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Circ Inspection Manual

1. 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 1 USER MANUAL EMAT SYSTEM FOR GUIDED WAVE ULTRASONIC INSPECTIONS December 11 2002 Revision 4 0 Prepared For Professor Young Hwan Kim Sung Kyun Kwan University South Korea Prepared By Ron Alers Sonic Sensors of EMAT Ultrasonics Inc 170 Granada Drive San Luis Obispo CA 93401 PH 805 545 0675 FAX 805 545 0374 ron sonicsensors com Serial Number EMAT10K 11 PTB34 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 2 TABLE OF CONTENTS SPECIFICATIONS ies A RaR IAE se ER ua Oa ee BE UR on 3 Transmitter mesie A ko a o o 3 A A Pa e oo ee oo 3 SOFTWARE OMNEMAT A ri gat tu ev Pote OVA aE octan ad 4 EMAT SYSTEM CABLE DIAGRAM saint sea oo winston dev t o 5 SYSTEM DESCRIP HON les oxic ea ma bana u Vy een eared eT 6 BEOCH DIAGRAM ea vis Bact O B on R SA sku nun 7 Timing BAT PZ OLE VRS an a ewes G e E ova BN anno e usb 8 TONE BURST GENERATION TA Borrada A a a i 9 A D Card A A SS 11 GATE FUNGHON tlc esha cody see O ey A O O NE is 12 SCAN DES as ean spy aap ea aod A Ae 13 AMPLITUDE SCAN ASS A Ns a 14 Amplittide Scan Gate DER HOW reddit Didi Kikan ngk 15 FLAW DETECT SCAN poronienie rated Ran an An a 16 Flaw Detect Scar Gate Definition ta 17 STACKED A
2. ClockMHz 1 DutyCycle 1000 PercentDutyCycle 19 ScanTimerBased 1 EncoderBasedStart 0 0000 EncoderBasedStep 1 0000 Sonic Sensors EncoderBasedStart END TONEGEN START ATODCARD TypeID 22 Version 1 SampleRate ChannelMode BoardNumber BaseHz 3 TriggerSource TriggerExtCoupling TriggerExtGain TriggerSlope TriggerLevel TriggerDepth TriggerTimeout InvertStatus TriggerShouldTimeout TriggerOffset UnbusyTimeout UnbusyShouldTimeout END ATODCARD START SCAN TypeID 19 Version 1 START SIGNALSET Board 1 Channel 1 BufferOffset START GATE UsecStart UsecDuration Operation END GATE START GATE UsecStart UsecDuration Operation END GATE START GATE UsecStart UsecDuration 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc www sonicsensors com 26 Units 25 WO Rod k o 180 4096 96 64 100 30 00 10 00 2 00 3 00 86 00 10 00 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 27 Operation 0 END GATE START GATE UsecStart 34 20 UsecDuration 4 00 Operation 0 END GATE START AMPTIME2F DATA START DATA ItemStart 0 ItemDuration 4000 ItemFinish 4000 NumBitsPerltem 8 MaxBuffers 700 BiggestCapturedIndex 451 ChangeDatalndex 451 FirstBufferIndex 0 WrapAround true HasWrappedAround false END DATA AAmpMin 0 00 AAmp
3. TONE BURST GENERATION TAB Tone Gen A D Card Scan Triggering is Filters Freg KHz 11090 lt gt IV Pulse Timer Based Filter 1 Freq K Hz 1000 KI gt I Dual Frequency C Encoder Based Filter 2 Start Position 0 Filter 3 ra Pulse Hz 11 Jai gt eh an Tone Count 5 KISI Units Units Pulse m p fay o fa z A min Offset usec 0 Width usec 50 DT Gain 1 73 lt gt dd gt Sia Gain 2 J130 gt DT Ganzio ef gt Sig Gain2 4 0 lt f gt Analog 5 fo xol Analog 6 0 lt f Anao fo lt f gt Magneton fo lt j gt MaonetO fo lt j gt Figure 1 Tone Generation TAB pulser and receiver parameters are adjusted in this TAB PULSE Starts the system firing the transmitter and acquiring wave forms DUAL FREQUENCY Turns on the frequency toggle Alternating Tone Burst firing Freq 1 then Freq 2 then Freq 1 then Freq 2 etc Permits two acoustic tests to be performed simultaneously TIME BASED ENCODER BASED The check box defines if an internal clock generates the trigger or an external encoder generates the trigger ENCODER BASED gt A scan will ONLY proceed when an external encoder moves and supplies a trigger The encoder step size and units may be entered in these txt boxes Pulse Hz PRF Pulse Repetition Frequency Number of wave Acquisitions per cycle Cycles Number of Cycles in the tone burst DT DT Time is a time period the DT Gain is active per
