User`s Manual - SaluTron Messtechnik GmbH
Contents
1. 19 Appendix A Sound Velocities Material Sound Velocity in us m s Aluminum 0 250 6340 6400 Steel common 0 233 5920 Steel stainless 0 226 5740 Brass 0 173 4399 Copper 0 186 4720 Iron 0 233 5930 Cast Iron 0 173 0 229 4400 5820 Lead 0 094 2400 Nylon 0 105 2680 Silver 0 142 3607 Gold 0 128 3251 Zinc 0 164 4170 Titanium 0 236 5990 Tin 0 117 2960 Epoxy resin 0 100 2540 Ice 0 157 3988 Nickel 0 222 5639 Plexiglass 0 106 2692 Polystyrene 0 092 2337 Porcelain 0 230 5842 PVC 0 094 2388 Quartz glass 0 222 5639 Rubber vulcanized 0 091 2311 Teflon 0 056 1422 Water 0 058 1473 20 Appendix B Applications Notes Measuring pipe and tubing When measuring a piece of pipe to determine the thickness of the pipe wall orientation of the transducers is important If the diameter of the pipe is larger than approximately 4 inches measurements should be made with the transducer oriented so that the gap in the wearface is perpendicular at right angle to the long axis of the pipe For smaller pipe diameters two measurements should be performed one with the wearface gap perpendicular another with the gap parallel to the long axis of the pipe The smaller of the two displayed values should then be taken as the thickness at that point Perpendicular Parallel Measuring hot surfaces The velocity of sound through a substance is dependant up2. Different types of material however will require the use of different transducers Choosing the correct transducer for a job is critical to being able to easily perform accurate and reliable measurement The following paragraphs highlight the important properties of transducers which should be considered when selecting a transducer for a specific job Generally speaking the best transducer for a job is one that sends sufficient ultrasonic energy into the material being measured such that a strong stable echo is received by the gauge Several factors affect the strength of ultrasound as it travels These are outlined below Initial Signal Strength The stronger a signal is to begin with the stronger its return echo will be Initial signal strength is largely a factor of the size of the ultrasound emitter in the transducer A large emitting area will send more energy into the material being measured than a small emitting area Thus a so called 1 2 inch transducer will emit a stronger signal than a 1 4 inch transducer Absorption and Scattering As ultrasound travels through any material it is partly absorbed If the material through which the sound travels has any grain structure the sound waves will experience scattering Both of these effects reduce the strength of the waves and thus the gauge s ability to detect the returning echo Higher frequency ultrasound is absorbed and scattered more than ultrasound of a lower frequency
3. multiple times to activate the Transducer model tab Use the key and the e key to switch to the desired transducer model Press the key to exit You can also change the transducer model set by menu operation Please refer to chapter 5 for the help of menu operation 4 3 Probe Zero 1 The key is used to zero the instrument in much the same way that a mechanical micrometer is zeroed If the gauge is not zeroed correctly all the measurements that the gauge makes may be in error by some fixed value When the instrument is zeroed this fixed error value is measured and automatically corrected for all subsequent measurements The instrument may be zeroed by performing the following procedure 2 Make sure the instrument is on and the Two Point calibration function is OFF The Probe Zero function is disabled in Two Point calibration mode 3 Plug the transducer into the instrument Make sure that the connectors are fully engaged Check that the wearface of the transducer is clean and free of any debris 4 Change the model of the transducer set in the instrument to the model currently using 5 Apply a single droplet of ultrasonic couplant to the face of the metal probe disc 10 6 Press the transducer against the probe disc making sure that the transducer sits flat against the surface While the transducer is firmly coupled to the probe disc press on the keypad The instrument will display ZER on the
