PUNDITplus Manual

OPERATING INSTRUCTIONS

PUNDITplus MODEL PC1006

CNS Farnell Limited Elstree Business Centre, Elstree Way,

Borehamwood, Hertfordshire, England. WD6 1RX

Telephone: +44 (0)20 8238 6900 Facsimile: +44 (0)20 8238 6901

Email: [email protected] Website: www.cnsfarnell.com

2 © CNS Farnell Limited. March 2006.

The contents of this operating manual are the property of CNS Farnell Limited and are copyrighted. Any reproduction in whole or in part is strictly prohibited. For additional copies, please contact CNS Farnell Limited.

DOC0016 ISS.5

CNS Farnell Limited PUNDIT plus 3

CONTENTS SECTION PAGE

1. Introduction 4 2. First steps 5 3. Setup parameters 7 4. Transit time 10 5. Path length 12 6. Velocity / Limits 14 7. Elastic modulus 17 8. Battery test 19 9. Zero / Download 20 10. Storing readings 22


1. INTRODUCTION The PUNDIT plus is the latest development in the PUNDIT range of ultrasonic test equipment. It offers new features to make it the most flexible ultrasonic test system available on the market today. New features include: • Three modes of pulse generation: continuous, delayed or one-shot • Three operating voltages: 250V, 500V and 1200V • Five display options: transit time, path length, velocity, limits and elastic modulus • Metric or imperial measurement units • Memory logging facility: with continuous and manual modes to store up to 112

readings • Button on receiving transducer: facilitates manual memory log function • Remote input: enables PUNDIT plus to be controlled by external systems • Download function: enables stored readings to be transferred to a PC

The above features have been designed to make the PUNDIT plus a simple to use, yet extremely flexible, test system.


2. FIRST STEPS Before the PUNDIT plus system can be used follow these steps: 2.1 Connect transducers

There are two transducers in the kit. The receiving transducer has a button. The transmitter does not. Each transducer has its own cable. The transmitter’s cable has a connector with one single pin only at each end. The receiver’s cable has a connector with a single pin and a socket at each end. Please note that the cables may not be interchanged. Connect the appropriate cables to the Tx and Rx sockets on the rear panel of the PUNDIT plus.

Connect the relevant transducers to the other ends of the cables.

2.2 Switch unit on

Switch the on/off/charge switch on the rear panel to the ‘ON’ position. Use the ‘Contrast’ control on the rear panel to adjust the display to give the best display. The contrast may need to be adjusted, depending upon the viewing angle and ambient light conditions. The LCD backlight is off when the unit is switched on. When the ambient light is not sufficient to read the display, the backlight can be toggled on and off, at any time, using the ‘Del’ key. The following main menu screen will appear on the display:

Fig.1 - Main menu


2.3 Check battery level Check the battery level following the procedure described in section 8 and re-charge if necessary. Alternatively, the unit can be powered using the external power supply - if this is practical. When using the external power supply, simply plug it into the AC mains and the PUNDIT plus and switch the on/off/charge switch to the ‘ON’ position. NB. As with all ultrasonic test systems, the PUNDIT plus should not be used in situations where excessive external mechanical vibrations exist as this may cause erroneous readings.


3. SETUP PARAMETERS The first step in using the PUNDIT plus test system is to define the parameters for the preferred mode of operation. To do this select item 1 from the main menu options by pressing ‘1’ on the keypad. The following display will appear:

Fig.2 - Setup parameter screen When any of the parameters are changed, in any of the screens, on the PUNDIT plus,they are saved and restored the next time the unit is switched on. In this way the user can configure the PUNDIT plus once and not have to repeat the same steps after turning the unit off.

3.1 EHT Voltage

The EHT voltage is the voltage level of the transmitter pulse. There are three to choose from: 250V, 500V and 1200V. As a rule of thumb, this should be set to 500V for most concrete applications. However, if the path length is large or if the material under test attenuates the received signal excessively, it may be necessary to increase the EHT voltage to 1200V. Conversely, small path lengths may require the lesser EHT voltage of 250V to be used. To change the EHT voltage, use the up/down arrow keys to move the cursor to the ‘EHT VOLTAGE>…’ line and then use the right arrow key to step through the options. When the preferred option is displayed, use the up/down arrow keys to move to the next parameter to be changed, or press the ‘menu’ key to record the parameters and go back to the main menu.


