed range. Gate width variable from gate start to

maximum displayed range. Gate level adjustable from 1% to 99%

full screen.

Distance Mode Single echo distance measurement. Large digital readout.

Resolution 0.001 inch (0.01mm).

Stored Setups 50 user defined setups.

Screen Print Print current screen, including waveform, or complete setup.

Input/Output RS232 (9 pin D style); transfer setups to and from PC.

Units Inches or millimeters

Battery Pack Discharge time - 3.5 to 7 hours (ea), typical, depending upon display

back light usage.

Transducer Cable BNC Connectors.

Connectors

Size

Weight (Including Approximately 6.3 pounds

Battery Pack)

3.0 Operator Qualifications

The Curlin AIR's concept and design makes it the most unique ultrasonic flaw detector available.

In order for the owner of this advanced technology instrument to fully benefit from the unique features

of Curlin AIR, the assigned operator(s) must be experienced and well-founded in the fundamentals of

ultrasonic testing. Operators should fully possess the qualifications of ultrasonic testing personnel as

defined in Recommended Practice No. SNT-TC-1A, Personnel Qualification and Certification in

Nondestructive Testing, available from the American Society for Nondestructive Testing (ASNT), 1711

Arlingate Lane, P.O. Box 38518, Columbus, OH 43228-0518, phone (614) 274-6003, FAX (614) 274-

6899, telex 245347.

3.1Operational Notations

In order to simplify these instructions, certain consistent notations are used. In some cases, a

single key stroke produces a desired change; other changes may require a sequence of key strokes or

require continued key activation to "scroll" changes. The following terms and operational notations will

be used throughout. The operator is advised to become familiar with all of them.

KEYS

On the sealed membrane keypad are two types of keys: the arrow keys and the direct access

keys. In general, the arrow keys are multi functional, being used to change from one highlighted

menu item to another, or to increase or decrease or change variables. The direct access keys

and SEL/HELP keys are also multi functional, being used to select, or enter, a variable, or to

access the HELP screens.

VARIABLES

On analog-type ultrasonic instruments, a variety of knobs are available to change continuous

variables such as range, delay, gate positions, alarm levels, and reject. The same variables are

addressable in Curlin AIR; instead of knobs, holding down a key changes the variable.

SCROLLING

When a key is continuously depressed to change a variable, the effect is referred to as "scrolling".

Scrolling produces either a visible change in the display, a digital readout of the changing value of

the variable, or both.

TOGGLING

Toggling refers to the kinds of changes made by "toggling" switches on an analog-type instrument.

Functions such as OFF/ON, SINGLE/DUAL, and other discrete, limited value operations are

examples of toggling. With the Curlin AIR, toggling requires depressing a key to change a

function from one state to another (OFF/ON, for example), and again depressing the key to further

advance or reverse the discrete function.

CURSOR

This term refers to the means for notifying the operator which menu item, function or variable can

be currently acted upon. In the Curlin AIR, the cursor location is indicated by highlighting the

menu item. Changing the location of the cursor is accomplished by using the arrow keys. In

some menus, when that menu is exited, and later re-entered, the cursored item will be the one last

selected. In other menus, for operator convenience, the cursor defaults to a "home" item, the item

most often used in that particular menu.

NOTE:

The Curlin AIR is a type of computer in operation, relying heavily on it’s extremely sophisticated

software for much of it’s operation. Should the unit ever seem non-responsive to the front panel

keys or if the operator would like to set the instrument in the factory default use the following

keystrokes. First, turn the Curlin AIR off using the on/off key. If the unit won’t turn off in this

Curlin AIR

Menu Structure

Introduction Screen

Press Select For BackLight

(For Use In Dark Areas)

Software Version Number

-- MAIN MENU --

Energy 1-15

Blank Off, Track, Stay

BlnkAdj 0.1 -10 (X of Energy)

Delay 0 - 150

Gate Ampl / Distance

Level (see Amp or Dist)

Audio

MODE

(Amplitude or

Distance) see following "setup"

IF GATE AMPLITUDE

Alarm Off, POS, NEG

Start 0 - 200

Width 0 - 200

Level 10 - 90%FS

Audio On / Off

DISPLAY

Reject 0 - 90% FS

Display Solid, Hollow

Smooth On, Off

Grid On, Off

Freeze On, Off

Backlite On, Off

Contrast 0 - 100%

Beep On, Off

Lock On, Off

Pressing the MENU key repeatedly, produces the following menu flow.