4. 2 pairs of filters for each frequency 0 40dB of gain in the chassis with 60 dB of gain in the EMAT probe MBB Main Bang Blanking turns off the receiver during the Tone Burst and displays an attenuated view of the transmitter output Controllable from 0 255 usec 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 4 SOFTWARE OmnEMAT 4 3 FEATURES 1 2 3 Analog wave form display in real time System Set Up stored and retrieved with Configuration Files enabling previous set ups to be duplicated as easily as opening a file Single frequency or dual frequency independently viewed and set up with independent TAB controls Scan Types Included Amplitude Scan 2 Amplitudes and Two Arrival Times are plotted in real time Flaw Detect Scan One fixed amplitude gate and a floating amplitude gate which is centered over the largest signal in a specified range are plotted real time including the arrival time of the searched for peak Stacked A Scan display with 8 bit color and mouse cursor point identification Position Amplitude and Arrival Time are displayed for the point of the mouse cursor If the mouse is dragged from one point to another the differentials are displayed so the user can easily measure the change in arrival time between two waves or the change in amplitude or position of two waves This is a very powerf
5. Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 5 EMAT SYSTEM CABLE DIAGRAM Computer EMAD High Chassis Power Revr1 IO EMAT Pulser Receiver Scanner Controller 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 6 SYSTEM DESCRIPTION The EMAT Ultrasonic Testing System has been specifically designed to be a general purpose instrument utilizing the Electromagnetic Acoustic Transducer EMAT The EMAT provides a vast array of design possibilities and unmatched control over numerous acoustic modes EMATs can be designed with a fixed wavelength to provide additional acoustic control An EMAT can also be designed to be broad banded and excite waves based on the frequency driven The EMAT Pulser Receiver Chassis can drive any EMAT with in the specified frequency range Peak drive efficiency is achieved when the transmitter impedance is near 50 Ohms This EMAT Ultrasonic Inspection System is based on tone burst ultrasonics The tone bust is defined by the specification of a frequency and the number of cycles Transduction efficiency of a particular wave mode may be greatly enhanced by using many cycles in a driven tone burst to excite the specific mode Using a multi cycle tone burst helps isolate a specific wave mode by d
6. Inc Sonic Sensors www sonicsensors com 7 BLOCK DIAGRAM COMPUTER Pulser Receiver Chassis The system consists of a computer with a COM port and a high speed data acquisition card The computer communicates through a RS232 COM port to a microcontroller which operates all the routine functions of the pulser receiver chassis The microcontroller sends a tone bust to the transmitter which amplifies it to a very high power signal capable of driving the EMAT transmitter The small signals received by the EMAT receiver are amplified on board the EMAT and than sent to the pulser receiver chassis for preparation for digitization by the computer 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 8 Timing Diagram Magnet j On Magnet Off ee n E Trigger Tone Burst Sig Gain 1 RF Display Freq 1 Tone Burst Freq 2 DT Gain 2 RF Display TIMING DIAGRAM 1 Shows the sequence of events during a dual frequency pulsing cycle Note a Dual Frequency Scan takes twice as long to complete because there are two pulse cycles for each data point A single Frequency cycle provides a data point every pulse 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 9