3.2 Units

The PUNDIT plus can display readings with either metric or imperial units. Use the up/down arrow keys to move the cursor to the ‘UNITS…’ line and then use the right arrow key to toggle between the options, ‘METR’ or ‘IMP’.

3.3 Pulse mode There are three ways in which pulses can be generated. They can be generated continuously at a fixed pulse repetition frequency, they can be delayed by a fixed period specified in seconds, minutes and hours or they can be generated once only, on demand, on a one-shot basis. To change the Pulse mode, use the up/down arrow keys to move the cursor to the ‘PULSE MODE >…’ line and then use the right arrow key to step through the options, ‘CONT’, ‘DELAY’ or ‘ONE’. When the preferred option is displayed, use the up/down arrow keys to move to the next parameter to be changed, or press the ‘menu’ key to record the parameters and go back to the main menu.

3.4 Log mode Before using the memory function of the PUNDIT plus, its operating mode must be defined using the ‘LOG MODE’ parameter. Readings can be recorded continuously, on demand or not at all. Hence the log modes are ‘CONT’, ‘ONE’ or ‘OFF’ respectively. To change the Log mode, use the up/down arrow keys to move the cursor to the ‘LOG MODE…’ line and then use the right arrow key to step through the options, ‘CONT’, ‘ONE’ or ‘OFF’. When the preferred option is displayed, use the up/down arrow keys to move to the next parameter to be changed, or press the ‘menu’ key to record the parameters and go back to the main menu.

3.5 Pulse repetition frequency If the continuous pulse mode has been selected, then a pulse repetition frequency (PRF) is required. The PRF is simply the rate at which pulses are produced by the transmitter and is expressed as the number of pulses per second. The default PRF is 10 pulses per second. PRFs in excess of 50 should only be used when a scope is connected as the display will be blanked. To change the pulse repetition frequency, use the up/down arrow keys to move the cursor to the ‘PULSE R.F.…’ line and use the number keys to enter the required PRF in the range of 1 to 100.


Note that the PRF does not need to be entered if the delayed or one-shot mode is selected. When the PRF has been entered, use the up/down arrow keys to move to the next parameter to be changed, or press the ‘menu’ key to record the parameters and go back to the main menu.

3.6 Pulse delay If the delayed pulse mode has been selected, then a delay period is required. The delay period is simply the time between transmitter pulses. It can be expressed in multiples of seconds, minutes and hours The default delay period is 30 seconds, 0 minutes and 0 hours. To change the delay period, use the up/down arrow keys to move the cursor to the ‘PULSE DELAY.…’ line and use the number keys to enter the required number of hours in the range of 0 to 99. Use the down arrow key to move the cursor to the minutes line and enter a value in the range 0 to 59. Again use the down arrow key to move the cursor to the seconds line and enter a value in the range of 0 to 59. Note that the delay does not need to be entered if the continuous or one-shot mode is selected. When the delay has been entered, use the up/down arrow keys to move to the next parameter to be changed, or press the ‘menu’ key to record the parameters and go back to the main menu.


4. TRANSIT TIME Transit time is the fundamental measurement of the Pundit plus system. All of the other measurements, such as path length, velocity, etc, are derived using this basic measurement in addition to other entered parameters such as velocity, path length, etc. The transit time is the time it takes for the ultrasonic pulse to pass from the transmitter to the receiver. To display the transit time, select option 2 from the main menu. The transit time parameter screen will then appear:

Fig. 3 - Transit time parameter screen.

