OmniScan MX2 Training Program Introduction to Phased Array Using the OmniScan MX2

Part 2

Please send questions and comments to: PhasedArraySupport@olympusndt.com

Introduction to Phased Array Using the OmniScan MX2 Part 2 - Overview Ø  Supporting documentation for the training program comes primarily from the MX2

software manuals and the Olympus reference manuals below. Ø  Modern phased array systems like the MX2 do not require an advanced knowledge

of mathematics or acoustic theory and the training program focuses on practical explanations and real world application examples for the working inspector.

Ø  Supporting theory, mathematical formulas, and more advanced PA concepts can be found in the books below available from the ONDT web site.

Ø  These manuals can be downloaded at http://www.olympus-ims.com

3

Introduction to Phased Array Using the OmniScan MX2 Part 2 - Review

Ø  Phased array calculators differ in functionality and complexity as a result of supporting different types of probes, wedges, and applications.

Ø  The most simple or complex phased array calculators can generally be divided into 4 specific sets of parameters: §  Probe parameters. §  Wedge parameters. §  Material parameters. (Velocity) §  Focal law beam formation.

Ø  3 parts hardware and 1 part software to generate the focal laws. Ø  For proper formation of the focal laws, all hardware parameters must be configured

correctly, and the beam formation requested must be within the limits of physics, the hardware, and the instrumentation.

4

Introduction to Phased Array Using the OmniScan MX2 Part 2 – Probes Review

Ø  1D Linear array probes are the most widely used for industrial inspection and the only type that is supported directly in the OmniScan MX2 software wizards.

Ø  Phased array probes other than 1D linear must use focal laws generated from an external calculator for import into MX2.

5

Intro to Phased Array Using the OmniScan MX2 Part 2– System Software

Ø  Current MX2 software and updates can be downloaded directly from the Olympus website at www.olympus-ims.com.

Ø  Software update notification will be emailed directly to you when available after enrollment in the notification program on the web site.

6

Intro to Phased Array Using the OmniScan MX2 Part 2– Hardware Modules

Ø  The OmniScan MX2 is compatible with all new and previous generation phased array modules from 16:64M to 32:128PR. The open architecture is designed to also support the next generation of advanced phased array modules and software.

7

Intro to Phased Array Using the OmniScan MX2 Part 2 – Power Supply

Ø  The OmniScan MX2 like all sophisticated electronics requires a clean grounded power supply.

Ø  Although the OmniScan MX2 comes with a power supply designed to be used in industrial environments, verification of the wall outlet power is highly recommended both for electronic protection, battery health, and elimination of electrical interference or “Noise” in the UT data as pictured below.

Electrical noise on C-scan and S-scan due to ungrounded external power source.

8

Intro to Phased Array Using the OmniScan MX2 Part 2 - Touch Screen Ø  The OmniScan MX2 touch

screen eliminates the need for external peripheral mouse, keyboard, keypad to allow fast navigation and software configuration directly on the display.

Ø  Functions of the touch screen include: –  All menu and sub menu

navigation. –  Zoom and pan features. –  All gate and cursor functions. –  All text and number input fields. –  All parameter selection. –  Toggle between readings list 1

and 2 on the main display.

9

Ø  Selecting the help key will display the section of the online manual relative to where you are at in the software menu.

Ø  The scroll knob allows navigation in the on line help manual.

Ø  Selecting the help key a second time will return the display to normal operation.

Intro to Phased Array Using the OmniScan MX2 Part 2– Help Key

10

Intro to Phased Array Using the OmniScan MX2 Part 2 - Touch Screen Modes Ø  The icon in the upper corner indicates the active data window and touch screen

mode. Ø  The MX2 touch screen has 3 modes of operation:

1.  Zoom Mode. Default display mode and enabled with the Zoom function key. Allows touch screen zoom and pan on data window.

2.  Gate Mode. Enabled from the gate function key. Allows touch screen manipulation of all gate functions on A-scan and S-scan data windows.

3.  Cursor Mode. Enabled from the cursor function key. Allows touch screen manipulation of all cursors.

Ø  The data cursor on the S-scan and C-scan is always active regardless of touch screen mode.

Zoom mode Gate mode Cursor mode

11

Intro to Phased Array Using the OmniScan MX2 Part 2– Zoom Mode Ø  By default the MX2 is in zoom mode until gate or cursor mode is selected. Ø  In the active data window, forming a box with one finger and releasing will zoom the

defined area. Touch and drag vertical or horizontal will allow zoom in one axis. Ø  Tap on the zoom icon to enable pan mode. This function allows a zoomed window to

be repositioned with one finger. Ø  The pan feature is useful for centering zoomed data or for panning through a long

inspection on the scan axis in short windows of a predetermined length typical of PA weld and TOFD one line scan inspections.