7. KME gt Figure 2 A D Card Analog to Digital Conversion Card parameter TAB Time Gates are specified to perform various graphing functions in the assorted Scan Types The A D Card Tab defines all the parameters of the Analog to Digital Converter Card Sample Rate gt sets the digitization rate in Mega Samples per Second MS s Trigger Depth gt determines how many samples are taken each pulse 8000 is hard coded Trigger Level gt sets the level to trigger te acquisition process must be gt 128 GATE DEFINITIONS First Box Start of the Gate Second Box Duration of the Gate Third Box End of Gate either the duration or end of gate may be entered and the other will be calculated Each Scan Type has a unique number and style of Gates Shown in Fig 2 are the five gates needed for the Amplitude Scan There are two transit time gates and two Amplitude gates and the bottom gate is an optional ZERO REFERENCE Gate for the Transit Time Gates 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 12 GATE FUNCTION Amplitude Gates Amplitude gates are used to measure the size of the acoustic signal received In the case of tone burst ultrasonics there are numerous peaks in a tone burst which define the amplitude Instead of measuring the single highest peak the signal can be rectified and integrated to i
8. SCAN AS V A NN na 18 MOTION CONTRO dia vee en yan ke ubo TB ka st o o uu 20 DY Ste Pece Configuratii AAA A Bo eba A S Enis 21 Scanner Encoder Encoder Based Scanning ved an 21 Iicreasing Scan Pe en Bun kah 21 TETRENT S DU ar a 22 O O 23 Appendix A O O O EN GA NET ah NANGA 24 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 3 EMAT Pulser Receiver Chassis EMAD10K 11 PTB SPECIFICATIONS Transmitter g PON SD Frequency Range 100 KHz 9 99MHz Load Impedance 30 50 Ohms Tone Burst is defined by number of cycles and frequency Tone Burst Cycles from 1 to 255 with software duty cycle limitation to 0 1 PRF Pulse Repetition Frequency 1 Hz 1000Hz in 1 Hz increments software duty cycle limit to 0 01 duty cycle as calculated with the number of cycles in the tone burst Dual Frequency Mode The system can be operated in single frequency mode or dual frequency mode In two frequency mode two frequencies are definable with the same number of cycles in each tone burst The two tone bursts are generated alternatively switching from one to the other and synchronized with the hardware and software Receiver TP WNP Non linear gain control Two independent gain levels switched anywhere from 0 255 usec Dual Frequency Mode can provide a different filter for each frequency Four filters available or
9. TRUNCATED 63 23 281 60 04 52 33 277 55 64 53 18 2 82 54 38 52 68 2 84 56 57 END RESULTS DATA END AMPTIME2F DATA END SIGNALSET END SCAN END MODEL Gate3 Zcross2 19 76 19 72 19 69 19 69 19 72 20 15 20 19 20 21 0 00 80 00 36 02 0 00 80 00 19 68 60 false 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc www sonicsensors com 29
10. as successive wave forms have the same peaks and vallies which appear as red high or blue low with green as the baseline of zero amplitude Two styles of color tables are available to view the data Rectified and non rectified Sometimes the phase features of a wave form are not important and only amplitude is of interest Rectification of the wave essentially doubles the frequency of the peaks and high amplitudes become all red and low amplitudes are blue making the rainbow color spectrum concentrated from zero amplitude to full screen height The rectified color table offers twice the amplitude resolution of the non rectified color table because the color differences are concentrated over half the range Quantitative Analysis Tool The mouse pointer displays the amplitude position and arrival time when it is placed on the graph Two points can be compared by dragging the mouse pointer between two points The difference between the start point and end point will be displayed on the lower right hand side of the screen The display reads as follows A amplitude P position T arrival time dA change in amplitude dP change in position dT change in arrival time 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 14 AMPLITUDE SCAN Tone Gen 8 D Card Amp Time Counter Ampt 51 4677 Min J ol Ma 20 Keji Save up to e