4. of current operation FIL File selection MEM Memory data viewing PRB Transducer set VEL Change velocity CAL Velocity calibration DPC Dual Point Calibration state ZER Probe zero state SCA Indicate that current thickness measurement mode is scan mode and not single point mode File Name show current file name Record No Count Indicate current record number while this item is highlighted or total record counts while it is not highlighted Transducer Model Current transducer model setting in the instrument Sound Velocity Current sound velocity setting Thickness Reading Display present single time measured value T means exceeding upper measuring limit J means lower than bottom measuring limit Units Label When the mm symbol is on the instrument is displaying the thickness value in millimeters and the sound velocity value in m s When the in symbol is on the instrument is displaying the thickness value in inches and the sound velocity value in inch us 2 4 Keypad Definitions Turn the instrument Exit from current Data Save or Data Delete on and off selection Turn on off the EL Enter backlight Probe Zero Plus or scroll up ZERO operation iz Switch selection Minus or scroll among items down E 3 Preparation 3 1 Transducer Selection 1 The gauge is inherently capable of performing measurements on a wide range of materials from various metals to glass and plastics
5. operating hint area while it is calculating its zero point After the ZER disappears remove the transducer from the probe disc At this point the instrument has successfully calculated its internal error factor and will compensate for this value in any subsequent measurements When performing a probe zero the instrument will always use the sound velocity value of the built in probe disc even if some other velocity value has been entered for making actual measurements Though the instrument will remember the last probe zero performed it is generally a good idea to perform a probe zero whenever the gauge is turned on as well as any time a different transducer is used This will ensure that the instrument is always correctly zeroed 10 Press while in probe zero state will stop current probe zero operation 4 4 Sound Velocity 1 In order for the gauge to make accurate measurements it must be set to the correct sound velocity for the material being measured Different types of material have different inherent sound velocities If the gauge is not set to the correct sound velocity all of the measurements the gauge makes will be erroneous by some fixed percentage The One Point calibration is the simplest and most commonly used calibration procedure optimizing linearity over large ranges The Two point calibration allows for greater accuracy over small ranges by calculating the probe zero and velocity Note One and Two
6. use on Thickness Gauge the PC Communication a a Cable 1 5 Operating Conditions Operating Temperature 20 C 60 C Storage Temperature 30 C 70 C Relative Humidity lt 90 The surrounding environment should avoid of vibration strong magnetic field corrosive medium and heavy dust 2 Structure Feature 2 1 Instrument Appearance UTG Alpha vurisone 1 Main Body 2 Transducer 1 n x LI F L 2 2 2 Parts of the Main Body A Be SaluTron L 7 UTG Alpha Se 6 9 THICKNESS GAUGE 10 2 1 Plug in the sducer 2 OJ Power On Off 3 H e 4 E Pi 5 s 6 la Save 7 El Exit SaluTron 7 ee 3 i L C 4 1 Communication Socket 2 Aluminum Case 3 Belt Hole 4 Battery Cover 5 Keypad 6 LCD Display 7 Socket of Transducer no polarity 8 Probe zero disc 9 Aluminum Case 10 Label 2 3 Measurement Screen Thickness Operating Hint Reading Battery Info Coupling Status Sound Velocity Record No count Transducer Model Battery Information Display the information of the rest capacity of the battery Coupling Status Indicate the coupling status While the gauge is taking a measurement the coupling status should be on If it is not on the gauge is having difficulty achieving a stable measurement and the thickness value displayed will most likely be erroneous Operating Hint Show hints
7. PC will appear on the operating hint area of the main measurement screen Press to start the calibration procedure The string NO1 will appear on the operating hint area indicating measuring the first point Apply couplant to the sample piece Press the transducer against the sample piece at the first second calibration point making sure that the transducer sits flat against the surface of the sample The display should show some probably incorrect thickness value and the coupling status indicator should appear Having achieved a stable reading remove the transducer If the displayed thickness changes from the value shown while the transducer was coupled repeat step 4 Use the Le key and the e key to adjust the displayed thickness up or down until it matches the thickness of the sample piece Press the key to confirm The hint will changes to NO2 indicating measuring the second calibration point Repeat steps 3 through 7 The hint will change back to DPC 10 The gauge is now ready to perform measurements within this range 4 7 Scan mode 1 While the gauge excels at making single point measurements it is sometimes desirable to examine a larger region searching for the thinnest point The gauge includes a feature called Scan Mode which allows it to do just that 2 In normal operation the gauge performs and displays four measurements every second which is quite adequate for single measurements 3 In