IF GATE DISTANCE

Velocity .005 - .750"/us

Zero 0 - 3,000,000ns

Block .001 - 200

Level 10 - 90% FS

Hold Last, Min, Max

-- MISC --

Battery Test

Mode Thru / Echo

Units Inch/mm

Save 1 - 50

Recall 1 - 50

Print Screen, Setup

AlmTim 0.1 - 60 sec

PRF 6 - 125

MAIN MENU

5.0 MENU DESCRIPTIONS

One of the significant features of the

Curlin AIR is the Direct Access Keypad.

You can perform a simple calibration

without the use of any menus

whatsoever! Range and Gain are just

a single color coded keystroke

away.They are also, just about the

only keys you’ll need to calibrate the

Curlin AIR!! Also present on the

front panel are keys permitting the

user single stroke access to HELP,

MENU & FLAWgate menus directly.

5.1 Special Menu & Keyboard

As you read through this manual, the

MENU and arrow keys allow you to navigate

through the menu structure. Depressing the MENU key

repeatedly will cycle you through the various available menus

within the Curlin AIR. If you press the MENU key and hold it for

approximately 1 second a full list of the current instrument setup condition will be displayed. Using

the UP & DOWN arrow keys will allow you to scroll to any item in the setup list and then change

the value. This is convenient if you are entering a full setup manually which may be listed in a

calibration procedure. This also eliminates “menu hopping” which can be tedious in these

instances.

Help Screens

On Line Help is available for any menu item at any time. To access help on a particular function

just highlight the menu item and then press and hold the SEL/HELP key to read up to a full screen

of text explaining what the function is and how it’s used! HELP is also available from the full

screen setup mode by moving the highlight to the item and pressing SEL/HELP.

Menu Flow

The following represents the menu flow of the Curlin AIR. Pressing the MENU key repeatedly will

sequence through the menus as shown.

One key point to keep in mind is that HELP is always just a keystroke away. No

matter the menu item you are on or have question with, just Hi-Light the menu item

then press and hold the select key. A menu item description and use will pop up for

review. It’s almost like having a mini-manual built in.

Figure 4 - Main Menu

Figure 5 - Blank Adjust @ 10

With limited space available, some menu items are abbreviated. None-the-less, abbreviations

and acronyms represent terms familiar to qualified ultrasonic NDT personnel. Curlin AIR is based

upon a microprocessor, combining in high-speed digital electronic technology and new high capability

ultrasonic instrument features. The following is a description of each Menu item(s) and its associated

sub-functions.

5.2 MENUS

Three Menu items are arranged vertically along the left-hand margin of the display as shown in

the following Figure. Whenever a Menu is displayed, an active A-trace is also displayed. The

highlighted menu item can either be selected (to reveal related sub-functions) or changed by

appropriate keying of the arrow keys. In some highlighted Menu items, variables can be changed

without having to select sub-functions.

5.2.1MAIN MENU

The functions grouped in the MAIN menu are

used to select Curlin AIR basic setup

parameters. These items are logically among

the first to be addressed during a new setup.

Last setup /factory default values are

automatically displayed. Even though the

defaults permit many kinds of ultrasonic tests

using many kinds of transducers to be

successfully performed, precise flaw detection

tests may require refinements to the default

variables to better match material characteristics.

ENERGY

Energy allows the operator to adjust the energy of the pulse, in number of cycles, delivered to the

transducer. Values available are 1 - 15 cycles.

BLANK

Noise blanking, when selected, will blank any unwanted

noise after the first detected signal. BLANK ADJUST sets

the width of the signal to be accepted

before blanking the

balance of the waveform.

Example

C The gage is set to THRU MODE (through transmission)

which is the default mode. In the THRU mode, only the

first received signal is significant. There will be no multiple echos as in pulse echo or pitch

catch. Given this fact much of the trailing information as in Fig 3 is useless and in fact,

maybe a little confusing. Compare Figures 3, 4 & 5. In Fig 3, the BLANKing is turned OFF

and there is a fair amount of “signal” following the first peek envelope. The information past

this point is of little value. In Fig 4, the BLANK mode is turned on to TRACK and BlnkAdj

(BLANK ADJUST) is adjusted to a value of 10. In Fig 5 (next page) the BlnkAdj is set to 4.