11. attemps to trigger the acoustic system faster than 100 Hz a hardware limit will skip the pulse exceeding the 100 Hz period Each missed pulse is logged and displayed at the end of the scan as ERROR COUNTS The Error counter only counts up to 255 and can roll over if the scan is run excessively fast This should never occur because the operator should know the maximum scan speed If the encoder based scan travels further than it should the scan rate is probably missing points and counting errors Run the system at a conservative scan rate which matches the step size increment 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 21 System Specific Configuration Scanner Encoder Encoder Based Scanning The step size of the scanner is set on a DIP switch in the Pulser Receiver chassis The DIP switch is accessible by removing the bottom cover of the Pulser Receiver chassis The DIP switch is located in the rear near the fan Encoder Dip Switch Set at 5 step size of 0 134 inches pulse Maximum pulse repetition rate of computer 100 pulse second computer bus and processor dependent Error Counter Set at 100 Hz The computer speed limits the maximum pulse repetition rate The computer has been measured to process up to 100 measurements pulses per second A step size of 0 067 inches per pulse at 100 Hz PRF permits th
12. Detect Scan Save Scan Open Scan Clear Scan EBS Peak AveAmp 4 76 Min o lt gt Max 80 lt gt Save upto 60 pulses of data EE Peak Usec 3232 Min fo KJS Ma mo es I Save after 60 pulses i p Span 100 lt gt Center 60 lt gt Make Peak Gate s Width Same as DT Gate Width Ha DT AveAmp 5560 Min j0 lt gt Max eo lt p gt lb micro seconds Peak Ave Amplitude Counter 0 Noise Threshold 10 Peak Usec peate A Parma a wi A 1 A Waa MMU A Mh Pl A 7 ites nti MA by E NGN a ayy md dian DT Ave Amplitude Figure 5 Flaw Detect Scan Displays three features The BLUE marks show the arrival time of the PEAK amplitude in the search gate The RED line in the upper graph shows the integrated amplitude of the PEAK signal in the search gate The displayed scan shows echos from five cracks at different distances The first crack on the left was the furthest away with the echo arriving at 100 usec The last crack was the closest arriving at 50 usec 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 17 Flaw Detect Scan Gate Definition Figure 6 A D Card Set Up for Flaw Detect Scan There are only two gates to set for the Flaw Detect Scan The DT Amp gate captures the reference Direct Transmission signal The Peak Find gate is large and de
13. H 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 15 Amplitude Scan Gate Definition ToneGen A D Card Ame Time Freq 1 Ampl jo jeo 2s oo Sample Rate 25 Trigger Depth 8000 Unbusy Timeout msec 100 ZCross1 23 fe 25 00 T Dual Channel Capture Trigger Level 200 IM UnBusy Should Timeout Amp2 39 e 00 47 00 Trigger Timeout msec 182 T Trigger Falling Edge ZCross2 42 E 44 00 IV Trigger Should Timeout I Invert Signal 5 2 00 2 50 Offset usec 0 Width usec feo gt Figure 4 Amplitude Scan A D Card Set Up Shown are two different wave packets one at 20 usec and the other at 55 usec Each wave packet has two gates defined an Amplitude and a Zero Crossing gate labeled Amp1 Z Cross1 Amp2 Z Cross2 respectively and colored as noted Amp1 BLACK Integrated Amplitude of Top Graph 1 Z Cross2 YELLOW Zero Crossing in the Top Graph 1 Amp2 RED Integrated Amplitude of Bottom Graph 2 Z Cross2 BLUE Zero Crossing in the Bottom Graph 2 Zero Ref GREEN Bottom Gate with blank label Use in Tone Burst as a reference to measure the transit times from This increases resolution by removing the digitization error from the start of acquisition 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 16 FLAW DETECT SCAN Tone Gen 4 D Card Flaw