8. Scan Mode however the gauge performs ten measurements every second and displays the readings while scanning While the transducer is in contact with the material being measured the gauge is keeping track of the lowest measurement it finds 4 The transducer may be scrubbed across a surface and any brief interruptions in the signal will be ignored When the transducer loses contact with the surface for more than two seconds the gauge will display the smallest measurement it found 5 When the transducer is removed from the material being scanned the gauge will display the smallest measurement it found 6 Onthe Test Set gt Work Mode menu item press l to toggle between single point mode and scan mode 13 4 8 Limit Set The Limit Set feature of the gauge allows the user to set an audible and visual parameter when taking measurements If a measurement is beyond the limit range set by the user the beeper will sound if enabled This improves the speed and efficiency of the inspection process by eliminating constant viewing of the actual reading displayed The following section outline how to enable and set up this feature 1 Onthe Test Set gt Tolerance Limit menu item press the key to activate the limit set screen 2 Use the key the 2 key and the Le key to change the bottom limit and the upper limit value to the desired values 8 Press the key to confirm the change and return to the previous screen or press the key
9. UTG Alpha Ultrasonic Thickness Gauge User s Manual i caNIK i SaluTror GmbH Contents 1 Overview 1 1 Product Specifications 1 2 Main Functions 1 3 Measuring Principle 1 4 Configuration 1 5 Operating Conditions 2 Structure Feature 2 1 Instrument Appearance 2 2 Parts of the Main Body 2 3 Measurement Screen 2 4 Keypad Definitions 3 Preparation 3 1 Transducer Selection 3 2 Condition and Preparation of Surfaces 4 Operation 4 1 Power On Off 4 2 Transducer Set 4 3 Probe Zero 4 4 Sound Velocity 4 4 1 Calibration to a known thickness 4 4 2 Calibration to a known velocity 4 5 Making Measurements 4 6 Two Point Calibration 4 7 Scan mode 4 8 Limit Set 4 9 Resolution 4 10 Unit Scale 4 11 Memory Management 4 12 Data Printing 4 13 System Set 4 14 System information 4 15 EL Backlight 4 16 Battery Information 4 17 Auto Power Off 4 18 System Reset 4 19 Connecting to a Computer 5 Menu Operation 5 1 Enter the Main Menu 5 2 Enter the Sub menu 5 3 Change the Parameter 5 4 Numeric Digit Input 5 5 Save and Exit 5 6 Cancel and Exit 6 Servicing OO O 090 00 UU P P P R Z e bes s656 H H rol ol E PHP PP PP PP ar Tone ao ees EGER R bbbbbbi CO o b 7 Transport and Storage Appendix A Sound Velocities Appendix B Applications Notes B 1 Overview The model UTG Alpha is a digital ultrasonic thickness gauge Based on the same operating pr
10. While it may seem that using a lower frequency transducer might be better in every instance low frequencies are less directional than high frequencies Thus a higher frequency transducer would be a better choice for detecting the exact location of small pits or flaws in the material being measured Geometry of the transducer The physical constraints of the measuring environment sometimes determine a transducer s suitability for a given job Some transducers may simply be too large to be used in tightly confined areas Also the surface area available for contacting with the transducer may be limited requiring the use of a transducer with a small wearface Measuring on a curved surface such as an engine cylinder wall may require the use of a transducer with a matching curved wearface Temperature of the material When it is necessary to measure on surfaces that are exceedingly hot high temperature transducers must be used These transducers are built using special materials and techniques that allow them to withstand high temperatures without damage Additionally care must be taken when performing a Probe Zero or Calibration to Known Thickness with a high temperature transducer Selection of the proper transducer is often a matter of tradeoffs between various characteristics It may be necessary to experiment with a variety of transducers in order to find one that works well for a given job The transducer is the business end
11. d glass on light the beam becomes diffused and scattered in all directions 3 In addition to posing obstacles to measurement rough surfaces contribute to excessive wear of the transducer particularly in situations where the transducer is scrubbed along the surface Transducers should be inspected on a regular basis for signs of uneven wear of the wearface If the wearface is worn on one side more than another the sound beam penetrating the test material may no longer be perpendicular to the material surface In this case it will be difficult to exactly locate tiny irregularities in the material being measured as the focus of the sound beam no longer lies directly beneath the transducer 4 Operation 4 1 Power On Off The instrument is turned on by pressing the key When the gauge is initially turned on the model type the manufacture information and the serial number will be displayed prior to entering into the main measurement screen It is turned off by pressing the key when it is on The tool has a special memory that retains all of its settings even when the power is off 4 2 Transducer Set The model of the transducer should be pre set to the instrument before measuring operation This enables the user to select the transducer type among supported transducers according to frequency and diameter depending on application requirements Use the following steps to select your transducer model On the measurement screen press the key