Notice the width of the echo envelope and the elimination of any signal past the initial echo

Figure 7

Figure 6 - Blank Adjust @ 4

envelope. This feature has helped “clean” up the screen for easier interpretation.

When blanking is set to TRACK, the leading edge is the reference point for the blank

function. This allows the waveform to move horizontally on the screen (due to variation in

velocity or transducer spacing) while still maintaining the blank function relative to the leading

edge of the waveform. When blanking is set to STAY, the blanking will stay at the last

TRACKed position. If the echo moves to the right on the screen (further in time) it will

disappear into the BLANKed zone. The BLANKing and TRACKing take on fixed properties of

the BLANK while it was last in the TRACK mode.

BLNKADJ

Blank Adjust is used to adjust the width of the first signal

accepted before blocking the rest. The number shown is

based on the pulse ENERGY. A number of 2.0, for

example, sets a width two times the time of the pulse.

Selections include:

GAIN

Gain is available from the front panel. This function is used

to adjust the amplitude of the A-trace display. Increasing or Decreasing the GAIN will cause the

A-trace signal to increase or decrease in amplitude.

RANGE

Range is available from the front panel, This function is used to determine how much time

(distance) is represented on the horizontal axis of the A-trace display. Increasing or Decreasing

the RANGE will cause the A-trace display to expand or contract.

DELAY

Used to adjust the start of the A-trace display along the horizontal axis. Gates that are

synchronized with the A-trace will also delay accordingly.

GATE

MEASUREMENT GATE is used to select the type of

inspection to be performed.

C AMPLITUDE mode enables the use of the flaw

amplitude gate and alarm(as seen in Fig 3). Note that

ALARM follows GATE on the menu in this mode.

C DISTANCE gate enables the distance measurement

gate and

calibration settings as seen in Fig 6. Note that

VELocity and ZERO follow DIST. Setting of GATE.

IF IN AMPLITUDE MODE (refer to Fig 7)

ALARM POLARITY

C OFF

: ALARM enables or disables the FLAW gate alarm.

C POSitive

alarm means alarm activates when the signal exceeds threshold in gate.

C NEGative

alarm means alarm activates when signal drops below gate threshold

START

GATE START allows adjustment of the horizontal position of the leading edge (start) of the gate.

Continuously adjustable from 0.000 to 200.0 inches (500mm).

WIDTH

GATE WIDTH allows adjustment of the horizontal position of the trailing edge (width) of the gate.

Continuously adjustable from 0.000 to 200.0 inches (500mm).

1010

Figure 8 - DISPLAY MENU

LEVEL

GATE level allows adjustment of the threshold level of the gate. Adjustable from 10% to 90% of

full screen height in 1% increment.

IF IN DISTance MODE (refer to Fig 8)

VELOCITY (VEL)

Sets the material velocity (inches/microsecond or mm/microsecond) used in calculations of

thickness. NOTE: The VELOCITY value will be decreased by approximately one-half from

reference velocity when ANGLE MODE is selected.

ZERO ADJUST (Zero)

A fine delay function which allows for compensation of transducer wearsurfaces, coupling

membranes and angle beam wedge. Adjustment is continuous from 0 to 300,000 nanoseconds.

BLOCK

BLOCKING GATE is used to Increase or Decrease the length of the gate that is used to block

out any unwanted signals after the Initial Pulse. Adjustment of the BLOCKING GATE will allow

proper setup for IP to first echo measurement in the distance mode. This is used if there is any

spurious noise between the IP and “real” received echo.

LEVEL

DISTance Gate Threshold allows Increase or Decrease the Measurement Threshold level. Any

echo with amplitude equal to or greater than the Thickness Gate Threshold will be measured.

The threshold gate is the bar on the left of the A-Trace frame extending to the first echo in the

figure. This is the vertical point on the echo envelope used for the DISTance measurement.

AUDIO

When AUDIO is On, the audible annunciator will sound when an alarm is activated. When

AUDIO is off, no sound is generated for alarms.

5.2.2 DISPLAY MENU

The functions grouped in the DISPLAY menu are primarily

used to select display related functions. Generally these will

be user preferences, with little, other than REJECT,

affecting calibration.

DISP

DISPlay - There are two selectable screen displays:

C HOLLOW When selected, displays a black lined, hollow A-

trace waveform against a light background.

C SOLID When selected, displays a black filled A-trace waveform against a light background.

SMOOTH

Smoothing, or averaging, is optionally performed on the waveform by setting each point to be the

average of itself and the point before and after it.