14. M300 1520 EMAT 0 M260 1520 EMAT 2 M200 1520 EMAT 2 M180 1515 EMAT 0 M160 1520 EMAT 0 2020CART Xmtr Transmitter cart with 2 x2 magnet 2 2020CART Rovr Receiver cart with 2 x2 magnet 2 F2020CART Foil Wear Surface 6 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 24 Appendix Sample Data File 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 25 Sample Data File of a DUAL FREQUENCY SCAN as saved by SAVE TO TEXT These Text files are designed to be read by a spread sheet program FORMAT 1 All configuration values are stored frequency gates etc 2 Results of Gates Amplitude or Zero Crossing value 3 RF wave form if selected CAUTION these files get VERY large VERY quickly 4 DUAL FREQUENCY scans repeat 1 2 and 3 for the second frequency Single Frequency scans only include 1 2 and 3 once Pitting M160 SO and S1 START MODEL TypeID 55 Version 1 START TONEGEN TypeID 21 Version 1 FrequencyMultiplier 3 Frequency1 550 Frequency2 700 RepeatRate 21 ToneCount 5 MBBUsec 14 DTUsec 40 AnalogOutl 87 AnalogOut2 125 AnalogOut3 65 AnalogOut4 100 AnalogOut5 0 AnalogOut6 0 AnalogOut7 0 AnalogOut8 222 MagnetOn 0 MagnetOff 31 OutPort 0 OutPort2 0 PulseMode 1 Enable 0 Filter 0
15. Max 80 00 AZSpan 30 00 AZCenter 36 02 BAmpMin 0 00 BAmpMax 80 00 BZSpan 30 00 BZCenter 19 68 SaveSeconds 60 AutoSave false START RESULTS DATA Gate Gatel Gate2 Gate3 Ampl Zcrossl Amp2 Zcross2 64 57 3 24 63 04 36 07 66 89 3 24 62 82 36 06 65 37 3 24 63 24 36 06 kkkkkkk TRUNCATED RREERERE 64 45 3 28 61 91 36 12 64 89 3 24 63 81 36 06 65 51 3 28 61 52 36 09 Sonic Sensors END RESULTS DATA END AMPTIME2F DATA END SIGNALSET START SIGNALSET Board 1 Channel 1 BufferOffset START GATE UsecStart UsecDuration Operation END GATE START GATE UsecStart UsecDuration Operation END GATE START GATE UsecStart UsecDuration Operation END GATE START GATE UsecStart UsecDuration Operation END GATE START AMPTIME2F DATA START DATA ItemStart ItemDuration ItemFinish NumBitsPerltem MaxBuffers BiggestCapturedIndex ChangeDatalndex FirstBufferIndex WrapAround HasWrappedAround 16 00 8 00 1 50 3 00 45 00 8 00 18 50 3 00 4000 4000 700 451 451 true false 170 Granada Drive Suite D San Luis Obispo PH 805 545 0675 California 93401 FAX 805 545 0374 of EMAT Ultrasonics Inc www sonicsensors com 28 Sonic Sensors END DATA AAmpMin AAmpMax AZSpan 30 00 AZCenter BAmpMin BAmpMax BZSpan 30 00 BZCenter SaveSeconds AutoSave START RESULTS DATA Gate Gatel Gate2 Ampl Zcrossl Amp2 63 71 2 84 60 11 62 89 2 81 60 54 62 35 2 78 61 33 62 05 2 78 60 27
16. able may be changed in the color table Pull Down menu in the top of the screen Mouse Pointer Scale The values associated with the mouse pointer position is displayed continuously while the mouse is over the graph Differential measurements may be made by dragging the mouse from one point to another The change of dP position dT time and dA amplitude are displayed in the lower right after a mouse drag is performed 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 20 MOTION CONTROL Control of the scanner may be performed in software using the lt Motion Control Tool bar gt located in the menu in the top of the screen The software control permits the scanner to be started and stopped automatically during an Encoder Based Scan This is a convenient feature for automated scanning The tool bar may be placed anywhere on the desk top by dragging it with the mouse An automated scan will run in the direction last set in the motion control tool bar The scan velocity is determined by the voltage level manually set on the Motion Control Power Supply Motion Reverse Foward Close a Acoustic measurements are triggered by the encoder during encoder based scanning The scan can be jerky or intermittent and the encoder will smooth ou the data aquision for precise lacations If the scanner moves too fast and