Ø  While in zoom mode, gates and cursors are disabled on the touch screen.

12

Intro to Phased Array Using the OmniScan MX2 Part 2 – MX2 User Interface

Ø  The MX2 user interface and display is divided into the following sections: 1.  Main menus. 2.  Sub menus. 3.  Parameter input. 4.  Data view windows. 5.  Header and readings area. 6.  Indication status area.

1

2

3

4

4

4

5 6

13

Intro to Phased Array Using the OmniScan MX2 Part 2– Part and Weld Wizard

Ø  Each step in the wizard process is completed prior to selecting next. Below is the entire wizard sequence.

14

Intro to Phased Array Using the OmniScan MX2 Part 2 – Material Thickness

Ø  The material thickness is not directly related to the focal law formation but is necessary for the skip lines on the A-scan and S-scan, and the trigonometry readings such as DA (Depth of signal in gate A).

Ø  Material and material thickness are entered during the part wizard process and can also be modified in Group\Probe\Part>Part submenu.

Ø  Material Thickness can be changed at anytime without affecting the beam or calibration.

15

Intro to Phased Array Using the OmniScan MX2 Part 2– Material Velocity

Ø  The material selection is relative to velocity and associates both the shear and longitudinal velocity for use later in the focal law section of the wizard.

Ø  Use of materials that are not in the database must be entered directly in UT Settings>General>Velocity.

Ø  The velocity of the material and wedge are essential parameters for the focal law calculator and beam forming. Angle 1 degree angle accuracy and proper beam formation the material velocity must be within +\- 50 meters per second of the real velocity. 25-70 degrees shear has < 12 meter/sec velocity deviation

16

Intro to Phased Array Using the OmniScan MX2 Part 2 – CSC Mode

Ø  CSC (Circumferential scanning mode) is relative to the trigonometry readings such as depth (DA) and surface distance (PA).

Ø  The COD inspection for the OmniScan MX2 requires that the focal laws be built with an external focal law calculator and imported into the OmniScan MX2 for use.

Ø  Only plate is supported directly in the MX2 software. Ø  A pipe to pipe girth weld in skew 90\270 inspection is considered plate because the

ID and OD surfaces on parallel.

17

Intro to Phased Array Using the OmniScan MX2 Part 2 – Group Setup Wizard

Ø  Each step in the wizard process is completed prior to selecting next. Each task is explained in the next series of slides. Below is the entire group setup wizard progression.

18

Intro to Phased Array Using the OmniScan MX2 Part 2 - Group Overview Ø  The MX2 is capable of eight groups that can be any combination of phased array,

conventional PE, or conventional PC (Pitch-catch) including TOFD. Ø  The total of all A-scans or focal laws on all groups cannot exceed 256. Ø  For two-probe two-sided inspections the “Copy group” function can be used to

create a mirror group identical to the first where only the skew and offset need be changed.

Ø  There are three possibilities for group creation that are related to what type of probe and connector is used, and what type of module is available:

1.  Phased array group using the PA connector. 2.  Conventional UT using the PA connector through an adaptor. (See conventional UT section) 3.  Conventional UT using the BNC connectors of a compatible module. (First generation modules do not

allow simultaneous use with PA. See conventional UT section)

19

Intro to Phased Array Using the OmniScan MX2 Part 2 - Probe Selection

Ø  Probe selection is available in the setup wizard and the Menu>Group Probe\Part>Probe submenu.

Ø  The MX2 will read the following information from the chip in the connector of Olympus probes when the probe auto detect is on:

1.  Probe Model. 2.  Probe Frequency. 3.  Probe Element Quantity. 4.  Probe Element Pitch. 5.  Reference Point. 6.  Serial Number (Not displayed).

Ø  This allows rapid population of the group wizard (Focal law calculator) and ease of use.

Ø  With auto detect off, custom and probes from manufacturers other than Olympus can be entered and saved in the MX2 database.

20

Intro to Phased Array Using the OmniScan MX2 Part 2 – Wedge Selection

Ø  Wedge selection is available in the setup wizard and the Menu>Group Probe\Part>Wedge submenu.