12. d in the memory after confirmation 4 12 Data Printing Before printing please insert one connection plug of the print cable Optional parts into the socket on the up left of the main body and insert the other plug into the communication socket of the mini printer 4 12 1 Print Current File Enter thel Print function menu screen and highlight the Print Current menu item then press the key This operation will send all the data in current file to the mini printer via RS232 port and print them out 4 12 2 Print Selected File Enter the Print function menu screen and highlight the Print Memory menu item then press the lE key After specifying the start file name and the end file name the gauge will send all the data in the files specified to print out 4 12 3 Print All Memory Enter thel Print function menu screen and highlight the Print All Mem menu item then press the key This operation will send all the memory data to the mini printer and print them out 4 13 System Set From the main menu screen press onthe System Set menu item and enter its submenu When Auto Save Jis set to lt On gt could store the measured data automatically to current file after measurement 15 When Key Sound issetto On the buzzer would make a short hoot while press the key each time When Warn Sound is set to On if the measured value exceeds the tolerance limit the buzzer would make a long hoot LCD Brightness Set Press i on the Syste
13. easuring Range Lower limit Description MHz mm N02 2 5 14 3 0mm 300 0mm in Steel 20mm for thick highly 40mm in Gray Cast Iron HT200 attenuating or highly scattering materials N05 5 10 1 2mm 230 0mm In Steel 20mmx3 0mm Normal Measurement NO5 5 10 1 2mm 230 0mm In Steel 20mmx3 0mm Normal 90 Measurement N07 7 6 0 75mm 80 0mm P15mmx2 0mm For thin pipe wall or small curvature in Steel pige wall measurement HT5 5 14 3 200mm In Steel 30mm For high temperature lower than 300 C measurement 3 2 Condition and Preparation of Surfaces 1 In any ultrasonic measurement scenario the shape and roughness of the test surface are of paramount importance Rough uneven surfaces may limit the penetration of ultrasound through the material and result in unstable and therefore unreliable measurements The surface being measured should be clean and free of any small particulate matter rust or scale The presence of such obstructions will prevent the transducer from seating properly against the surface Often a wire brush or scraper will be helpful in cleaning surfaces In more extreme cases rotary sanders or grinding wheels may be used though care must be taken to prevent surface gouging which will inhibit proper transducer coupling 2 Extremely rough surfaces such as the pebble like finish of some cast iron will prove most difficult to measure These kinds of surfaces act on the sound beam like froste
14. inciples as SONAR the UTG Alpha is capable of measuring the thickness of various materials with accuracy as high as 0 01 millimeters or 0 001inches It is suitable for a variety of metallic and non metallic materials 1 1 Product Specifications Display 128x64 dot matrix LCD with EL backlight Measuring Range 0 75 300 mm in Steel Sound Velocity Range 1000 9999 m s Resolution 0 1mm 0 01mm selectable Accuracy 0 5 Thickness 0 04 mm Units Metric English unit selectable Four measurements readings per second for single point measurement and ten per second for Scan Mode Memory for 20 files up to 99 values for each file of stored values Upper and lower limit can be pre set It will alarm automatically when the result value exceeding the limit Power Supply Two AA size 1 5 volt alkaline batteries 100 hours typical operating time EL backlight off Communication RS232 serial port Case Extruded aluminum body suitable for use under poor working conditions Outline dimensions 132mm X 76 2 mm Weight 345g 1 2 Main Functions 1 Capable of performing measurements on a wide range of material including metals plastic ceramics composites epoxies glass and other ultrasonic wave well conductive materials 2 Four transducer models are available for special application including for coarse grain material and high temperature applications 3 Probe Zero function Sound Velocity Calibration function 4 Two Poi