The resolution may be set to 0.1µs or 1µs. If a resolution of 0.1µs is selected then the measurement range will be from 0 to 999.9µs in 0.1µs steps. A resolution of 1µsenables a range of 0 to 9999µs to be covered in 1µs steps. To change the resolution, use the up/down arrow keys and move the cursor to the ‘RESOLUTION…’ line. Use the right arrow key to toggle between the available options of 0.1µs and 1µs.When displaying transit times, the correction factor should be set to 100%. (If the transducers have not been ‘zeroed’ then this must be done now. Press the ‘menu’ key twice to return to the main menu. See section 9 for the procedure for zeroing the transducers.) Apply gel to the transducers and place the transducers onto the sample. Press the ‘menu’ key to load the Transit time screen:


Fig. 4 - Transit time screen.

To start the pulse generator press the ‘run/stop’ key. The transmitter should start ‘ticking’ (depending upon the pulse mode in use) and the transit time should be displayed. If the time taken for the signal to be received exceeds the range being used, an ‘OVER-RANGE’ message will appear in place of the transit time. Three successive over ranges will result in a ‘LOST SIGNAL’ message being displayed. Pressing the ‘run/stop’ key a second time will either halt the pulse generator (for the continuous or delayed modes) or generate another pulse (in the one-shot) mode. The ‘run/stop’ key can be pressed at any time while the pulse generator is paused or running to start or stop the pulse generator. To store a reading, press the ‘enter’ key, the button on the receiver transducer or the remote button (if connected). Refer to section 10 for details on the memory storage functions. To escape from the transit time section, press the ‘menu’ key. The main menu will re-appear.


5. PATH LENGTH It is possible to calculate the path length between the two transducers if the transit time and the speed of sound (velocity) through the material are known. This is given by the relationship:

Path length = Velocity x Transit time As mentioned earlier, the fundamental measurement of the PUNDIT plus is transit time. Hence to calculate the path length, the velocity must be entered. To display the path length, select option 3 from the main menu. The path length parameter screen will then appear:

Fig. 5 - Path length parameter screen. Enter the velocity by moving the cursor key to the ‘VELOCITY…’ line and typing an integer value in the range of 1 to 9999 m/s. A correction factor may be entered if desired. Correction factors may be necessary if reinforcing steel is present. Refer to the CNS Farnell Technical Reference Manual for further details. The resolution for the transit time must be set in the transit time section. See section 4 above. (If the transducers have not been ‘zeroed’ then this must be done now. Press the ‘menu’ key twice to return to the main menu. See section 9 for the procedure for zeroing the transducers.) Apply gel to the transducers and place the transducers onto the sample. Press the ‘menu’ key to load the Path length screen:


Fig. 6 - Path length screen. To start the pulse generator press the ‘run/stop’ key. The transmitter should start ‘ticking’ (depending upon the pulse mode in use) and the path length should be displayed. If the time taken for the signal to be received exceeds the range being used, an ‘OVER-RANGE’ message will appear in place of the transit time. Three successive over ranges will result in a ‘LOST SIGNAL’ message being displayed.

Pressing the ‘run/stop’ key a second time will either halt the pulse generator (for the continuous or delayed modes) or generate another pulse (in the one-shot) mode. The ‘run/stop’ key can be pressed at any time while the pulse generator is paused or running to start or stop the pulse generator. To store a reading, press the ‘enter’ key, the button on the receiver transducer or the remote button (if connected). Refer to section 10 for details on the memory storage functions. To escape from the path length section, press the ‘menu’ key. The main menu will re-appear.


6. VELOCITY / LIMITS One of the most common applications of the PUNDIT plus system is the calculation of pulse velocity. Pulse velocity can be displayed if the transit time and path length are known. This is given by the relationship:

Velocity = Path length / Transit time To select the velocity mode select option 4 from the main menu. The velocity parameter screen will then appear:

Fig.7 - Velocity parameter screen

Before going any further, it is worth mentioning that there are two different velocity display modes. The first shows the velocity as the more conventional ‘number on screen’. The second mode simply states whether the velocity is higher, lower or within a range of limits.