17. computer can find the peak anywhere in the first half of the gate 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 13 SCAN TYPES There are five scan types available in OmnEMAT These scan types have different methods of graphing to enhance certain acoustic features These scan types are described individually below 1 Amplitude Scan Plots the integrated amplitude of two separate gates and the transit times of two additional gates Typically used to plot the amplitude and arrival time of two different wave packets 2 Flaw Detect Scan Plots the integrated amplitude of a fixed gate and searches a larger gate for the greatest amplitude above a threshold The peak amplitude in the large gate is integrated around by a fixed time period and the arrival time of the peak is displayed The integration time around the peak may be set to be the same as the initial fixed integrated amplitude gate or the integration period may be typed in 3 Stacked A Scan creates a colored 3 dimensional view of an acoustic signal The amplitude fo the entire wave form is displayed as a function of color The horizontal axis represents the arrival time of the wave Successive acoustic acquisitions are displayed adjacent to each other forming the vertical axis acquisition number or if scanning the scan position THe phase features show up as vertical lines
18. e scanner to be run at 6 7 inches per second or 33 feet per minute Exceeding this rate will create missed data points which will be displayed on the Amp Time Scan as errors The error count only goes up to 255 errors per scan This assumes the operator will minimize errors by keeping the scan rate below these limits ENCODER RESOLTION 0 008 inches per pulse lt Switch Inches pulse 0 1 0 0084 2 2 0 0167 4 3 0 0335 8 4 0 067 16 5 0 134 32 6 0 268 64 7 0 536 128 8 1 072 256 9 2 144 Increasing Scan Speed If higher speed scans are desired simply increase the step size to not exceed the PRF limit of 100 Hz The table above shows the step sizes resulting from the DIP switch setting For example DIP switch 3 would provide 0 134 inch steps enabling a scan speed one foot per second The motor drives a chain with a 3 1 speed reduction For academic research use torgue was considered more important than speed The easiest way to increase the speed is by changing the drive sprocket and possibly lengthening the chain 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 22 TETHER PIN OUT Tether has a HIROSE 12 pin connector on the Pulser Receiver Chassis to house system IO The Scanner has a Burndy TrimTrio 16 19 connector for a single connector quick release of all connections The
19. efining the frequency over a narrow band The more cycles in the tone burst the more precise or pure the wave mode may be In the case of dispersive modes when the group velocity is different than the phase velocity The phase velocity may be easily measured with this instrument by using the transit time feature built into the software The group velocity is more difficult to measure because a feature defined by the envelope of the received tone burst must be used Defining an envelope feature in a dispersive signal can be a difficult task The Amplitude of a received wave packet is most accurately determined by integrating the amplitudes of the entire wave packet These three basic measurements account for virtually all the useful information in a tone burst Once a tone burst is excited it may be received a period of time later and filtered or rectified with velocity or amplitude information extracted Included are many Scan Types enabling a multitude of measurements to be made and displayed in real time The results may be saved in binary form or ASCII text for post processing in a spread sheet or other program Raw RF wave forms may also be saved in either binary or text format Saving an RF signal in text can create horrendously large files which exceed the size limit for MS EXCEL necessitating other analysis tools to be used 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics
20. fines the period of time to search through to locate the highest peak signal The integrated amplitude around the peak is performed for every acquired signal 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 18 STACKED A SCAN Tone Gen A D Card Stacked A Scan Pulses 3 Beset Save Scan Open Scan 0 120 240 360 480 600 35 42 43 56 Usec P 0 00 T 40 36 A 123 N A Figure 7 Stacked A Scan display of a scan past two large cracks and a smaller crack in between 600 acquisitions are displayed on the screen from top to bottom with the gated time slice in the horizontal axis The default color table displays a rainbow over the range of 0 255 showing peaks as red and valleys as blue 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 19 Tone Gen A D Card Stacked A Scan Start Scan Reset Save Scan a Scan Pulses 0 120 240 360 480 600 35 42 43 56 Usec P 4 00 T 39 56 A 131 dP 1 00 dT 0 44 d 229 Figure 8 The rectified color table shows a rainbow of colors from blue to red over the range of 128 center screen no signal amplitude to 0 and conversely to 255 This rectification shows twice the frequency as the normal display The color t
21. mits lower gain during the large Direct Transmission Signal FOR FREQUENCY 1 ONLY See Magnet Off Tone Amp Transmitter Output Level from 0 255 DT Gainl adjusts the gain from 0 255 for the period up to the DT Time Sig Gain1 Gain level from 0 255 for time after DT Time 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 10 DT Gain2 DT Gain for Freguency 2 Sig Gain2 Signal Gain for Freguency 2 Magnet Off For use in Dual Freguency Mode only This time value controls the DT time of FREO 2 only independently of DT Time for FREO 1 This option is selected by the jumper on the analog board JP1 If the same DT Time is desired for both FREO 1 and FREO 2 pull open JP1 and insert short JP2 These jumpers are surface mount devices located near IDC1 one of the ribbon connectors 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors a E A 11 A D Card TAB Tone Gen A D Card Ame Time Freq 1 Ampl E jeo 28 00 Sample Rate 25 Trigger Depth 8000 Unbusy Timeout msec 100 ZCross1 fe 25 00 I Dual Channel Capture Trigger Level 200 IV UnBusy Should Timeout Amp2 e 0o Trigger Timeout msec 182 T Trigger Falling Edge ZCross2 W Trigger Should Timeout T Invert Signal Offset usec 0 Width usec 50
22. ncorporate the amplitude of the entire tone burst An amplitude gate rectifies the signal bounded by the gate and sums all amplitudes values with in the gate To normalize the sum is divided by the width of the gate providing essentially a Fill Factor of the gate This is an effective way to measure amplitude of a tone burst and benefit by some noise immunity Zcross or Time Gate The arrival time of a signal can be precisely measured by the point where the RF signal passes through zero We call this point a zero crossing or Zcross for short Measuring the zcross is a measure of the phase velocity of a signal Non dispersive modes have identical phase and group velocity Precision time measurements are made by interpolating the zero crossing between data points on a negative going slope The Zero Crossing is located by finding the largest peak in the first left half of the gate and then moving to the right until the signal passes through zero The exact point of crossing is calculated by interpolation using data points on both sides of the zero TIPS When setting up the Zcross gate be anticipate which direction the zero crossing will move during the scan If the velocity will only speed up during the scan place the left edge of the Zcross gate just to the right of the earlier peak This way the same peak will be chosen during the Zcross calculation If there is only one predominate peak in the wave packet a very large gate may be used and the