Ø  Wedges are selected from a database. Ø  New or custom wedges can be created

and saved. Ø  This allows rapid population of the group

wizard (Focal law calculator) and ease of use.

Ø  Care must be taken for wedge selection as one wedge may have many entries based on probe model and probe position for the same housing type.

21

Intro to Phased Array Using the OmniScan MX2 Part 2 - Probe Position

Ø  For manual inspection where the probe position is controlled by the user and not a scanner, these variables are not required or relevant and the default values should be accepted.

22

Intro to Phased Array Using the OmniScan MX2 Part 2 – Focal Law Wizard Ø  Each step in the wizard process is completed prior to selecting next. Each task is

explained in the next series of slides. Below is the focal law wizard progression.

23

Intro to Phased Array Using the OmniScan MX2 Part 2– Beam Steering Limits

Ø  Beam steering is limited by the probe element size and aperture, the wavelength, physics of UT (Snell’s law) and most importantly, the ability to calibrate each A-scan in the group to the satisfaction of the application or procedure.

Ø  The calibration process, like conventional UT, includes maintaining the velocity at a known angle (Does not mode convert) and ability to correct the wedge delay, sensitivity, and build a TCG (If required) for every A-scan in the group.

24

Intro to Phased Array Using the OmniScan MX2 Part 2 – 1st Element Position

Ø  The position of the beam set within the probe is defined by the first element position.

Ø  For probes with a large element quantity (64, 128) the aperture can be programmed at any position.

Ø  It is a common inspection strategy to use two sector scan groups from the same probe for coverage. One from the front of the probe for 1st leg coverage of the ID (First element position 49), and one from the back of the probe for 2nd leg coverage of the OD (First element position 1).

Element 1

Element 49

25

Intro to Phased Array Using the OmniScan MX2 Part 2 – Probe 1st Element Question:

For manual inspection is it better to program the sector scan at the front or back of the probe\wedge?

Answer: The front of the wedge. In the example below using a start element position of 49 allows the 16 element aperture beam to exit the wedge as close to the weld as possible.

Element 49 is the last element on the probe that will still allow a 16 element aperture. Total probe elements (64) – aperture (16) + 1 element = maximum first element position (49).

First element 49

26

Phased Array Using the OmniScan MX2 Part 2 – Probe Element Quantity

27 elements × .6 mm pitch probe = 16 mm aperture (32:XXX) 16 elements × 1 mm pitch probe = 16 mm aperture (16:XXX)

Ø  Below we see two examples that demonstrate the benefit of more elements of a smaller pitch with the same size aperture. (16:XXX vs. 32:XXX)

Ø  The signal in the red gate A is a crack tip of a 20% through wall ID connected crack in a 25mm thick carbon steel weld. The gain is increased so that the crack tip signal is at 80% amplitude.

Ø  The 32:XXX acquisition module example shows a clear improvement in sizing accuracy by producing a clearer image of the crack tip and improved signal to noise ratio than that of a 16:XXX acquisition module.

Ø  Using more elements of a smaller pitch required a probe with more elements and a compatible acquisition module for the MX2 with more pulsers.

27

Phased Array Using the OmniScan MX2 Part 2 – Beam Min and Max Angle

Ø  Beam steering is limited by the probe element size and aperture, the wavelength, physics of UT (Snell’s law) and most importantly, the ability to calibrate each A-scan in the group to the satisfaction of the application or procedure.

Ø  The phased array calibration process, like conventional UT, includes maintaining the velocity at fixed angles (Does not mode convert) and ability to correct the wedge delay, sensitivity, and build a TCG (If required) for every A-scan in the group.

28

Phased Array Using the OmniScan MX2 Part 2 – Beam Angle Step Resolution Ø  Below the affect of beam angle resolution for a typical 45-70 degree S-scan on a

30mm V weld is displayed. Ø  Beam angle resolution is directly related to sizing accuracy and ability to characterize

flaws. Ø  The ability to distinguish between a crack and root non-fusion, or porosity and lack of

fusion is greatly enhanced by a higher A-scan density within the S-scan. Ø  For inspections where flaw characterization and sizing is not a consideration the

scan speed and file size can be optimized by reducing the angle resolution to 1 or 2 degrees creating fewer A-scans within the S-scan.