GRID

Turns the background grid on or off. Two types of grids can be displayed, Normal or Numbered.

1111

Figure 10 - Hollow DISP

Figure 11 - Hollow Smoothed

Figure 9 - Hollow, Smoothed, No Grid

Figure 13 - Solid, Smoothed, No Grid

Figure 12 - Hollow, Grid, Numbers

SAMPLES OF VARIOUS DISPLAY SCHEMES

FREEZE

When activated stops any screen activity and “holds” whatever was on the screen at the time the

freeze option was selected. Activate the function by using the left & right arrow keys.

BACK LIGHT

Allows On or Off selection of the Back light. Turn the Back light On to operate in low ambient

lighting conditions. The Back light can be switched Off during bright ambient lighting conditions

to save power.

CONTRAST (CONTR)

Adjusts the contrast of the LCD display for best possible viewing. Continually adjustable from full

white to full dark.

BEEP

When BEEP is On, the audible annunciator will sound when a key is pressed or when the user

inputs an erroneous value. If the beep is Off, no sounds are generated for these conditions.

LOCK

When selected, will lock out key pad functions from inadvertently being activated.

5.2.3MISC Menu

BATTERY TEST

Displays the Battery gage and informs the user of the battery charge status. Press SEL/HELP to

view current battery status

MODE

Used to select the correct distance display, according to the probe configuration. THRU shows

the correct distance when the transducers face each other ( through transmission ), and ECHO

shows the round-trip distance when they are side by side in a pitch catch configuration.

UNITS

Allows selection of the basic unit of measurement for the gage. Select between INCHES or

MILLIMETERS.

SAVE SETUP

1212

Figure 14 - Save Location

Stores the Ultrasonic setup currently in use. 1 - 50

setups can be stored. A user defined, 16 char

comment can be applied to each saved setup. When

the cursor is on the SAVE or RECALL field the

comment for that setup is displayed on the status line.

The parameter LIST allows the user to see and select

from a list off all stored setups with their comments. To

Save a setup, follow these stepes:

C Cursor to SAVE

C Press the right &/or left arrow keys to locate an

available position (1-50). Used setup locations will display a user defined setup name in the

status line (line available above A-Trace). The status line will normally display the receiver

MODE.

C If an attempt is made to save “over” an existing location, a message will be displayed asking

for verification to overwrite the existing setup.

C When an available location is found, a screen as shown in the previous figure prompting for

an alpha-numeric setup name. To name the setup, use the up, down, left & right arrow keys

to scroll to a character (for example, highlight menu item A - Z and press the right arrow key

until the letter C is displayed) and then press SEL/HELP to select the desired character.

C Continue this operation up to 16 characters to fill in the setup name line.

C Scroll down to SAVE and press SEL/HELP

C An exit from the save menu will be performed and the setup name will be displayed in the

status line.

Rcall

Recalls any ultrasonic setup stored in memory. This includes the Factory Default setup (NEW) or

any of the other 50 instrument setups. Note: If the gage is powered ON with the SEL/HELP

button depressed, the Factory Default setup will be loaded. When the cursor is on the SAVE or

RECALL field the comment for that setup is displayed on the status line. The parameter LIST

allows the user to see and select from a list off all stored setups. Use the left & right arrow keys

to move through the list in sequence or, set Rcall to list and press select. A list showing setup

number along with alpha numeric name will then be displayed. Scroll down through the list to

select the desired setup and press SEL/HELP

SCREEN

Allows selection of PRINT SCREEN. PRINT SCREEN, when selected, toggles the screen

printing mode on or off. When the screen printing mode is on, any screen displayed may be

printed by pressing and holding the MENU button. To cancel the screen print function, press the

SEL/HELP button while the cursor is on the PRINT:SCREEN field

SETUP

When highlighted allows the user to print the current to a serial (RS-232) printer or to a file. When

the desired setup is loaded, press the SEL/HELP key.

AlmTim

ALARM TIME: Alarm ON time: This sets the amount of time ( in seconds ) the alarm will stay on

even after a single pulse triggers it. Adjustable from 0.1 seconds to 60 seconds.

PRF

Pulse Repetition Frequency : This is the frequency ( number of times per second ) at which the

system pulses the transducer, and collects thickness / amplitude readings.