23. o pulses of data a ane ao I Save after 60 pulses Clear Scan y za GREE Au T si ae Oupot Amp 435970 Mn 0 Kici Max 80 sf Save Scan OpenScan 9 Zcross2 417693 Span l gt Center 47 3400 lt gt ZCross usec Amplitude 8 My yan da i q put NANY AAN Pia N Figure 3 Amplitude Scan Amplitude and Arrival Time of a wave packet is displayed with a Red Amplitude Line and a Blue Arrival Time Line An additional graph of the same features are displayed on the lower graph This graph shows the amplitude of the two received signals stayed constand but the phase velocity changed as the distance between the transducers changed The scale of each graph is defined in the text boxes in the upper right The amplitude graph requires a MINimum and MAXimum value The arrival time graph is typically a high resolution scale to facilitate this a full scale SPAN is required and a CENTER button is provided to center the time scale at the defined resolution around the last data point taken LENGTH OF SCAN is determined by entering the number of pulses or data points to save in a scan If the Save After Pulses is NOT checked the scan will run continuously and wrap around over the previous data Timer Based scanning will use the PRF to determine the number of seconds in a scan Scan Length pulses Scan Duration seconds x PRF pulses per second 170 Granada Drive Suite D San Luis Obispo California 93401 P
24. se connectors were wired with respect to the following table Buckeye Box both ends Female Scanner 12pin TrimTrio 18pin RG174 AAA WHITE BROWN WHITE 7 Description RCV Sig RCV gnd MOTOR MOTOR 5V ENCODER SIG A ENCODER GND PRE AMP SHIELD GND CHASSIS GND ENCODER 8V PRE AMP 8V PRE AMP Pink RG174 ASA a AM A Le E je Z1Z z 12 NC R68 me PTS Re58 TNC ________l csb__ XMTSHIELD CONNECTOR PART VENDOR PHONE HIROSE 12pin CABLE PLUG RM 15TPD 12P DIGI KEY 1 800 344 4539 TRIM TRIO Plug cable G6F19 195NE CTI 1 800 458 5646 TRIM TRIO Pins RM24M 9D28 CTI 1 800 458 5646 TRIM TRIO Receptacle Chassis GOF16 19PNE CTI 1 800 458 5648 TRIM TRIO Socket RC24M 9D28 CTI 1 800 458 5649 170 Granada Drive Suite D San Luis Obispo California 93401 PH 805 545 0675 FAX 805 545 0374 of EMAT Ultrasonics Inc Sonic Sensors www sonicsensors com 23 TETHER The 100 foot tether with RG58 50 Ohm cable was tuned to provide efficient power transfer to the Transmitter EMAT If other transmitter cables are used less than optimal power will reach the transmitter and smaller signals will be realized NOTICE If shorter tethers are used with this system the transmitter power will be less than optimal Best performance may only be achieved with the 100 tether supplied Spare Parts EMAT Description Quantity Part Number Original Order M440 2020 EMAT 2 M340 2020 EMAT 2
25. ul analytical tool It also works well for thickness gauging applications All scans can be saved in the following manner Save to ASCII Text for graphing in a spread sheet or other analysis package Save RF to ASCII text which saves the ENTIRE RF wave forms taken during a scan These files may be many MegaBytes in size Save RF in binary format so the scan can be reloaded in OmnEMAT 4 and scales changes or thresholds modified Useful as a post processing tool Timer based scans or Encoder based scans can be set up Timer based takes data at a designated time interval from 1 Hz to 100 Hz The ultimate speed is determined by the speed of the computer and the data acquisition time Encoder Based Scanning includes a separate encoder which triggers the system to fire Even if the scanner is rough and jerky the scan will be smooth and capable of length measurements Caution must be exercised to not scan too fast and exceed the duty cycle of the gated amplifier An adjustable hardware safety is included to protect the hardware where as excessive scan speed will only result in lost data Supports all ISA 8 bit GAGE A D cards GAGE Compu Scope 225 dual channel A D card capable of 50 MS sec of 8 bit data was used Available Digitization Rates 1 2 5 10 25 50 MS s Mega Samples sec 8000 point data transfer block per acquisition Sample Rate MS sec Data Acquisition Depth usec 1 8 000 5 4 000 10 800 25 320 50 160 170 Granada

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