45-70 degree S-scan at 1 degree resolution 45-70 degree S-scan at 1/2 degree resolution

29

Phased Array Using the OmniScan MX2 Part 2 – Beam Angle Step Resolution Ø  In this example there are 4 groups of phased array data and 4 groups of TOFD data

to provide 1mm detection and sizing for a 100mm thick ASME vessel inspection. Ø  The two phased array groups covering the ID are at a 1 degree resolution. Ø  The two phased array groups skipping off the ID for OD coverage are at a ½ degree

resolution. Ø  Because the OD coverage groups have a longer sound path, the groups are

programmed at ½ degree resolution (2X as many A-scans) to maintain the same sizing ability as the ID groups.

30

Phased Array Using the OmniScan MX2 Part 2– Beam Angle Step Res.

Ø  The image to the right is a crack tip detected at the same scan sensitivity for a 1 degree resolution and a .25 degree resolution sector scan group.

Ø  The ability to size and characterize flaws is improved with the increased A-scan density within the sector scan.

Ø  The .25 degree resolution group will more clearly locate and size the crack tip data due to more A-scans within the same angle range (45-65 degrees).

31

Intro to Phased Array Using the OmniScan MX2 Part 2 – Inspection Focus

Ø  The OmniScan MX2 focal law calculator only supports depth focusing and un focused group.

Ø  Sound path, projection, and focal plane focusing can be imported into the OmniScan MX2 from an external focal law calculator using the memory card.

32

Intro to Phased Array Using the OmniScan MX2 Part 2 – Inspection Focus

Ø  The majority of OmniScan MX2 applications including weld inspection are well suited for depth focusing and do not benefit significantly from other focus strategies.

Ø  An example of an application that would benefit from a specific focal plane other than depth is the dissimilar metal weld inspection in inconel using a low frequency longitudinal angle beam sector scan for maximum penetration and focus on the far side weld bevel.

33

Intro to Phased Array Using the OmniScan MX2 Part 2 – Beam Focus

Ø  In phased array inspection, the beam size, angle, and focal plane are capable of being manipulated within the limits of physics, the software, and the hardware.

Ø  The OmniScan MX2 only supports depth focusing. Ø  Focusing of any other type can be achieved by importing the focal laws from an

external calculator. Ø  The maximum distance that the beam can be focused is defined by the near field

calculation below. Ø  Any number entered into the focus depth field that is greater than the near field will

result in an unfocused beam.

34

Intro to Phased Array Using the OmniScan MX2 Part 2 – Beam Angle and Exit Ø  Beam steering angle (Refracted angle) is verified in phased array inspections exactly

like conventional UT. Ø  The beam steering limits of a particular probe\wedge\aperture is reached when the

highest and lowest angle of the group are not able to be verified within 1 degrees. Ø  The real exit point of the beam is verified with an IIW block and compared with the

calculated value in the software. Once the exit point is validated the angle can be verified on the other side of the IIW block.

Ø  This process is explained in detail a later section. Repeat….exactly like UT.

Exit point of beam

Index offset calculated by software and verified on IIW block

40 degree A-scan 40 degree A-scan

Verified exit point is used to measure real angle in material (40 degrees)

35

Intro to Phased Array Using the OmniScan MX2 Part 2 –Verification of Beam

Ø  In addition to standard IIW and similar calibration blocks, there are industrial standards such as ASTM E2491 that specify techniques and calibration block designs for verification of the phased array beam profile.

Ø  Beam profile, beam steering limits, beam focusing, element activity, etc can be verified similarly to the requirements of conventional UT with specialized reference standards.

36

Intro to Phased Array Using the OmniScan MX2 Part 2 - UT Configuration Ø  After completion of the part\weld and group setup wizards, the focal laws are created

and the UT parameters can be configured. Ø  Parameters of the UT menu are relative to the acquisition modules which are

available in different configurations. For different acquisition module specifications refer to the user manual.

Ø  The UT menu and submenus are similar to any modern conventional UT instrument with the exception we will be managing many focal laws or A-scans within the group and not just one. All of the same basic principles apply for PRF, point quantity, etc.

37

Intro to Phased Array Using the OmniScan MX2 Part 2 - Gain Function Key

Ø  The gain function key is circled in red below and can be accessed in the UT>General sub menu.

Ø  A short stroke of the gain function key enables the gain parameter to be modified in the upper left display.

Ø  A long stroke of the gain function key opens the UT>General sub menu.

38

Intro to Phased Array Using the OmniScan MX2 Part 2 - UT Range

Ø  Within the group, the start and distance of the UT range is entered in one place for all focal laws. (UT>Start and UT>Range)

Ø  The UT range is set depending on the UT mode selected in Display>UT Mode>TD, SP, or Uncorrected. The MX2 default and most common mode is true depth.