15. lues according the record number from the memory and display them on the Thickness Reading area of the screen simultaneously If you want to delete the displaying record data from the memory just press the key The other way to view the stored record is by menu operations On the Memory Manager gt View Mem Data menu press the key to activate the memory viewing screen 14 FOO 05 5 At most eight files including the file name the F01 99 99 record counts and the ratio used of the file F02 00 0 can be showed on one screen F03 00 0 Use the VE key to scroll up down FO4 00 04 i F05 00 0 Press J to exit browsing Press to see F06 00 0 details of that file l FO7 00 0 Press or to move the cursor to the dt a Be line which you want to see details Press E010 00 0 to see details of that file F011 00 0 F012 00 0 F013 00 0 l F014 00 0 4 00 5 01 6 01 The left screen displays the total five record 7 00 8 01 data in the file FOO 4 11 3 Clearing selected files Enter the Memory Management menu screen and highlight the Delete by File menu item Then press the key This function provides the user with the ability to delete the selected data files previously saved in memory 4 11 4 Clearing all the files Enter the Memory Management menu screen and highlight the Delete All Data menu item Then press the key This operation will delete all the measurement data store
16. ly way to reliably measure such materials is by performing a calibration procedure on a sample piece of known thickness Ideally this sample material should be a part of the same piece being measured or at least from the same lamination batch By calibrating to each test piece individually the effects of variation of sound velocity will be minimized An additional important consideration when measuring laminates is that any included air gaps or pockets will cause an early reflection of the ultrasound beam This effect will be noticed as a sudden decrease in thickness in an otherwise regular surface While this may impede accurate measurement of total material thickness it does provide the user with positive indication of air gaps in the laminate 21 Suitability of materials Ultrasonic thickness measurements rely on passing a sound wave through the material being measured Not all materials are good at transmitting sound Ultrasonic thickness measurement is practical in a wide variety of materials including metals plastics and glass Materials that are difficult include some cast materials concrete wood fiberglass and some rubber Couplants All ultrasonic applications require some medium to couple the sound from the transducer to the test piece Typically a high viscosity liquid is used as the medium The sound used in ultrasonic thickness measurement does not travel through air efficiently A wide variety of couplant materials may be u
17. m Set gt LCD Brightness menu item to enter the LCD brightness set screen On the screen press 2 to enhance the brightness or press Le to weaken the brightness Press to confirm the modifying or press to cancel the modifying 4 14 System information This System information function will display the information about the main body and the firmware The version would change with the firmware 4 15 EL Backlight With the background light it is convenient to work in the dark condition Press key to switch on or switch off the background light at any moment as you need after power on Since the EL light will consume much power turn on it only when necessary 4 16 Battery Information Two AA size alkaline batteries are needed as the power source After several hours usage of the preset batteries the battery symbol on the screen will be shown as d S The more of dark part indicates the more close to fill When the battery capacity runs out the battery symbol will be shown as T land will begin to flash When this occurs the batteries should be replaced Refer to the sketch below during battery replacing Please pay much attention to the polarity of the battery F Ee sdi Procedure UTG Alpha 1 Power Off the instrument 2 Take off the cover of the battery and take out the two batteries 3 Insert the new batteries into the instrument 4 Replug the battery cover 5 Power on the instrument to check EE E F GE SaluTr