1313

6.0 Curlin AIR SETUP AND OPERATING CONSIDERATIONS

6.1 Safe Operation

Always use this electrical equipment in a safe manner, including the practice of all the SAFETY

PRECAUTIONS listed earlier in this manual, as well as applicable local and company specific

safety regulations.

6.2 Safe Inspection Site

Always choose an inspection site (including it’s atmosphere) that is safe, in accordance with the

warnings presented in the SAFETY PRECAUTIONS section of this manual, as well as any

applicable safety regulations.

6.3 Ambient Ultrasonic Noise

The Curlin-AIR operates in the relatively low ultrasonic frequency range in order to achieve its

desired performance characteristics. In this regard, the Curlin-AIR has been electronically

designed to reduce or suppress interference effects that might be caused by ambient sonic and

ultrasonic noise occurring in the vicinity of the inspection site. Such interference can detrimentally

affect the inspection reliability performance (such as flaw detectability, alarms, flaw gate and

display).

Typically, it is unlikely that ambient ultrasonic noise should be a problem. However, it is highly

recommended that the selected inspection site be checked prior to performing any actual testing.

One good check method is to first “calibrate” the Curlin-AIR on a reference sample flaw (see prior

calibrating instructions). Next turn the instrument’s power OFF, disconnect the transmitter coaxial

cable from the front panel BNC connector and, then, turn the power ON again. Now, simply

watch the display and flaw alarms for any noticeable intermittent or continuous ultrasonic “static”

(noise pick-up). It is recommended that this setup be monitored long enough time wise to obtain

a reliable assessment of the inspection site for the possible presence of interfacing levels of

ambient ultrasonic noise.

It is not advisable to perform any inspection in the presence of unacceptable levels of ambient

ultrasonic noise. The primary problem with the excess noise levels is that the likelihood of false

indications will be high. In the unlikely event that such noise is observed, it will be necessary to

either move the inspection site to an acceptable, noise free location, acoustically shield the

vicinity adjacent to the ultrasonic beam or determine the source of and prevent the ultrasonic

noise.

6.4 Calibrate Before Performing Any Inspection !!

Always calibrate the Curlin-AIR system with a reference sample(s) in accordance with the

instructions previously given in this manual prior to actual inspection use. Also, check calibration

occasionally during inspection to be sure the system is operating properly.

6.5 Reference Samples

As with all nondestructive testing instrumentation, a satisfactory sample of the material being

tested, containing the minimum-size and type of flaws to be detected, must be used to properly

adjust the detection level of the Curlin-AIR prior to actual use. Operating without such reference

samples will only yield unknown and uncontrolled performance levels.

6.6 Operational Considerations

For experienced Level I or Level II ultrasonic inspectors, setting up and operating the Curlin AIR

will be little different from analog-type ultrasonic instruments. Instead of using knobs and

switches for control adjustments, the appropriate menu item must be found, then selected, then

controlled by using one or more of the keys.

For persons unfamiliar with fully micro computerized instruments, perhaps the most frustrating

part of learning is in the finding

the item they wish to control. In designing the menus for the

1414

Curlin AIR, particular attention has been paid to minimizing the number of menus and simplifying

the process of locating desired functions. To some extent, once the operator is familiar with the

operation, digitally controlled instruments are easier, more intuitive to operate than analog types.

6.7 Curlin AIR Display Characteristics

A difference noticed by experienced operators of analog-type instruments is in the "stair-step"

appearance of the display on instruments having digitally derived pixel-type displays, especially

at relatively short ranges of the time base. There are two aspects of this type of display that

should be considered:

1. The effect on determining vertical linearity, and

2. The effect on the appearance

of horizontal linearity.

Horizontally, the Curlin AIR A-Trace area, exclusive of the menu area is 170 pixels wide.

However, because of the way a smoothly curved analog waveform is sampled by analog-to-

digital circuitry, "stair-stepping" can produce the appearance of being less smoothly shaped.

This effect is visual only, being more pronounced when the time-base is at short range.

However, the determining factor regarding horizontal linearity is in the digital sampling rate, not in

the actual visible appearance. Because distance/thickness readouts in Curlin AIR are

determined from a Hi-Speed sampling or “digitizing” rate, the digital readout has inherent

accuracy and resolution far superior to that which can be measured visually from a conventional

CRT. Even at modestly short ranges, measurements made visually from Curlin AIR’s display are

essentially equivalent to those made from CRTs. Curlin AIR’s thickness readouts are precise,

regardless of the range or stair-stepped appearance of the A-trace display.