Ø  When setting the UT range, the useful part of the digitized A-scan is optimized by adjusting the range over the area of interest of the inspection.

Ø  Adjusting the range efficiently allows proper gate position for trigonometry readings and C-scan creation.

Ø  Poor range selection is a common mistake that results in missed data, poor A-scan resolution, and low PRF.

39

Phased Array Using the OmniScan MX2 Part 2 - UT Range Function Keys

Ø  There are two function keys associated with the UT range: 1.  Start key. Sets the start position of the digitized A-scan. 2.  Range key. Sets the range distance from the start position of the digitized A-scan.

Ø  A short stroke of either function key enables the parameter in the upper left display. Ø  A long stroke of either function key opens the UT>General sub menu.

40

Intro to Phased Array Using the OmniScan MX2 Part 2 - UT Pulser

Ø  The pulser sub menu is similar to a digital conventional flaw detector and is used to set the A-scan waveform view by adjusting the following parameters: –  Pulser (Uneditable for PA and UT pulse\echo inspection or when

auto program is on). –  TX\RX mode (PE, PC, TT, TOFD). –  Probe frequency (Only enabled when unknown probe is used). –  Energy Voltage. –  Pulse width. –  PRF (Pulse repetition frequency).

41

Intro to Phased Array Using the OmniScan MX2 Part 2 – Digital Filters

Hig

h pa

ss

Low

pas

s

Band pass

Ø  The MX2 has a series of preset digital filters that include low pass, band pass, high pass, and none.

Ø  Like in conventional UT, the receiver filters are used to improve signal to noise ratio by cropping off portions of the probe’s bandwidth.

Ø  Filters will decrease amplitude significantly but increase the signal to noise ratio and should be selected prior to calibration.

42

Intro to Phased Array Using the OmniScan MX2 Part 2 – Video Filter

Ø  The video filter enables digital smoothing based on the probe frequency and is only available in FW, HW+, and HW- rectification mode. (Not RF mode)

Ø  The video filter is not available on the 32:128PR module when in PC mode.

43

Intro to Phased Array Using the OmniScan MX2 Part 2 - UT Beam Parameters

Index Offset

Refracted Angle

44

Intro to Phased Array Using the OmniScan MX2 Part 2 – Point Quantity

Ø  The higher the point quantity the better the resolution on the A-scan. Ø  The point quantity is a compromise between file size and A-scan resolution. Ø  320-640 points is sufficient for the most common inspections and ensures precision

readings.

45

Intro to Phased Array Using the OmniScan MX2 Part 2– S-scan Overview Ø  The true depth S-scan display is the primary display used in phased array inspection

for flaw characterization, volumetric location, depth and height sizing. Ø  The S-scan allows all focal laws (A-scans) for the group to be viewed in one display

corrected for true depth or uncorrected, and superimposed over a weld overlay.

46

Phased Array Using the OmniScan MX2 Part 2 – Current Law vs. All Laws

Ø  When the S-scan UT mode is set to true depth, the interaction with the UT range can be set to the following two options under depth:

1.  Current focal law (Pictured left). 2.  All focal laws (Pictured right).

Ø  When the depth mode is set to current focal law, the range is set for the current law (A-scan) and extrapolated in sound path to the rest of the laws.

Ø  When the depth mode is set to all focal laws, the range is set so that all laws terminate at the selected depth entered.

Ø  Each mode has advantages for optimum use of window for data and how gates can be positioned.

47

Phased Array Using the OmniScan MX2 Part 2 - Data Selector Function Key Ø  In addition to dragging the data cursor on the touch screen or with a USB mouse,

the next easiest way to manipulate it is with the data selector function key and scroll knob. This is the preferred method.

Ø  A short stroke of the data selector function key displays and enables the angle window in the upper left hand corner of the MX2 display.

Ø  Expert use of the MX2 requires familiarity and fast interaction with the function keys and scroll knob.

Ø  Use of the function keys and scroll knob is the fastest easiest way to perform many functions and can be done at any time without changing the current menu. Practice with the function keys is highly recommended.

48

Intro to Phased Array Using the OmniScan MX2 Part 2– Data Source All Laws

Ø  When data source is set to all laws, the S-scan data cursor will dynamically track the highest amplitude signal in gate A, and the A-scan will display the sum of all focal laws in the group.

All laws Normal (One law)

Please send questions and comments to: PhasedArraySupport@olympusndt.com

Thank You!

www.olympus-ims.com