18. mon materials and their sound velocities can be found in Appendix A of this manual On the measurement screen press the key multiple times to tab to the sound velocity item Press the key to switch among the preset commonly using velocities Use the 2 key and the e key to adjust the sound velocity value up or down until it matches the sound velocity of the material to be measured Press the key to exit from the calibration mode The gauge is now ready to perform measurements Another method to set the instrument with a known sound velocity is as following Highlight the Test Set gt Velocity Set submenu item press to enter the sound velocity set screen Press the E key multiple times to tab to the numeric digit to be changed Use the e key to increase decrease numeric values on the display until it matches the sound velocity of the material to be measured An auto repeat function is built in so that when the key is held down numeric values will increment decrement at an increasing rate Press the key to confirm the modifying or press the key to cancel the calibration To achieve the most accurate measurements possible it is generally advisable to always calibrate the gauge to a sample piece of known thickness Material composition and thus its sound velocity sometimes varies from lot to lot and from manufacturer to manufacturer Calibration to a sample of known thickness will ensure that the gauge is
19. nager System Set View Mem Data Delete by File Delete all Data 4 7 6 2 g n D sed lt 5 D 3 pe O 6 Auto Save Key Sound Warn Sound LCD Brightness 5 1 Enter the Main Menu To enter the main menu just press the key to activate the menu items tab while on the measurement screen To return back to the previous screen press the key 5 2 Enter the Sub menu Press the key to enter the submenu screen while the submenu item is selected 5 3 Change the Parameter Press the key to change the value of a parameter while the item is selected on the parameter set screen 5 4 Numeric Digit Input Use the key multiple times to tab to the numeric digit to be changed Use the ke key to increase decrease numeric values on the display until it matches the desired value 5 5 Save and Exit Press the key to confirm the modifying and return back to the previous screen 5 6 Cancel and Exit Press the key to cancel the change and return back to the previous screen 18 6 Servicing When the hardness tester appears some other abnormal phenomena please do not dismantle or adjust any fixedly assembled parts Fill in and present the warranty card to us The warranty service can be carried on 7 Transport and Storage Keep it away from vibration strong magnetic field corrosive medium dumpiness and dust Storage in ordinary temperature With original packing transport is allowed on the third grade highway
20. nt Calibration function 5 Two work modes Single point mode and Scan mode Coupling status indicator showing the coupling status Battery information indicates the rest capacity of the battery Auto sleep and auto power off function to conserve battery life Optional software to process the memory data on the PC Optional thermal mini printer to print the measured data via RS232 port 1 3 Measuring Principle The digital ultrasonic thickness gauge determines the thickness of a part or structure by accurately measuring the time required for a short ultrasonic pulse generated by a transducer to travel through the thickness of the material reflect from the back or inside surface and be returned to the transducer The measured two way transit time is divided by two to account for the down and back travel path and then multiplied by the velocity of sound in the material The result is expressed in the well known relationship poe 2 Where H Thickness of the test piece v Sound Velocity in the material t The measured round trip transit time 1 4 Configuration Table 1 1 C aaa 22 2 Standard Main body EE ZE Configur 2 Transducer 1 Model ation N05 90 EE 3 Couplat JI as 4 instrument Case 1 5 LOperating Manual 1 6 Screwdriver Ji E27 ee e R Optional Transducer N02 J See Configur Transducer NO7 Table3 1 ation Transducer HT5 Mini thermal 1 rte Print cable 1 1 DataPro for For
21. of the instrument It transmits and receives ultrasonic sound waves that the instrument uses to calculate the thickness of the material being measured The transducer connects to the instrument via the attached cable and two coaxial connectors When using transducers the orientation of the dual coaxial connectors is not critical either plug may be fitted to either socket in the instrument The transducer must be used correctly in order for the instrument to produce accurate reliable measurements Below is a short description of the transducer followed by instructions for its use 10 Left figure is a bottom view of a typical transducer The two semicircles of the wearface are visible as is the barrier separating them One of the semicircles is responsible for conducting ultrasonic sound into the material being measured and the other semicircle is responsible for conducting the echoed sound back into the transducer When the transducer is placed against the material being measured it is the area directly beneath the center of the wearface that is being measured 11 Right figure is a top view of a typical transducer Press against the top with the thumb or index finger to hold the transducer in place Moderate pressure is sufficient as it is only necessary to keep the transducer stationary and the wearface seated flat against the surface of the material being measured Table 3 1 Transducer Selection Model Freq Diam M