Within a short time of familiarization with Curlin AIR’s display and alarm systems, the operator

will adapt to the display and will especially appreciate the large area and visibility of the A-trace.

Most experienced operators of analog-type instruments can effectively operate the Curlin AIR

without reference to the Operator's Manual. However, some of the procedures outlined below

will guide the operator in quickly setting up and using the many features incorporated in Curlin

AIR that are not found in many "standard" ultrasonic instruments. The versatility of Curlin AIR

will be readily evident by following the procedures described below.

6.8 Factory Setup Variables

When the Curlin AIR is turned on by pressing the ON/OFF control, the LOGO screen is

displayed automatically. When the gage is operated for the first time, or if FACTORY DEFAULT

is selected from memory, all the control variables "default" to specific values (After that they will

display the last previous setup parameters). For many common thickness gaging applications, it

is only necessary to "fine tune" a few variables. Some applications can be started without any

adjustments. The FACTORY setup variables have values that match or nearly match a variety of

the most commonly used transducers for thickness gaging. By pressing any key to continue, then

by depressing and holding the MENU key the FACTORY setup default variables are displayed.

1515

7.0 Flaw Detection Procedures

7.1 Mechanical Assembly

Be sure power is turned off before you connect or disconnect the transducers from the

instrument.

7.1.1 Attachment of Transducers

Attached the AT1 transducers to the screw-on connectors or clamp assembly end of the yolk.

The transducers are identical and interchangeable.

7.1.2 Adjustment of Yoke

Adjust telescopic arms of yoke to fit width of material to be manually scanned. Adjust air gap

between the yoke arms so the gap is satisfactorily large enough to accommodate the thickness

of the material to be scanned. Align transducers so they are precisely opposite one another by

using the various rotation and linear adjustments provided by the yoke and adapters.

7.1.3 Cable Attachment to Curlin-AIR

With Curlin-AIR’s power turned OFF

, connect the cables to the BNC coax cable connectors

located on the lower right-hand corner of the Curlin-AIR’s front panel.

7.2 Electronic Initialization & Checkout

7.2.1 Power-ON.

Turn on the Curlin-AIR by pressing the green/red button in the lower left-hand corner of its front

panel.

7.2.2 Message Display

The first message on the display screen will ask you to select or not select to use a backlit

screen (for use in darkened areas). Follow the screen prompt/instructions.

7.2.3 Automatic Initializing Set-up

By pressing any button after the battery check screen appears will automatically adjust the

instrument so it displays a “reference air A-scan” pulse and Flaw Gate alarm on the screen.

This automatic “default” program assures you that the system is basically operational. At this

point, you can adjust (and practice) changing ultrasonic pulse signal by adjusting the GAIN and

RANGE controls on the front panel. Also, the DELAY menu function allows you to scroll the

pulse across the baseline without expanding or compressing the signal (in contrast to the

RANGE control). Move your hand or some object through the ultrasonic beam and note the

disruption of the signal on the screen and triggering alarms. Also note the beam diameter in a

similar fashion..

7.2.4 Insert Material Into Beam

Place the material under test into the ultrasonic beam, or move the yoke over the material.

Orient the ultrasonic beam (transducers) so it is as perpendicular

as possible to the surface of

the material. This is the required alignment for inspection and is called “NORMALIZING THE

BEAM”. Adjust (increase) the GAIN until you obtain a pulse signal of reasonably high amplitude

(greater than 75% of screen height). Adjust the RANGE (if necessary) and/or DELAY controls

to conveniently position the signal along the baseline For preliminary checkout, satisfactorily

position the horizontal location/width and the vertical location (alarm trigger level) of the FLAW

GATE on the signal (see adjusting the FLAW GATE). Slowly scan the ultrasonic beam across

the material to develop a “feeling” to maintain beam alignment (as perpendicular as possible)

and handling of the yoke. Watch the pulse on the display while scanning, keeping it “peaked”

by maintaining perpendicular beam alignment with the yoke. (In actual inspection work, the

FLAW GATE is adjusted to automatically trigger the alarm whenever a detected level of flaw

signal occurs, thus, eliminating the need to constantly watch the screen display).

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NDT Systems Curlin-Air User manual

Brand: NDT Systems

Model: Curlin-Air

Type: User manual

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NDT Systems Curlin-Air User manual

NDT Systems Curlin-Air User manual

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