22. on Cathode Please take out the batteries when not working during a long period of time Suggest to replace the batteries when the battery capacity indicator shows half capacity 4 17 Auto Power Off The instrument features an auto power off function designed to conserve battery life If the tool is idle for 5 minutes it will turn itself off While the voltage of the battery is too low this function will also work 16 4 18 System Reset Press down the key while powering on the instrument will restore factory defaults All the memory data will be cleared during system reset The only time this might possibly helpful is if the parameter in the gauge was somehow corrupted 4 19 Connecting to a Computer The gauge is equipped with an RS232 serial port Using the accessory cable the gauge has the ability to connect to a computer or external storage device Measurement data stored in the memory of the gauge can be transferred to the computer through the RS232 port Detailed information of the communication software and its usage refer to the software manual 17 5 Menu Operation Both presetting system parameters and the additional function could come true by menu operation At the measurement screen press the key into the main menu Work mode 2 Point Cal Velocity Set Probe Set Tolerance Limit Resolution Unit Print Current Print Memory Print All Mem Test Set Print Set Memory Ma
23. on its temperature As materials heat up the velocity of sound through them decreases In most applications with surface temperatures less than about 100 C no special procedures must be observed At temperatures above this point the change in sound velocity of the material being measured starts to have a noticeable effect upon ultrasonic measurement At such elevated temperatures it is recommended that the user perform a calibration procedure on a sample piece of known thickness which is at or near the temperature of the material to be measured This will allow the gauge to correctly calculate the velocity of sound through the hot material When performing measurements on hot surfaces it may also be necessary to use a specially constructed high temperature transducer These transducers are built using materials which can withstand high temperatures Even so it is recommended that the probe be left in contact with the surface for as short a time as needed to acquire a stable measurement While the transducer is in contact with a hot surface it will begin to heat up and through thermal expansion and other effects may begin to adversely affect the accuracy of measurements Measuring laminated materials Laminated materials are unique in that their density and therefore sound velocity may vary considerably from one piece to another Some laminated materials may even exhibit noticeable changes in sound velocity across a single surface The on
24. point calibrations must be performed on material with the paint or coating removed Failure to remove the paint or coating prior to calibration will result in a multi material velocity calculation that may be different from the actual material velocity intended to be measured 4 4 1 Calibration to a known thickness 1 Note This procedure requires a sample piece of the specific material to be measured the exact thickness of which is known e g from having been measured by some other means Perform a Probe Zero Apply couplant to the sample piece Press the transducer against the sample piece making sure that the transducer sits flat against the surface of the sample The display should show some thickness value and the coupling status indicator should appear Having achieved a stable reading remove the transducer If the displayed thickness changes from the value shown while the transducer was coupled repeat step 3 Use the Le key and the e key to adjust the displayed thickness up or down until it matches the thickness of the sample piece Press the key The gauge is now displaying the sound velocity value it has calculated based on the thickness value that was entered Press the key to exit the calibration mode The gauge is now ready to perform measurements 4 4 2 Calibration to a known velocity 1 DIED Note This procedure requires that the operator knows the sound velocity of the material to be measured A table of com
25. sed in ultrasonic gauging Propylene glycol is suitable for most applications In difficult applications where maximum transfer of sound energy is required glycerin is recommended However on some metals glycerin can promote corrosion by means of water absorption and thus may be undesirable Other suitable couplants for measurements at normal temperatures may include water various oils and greases gels and silicone fluids Measurements at elevated temperatures will require specially formulated high temperature couplants Inherent in ultrasonic thickness measurement is the possibility that the instrument will use the second rather than the first echo from the back surface of the material being measured while in standard pulse echo mode This may result in a thickness reading that is TWICE what it should be The Responsibility for proper use of the instrument and recognition of these types of phenomenons rest solely with the user of the instrument 22 een T SaluTron GmbH Salu Tron Messtechnik GmbH Max Planck Str 62 D 32105 Bad Salzuflen Tel 49 0 5222 959760 Fax 49 0 5222 50499 Email info salutron de www salutron de
26. set as closely as possible to the sound velocity of the material to be measured 4 5 Making Measurements 1 2 When the tool is displaying thickness measurements the display will hold the last value measured until a new measurement is made In order for the transducer to do its job there must be no air gaps between the wear face and the surface of the material being measured This is accomplished with the use of a coupling fluid commonly called couplant This fluid serves to couple or transfer the ultrasonic sound waves from the transducer into the material and back again Before attempting to make a measurement a small amount of couplant should be applied to the surface of the material being measured Typically a single droplet of couplant is sufficient After applying couplant press the transducer wearface down firmly against the area to be measured The coupling status indicator should appear and a number should appear in the display If the instrument has been properly zeroed and set to the correct sound velocity the number in the display will indicate the actual thickness of the material directly beneath the transducer If the coupling status indicator does not appear or the numbers on the display seem erratic firstly check to make sure that there is an adequate film of couplant beneath the transducer and that the transducer is seated flat against the material If the condition persists it may be nece
27. ssary to select a different transducer size or frequency for the material being measured While the transducer is in contact with the material that is being measured the instrument will perform four measurements every second updating its display as it does so When the transducer is removed from the surface the display will hold the last measurement made 12 Note Occasionally a small film of couplant will be drawn out between the transducer and the surface as the transducer is removed When this happens the gauge may perform a measurement through this couplant film resulting in a measurement that is larger or smaller than it should be This phenomenon is obvious when one thickness value is observed while the transducer is in place and another value is observed after the transducer is removed In addition measurements through very thick paint or coatings may result in the paint or coating being measured rather than the actual material intended The responsibility for proper use of the instrument and recognition of these types of phenomenon rest solely with the user of the instrument 4 6 Two Point Calibration 1 2 9 Note This procedure requires that the operator has two known thickness points on the test piece that are representative of the range to be measured On the Test Set gt 2 Point Cal submenu item press l to toggle the Two Point mode to ON Then exit from the menu to the measurement screen The string D
28. to cancel the change If the limit setting exceeds the measurement range the gauge vvill remind you to re set If the bottom limit is larger than the upper limit the values vvill be exchanged automatically 4 9 Resolution The gauge has selectable display resolution which is 0 1mm and 0 01mm On the Test Set gt Resolution menu item press the key to switch between High and Lovv 4 10 Unit Scale On the Test Set gt Unit menu item press the key to switch back and forth between Engilish and metric units 4 11 Memory Management 4 11 1 Storing a reading There are twenty files FOO F19 that can be used to store the measurement values inside the gauge At most 99 records can be stored to each file The following procedures outline this process Press the key to activate the File Name item on the main measurement screen 1 Use the 2 key and the e key to select the desired file to save the data 2 After anew measurement reading appears press the key to save the measurement value to current file If the Auto Save function is enabled the measurement value will be automatically saved to current file after a new measurement operation 4 11 2 Viewing stored readings Press the key multiple times until the Record No area On the measurement screen is highlighted Use the Le key and the e key to change the record number The gauge will automatically read the stored va
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