The choice of mode is made by moving the cursor to the ‘VEL/LIMITS…’ line and using the right arrow key to select either ‘VEL’ or ‘LIMIT’. Use the arrow and number keys to enter the path length and correction factor in the usual manner. If the ‘LIMIT’ mode has been selected, enter lower and upper limits for the velocity. The resolution for the transit time must be set in the transit time section. See section 4 above. (If the transducers have not been ‘zeroed’ then this must be done now. Press the ‘menu’ key twice to return to the main menu. See section 9 for the procedure for zeroing the transducers.) Apply gel to the transducers and place the transducers onto the sample. Press the ‘menu’ key to display the velocity or limits screen. If the velocity mode was selected


the velocity screen will appear:

Fig. 8 - Velocity screen

To start the pulse generator press the ‘run/stop’ key. The transmitter should start ‘ticking’ (depending upon the pulse mode in use) and the velocity should be displayed. If the time taken for the signal to be received exceeds the range being used, an ‘OVER-RANGE’ message will appear in place of the velocity. Three successive over ranges will result in a ‘LOST SIGNAL’ message being displayed. Pressing the ‘run/stop’ key a second time will either halt the pulse generator (for the continuous or delayed modes) or generate another pulse (in the one-shot) mode. The ‘run/stop’ key can be pressed at any time while the pulse generator is paused or running to start or stop the pulse generator. To store a reading, press the ‘enter’ key, the button on the receiver transducer or the remote button (if connected). Refer to section 10 for details on the memory storage functions. To escape from the velocity section, press the ‘menu’ key. The main menu will re-appear. If the velocity limits mode was selected, then the limits screen shown in Fig 9 will appear instead. To start the pulse generator press the ‘run/stop’ key. The transmitter should start ‘ticking’ (depending upon the pulse mode in use). The ‘LO’ message appears if the pulse velocity is less than the lower limit. The ‘HI’ message appears if the velocity is greater than the upper limit. If the velocity is in between the limits, then the ‘OK’ message appears. If the time taken for the signal to be received exceeds the range being used, an ‘OVER-RANGE’ message will appear in place of the ‘HI’, ‘OK’ or ‘LO’ message. Three successive over ranges will result in a ‘LOST SIGNAL’ message being displayed.


Fig. 9 - Velocity limits screen Pressing the ‘run/stop’ key a second time will either halt the pulse generator (for the continuous or delayed modes) or generate another pulse (in the one-shot) mode. The ‘run/stop’ key can be pressed at any time while the pulse generator is paused or running to start or stop the pulse generator. To escape from the velocity limits section, press the ‘menu’ key. The main menu will re-appear.


7. ELASTIC MODULUS When using earlier models of the PUNDIT system to calculate the elastic modulus of a material, it was first necessary to measure the transit time, then calculate the velocity and hence the elastic modulus. The Pundit plus can display the elastic modulus directly without the intermediate steps. Some basic parameters must first be entered, such as path length, correction factor (if required), density and Poisson’s ratio and the PUNDIT plus does the rest. The elastic modulus is given by the equation: Elastic modulus, Ed = ρv2(1+σ)(1-2σ) / (1-σ)

where: ρ = density v = velocity σ = Poisson’s ratio To display the elastic modulus select option 5 from the main menu. The elastic modulus parameter screen will then appear:

Fig. 10 - Elastic modulus parameter screen Use the arrow and number keys to enter the path length (0.01 to 99.99m), correction factor (1-100%), density (1-9999kg/m3) and Poisson’s ratio (0.0001 to 0.4999), in the usual manner. The resolution for the transit time must be set in the transit time section. See section 4 above. (If the transducers have not been ‘zeroed’ then this must be done now. Press the ‘menu’ key twice to return to the main menu. See section 9 for the procedure for zeroing the transducers.) Apply gel to the transducers and place the transducers onto the sample. Press the ‘menu’ key to display the Elastic Modulus screen:


Fig. 11 - Elastic modulus screen

To start the pulse generator press the ‘run/stop’ key. The transmitter should start ‘ticking’ (depending upon the pulse mode in use) and the elastic modulus should be displayed. If the time taken for the signal to be received exceeds the range being used, an ‘OVER-RANGE’ message will appear in place of the elastic modulus. Three successive over ranges will result in a ‘LOST SIGNAL’ message being displayed. Pressing the ‘run/stop’ key a second time will either halt the pulse generator (for the continuous or delayed modes) or generate another pulse (in the one-shot) mode. The ‘run/stop’ key can be pressed at any time while the pulse generator is paused or running to start or stop the pulse generator. To store a reading, press the ‘enter’ key, the button on the receiver transducer or the remote button (if connected). Refer to section 10 for details on the memory storage functions. To escape from the elastic modulus section, press the ‘menu’ key. The main menu will re-appear.


8. BATTERY TEST To check the battery voltage select option 7 from the main menu. The battery voltage will then appear on the battery voltage display screen:

Fig.12 - Battery Voltage screen

When the battery voltage has fallen below 6.0V it will be necessary to charge the batteries. If it is not possible to charge the batteries on site, then conventional primary cells (non re-chargeable cells) may be used in place of the NiMH batteries. The battery pack is accessed by removing the bottom cover. To charge the NiMH batteries, plug the external power supply into the mains and PUNDIT plus and switch the on/off/charge switch to the ‘CHARGE’ position. The batteries will be charged in approx. 16 hours. Please ensure that the on/off/charge switch is turned to the ‘OFF’ position after charging. WARNING: Do not attempt to charge non re-chargeable cells as this could result in fire.


9. ZERO / DOWNLOAD The PUNDIT plus transit time measurement system has an inherent time delay caused by the cables, transducers and electronics, etc. To remove the effects of this delay it is necessary to ‘zero’ the transducers, so that accurate readings will be made. To zero the transducers, select menu option 8. Apply the coupling gel to the face of one transducer and then place the transducers face to face. Press the ‘1’ key. The display will flicker momentarily and the transmitter will be pulsed once. A reading will be taken. The value obtained will be subtracted from all future readings to give correct transit times. Please note that it is recommended that the instrument be turned off and on again each time before zeroing the transducers. To return to the main menu, press the ‘menu’ key.

Fig. 13 - Zero / Download screen.

To download data to a PC, select menu option 8. Connect the PC to the PUNDIT plus and start the PC’s terminal program (in Windows this is usually ‘Terminal’ or ‘Hyperterminal’, with the communications parameters set to 9600 baud, no parity, 8 data bits and 1 stop bit. Press key ‘2’ and the following message will appear until all of the data has been downloaded to the PC:


Fig. 14 - Download message.

The Zero/Download screen will re-appear when the data has been downloaded. Press the ‘menu’ key to return to the main menu. The downloaded data format is as follows:

aaaaa<cr> 5 digit ascii number containing the screen reference, e.g. 00002 is the basic time screen, 00003 is the path screen, etc. This is necessary to define how some of the later parameters have been obtained.

bbbbb<cr> 5 digit ascii number containing the user-entered or automatic

memory reference numbers. ccccc<cr> 5 digit ascii number specifying the time measured. The format

is 0nnnn or nnn.n depending on whether the unit was recording in 1µs or 0.1µs mode.

X<cr> Single ascii character indicating the measurement units in use. I

= Imperial units, M = metric units. fffff<cr> 5 digit ascii number denoting the correction factor in %. The

format is 00nnn. ddddd<cr> 5 digit ASCII number containing the path length. The format is

0nnnn or nn.nn, depending on the displayed output for path length on the screen (mm, metres or 1/100 feet).

eeeee<cr> 5 digit ascii number for velocity. ggggg<cr> 5 digit ascii number for density. hhhhh<cr> 5 digit ascii number for Poisson's ratio. The format is 0nnnn ( =

0.nnnn). kkkkk<cr> 5 digit ascii number for resonant frequency. Not used. YYY<cr> 3 digit ascii number for cement type. The format is PFA or

POR. Not used. mmmmm<cr> 5 digit ascii number for rebound number. Not used.


10. Storing readings If the continuous log mode was selected on the setup parameters screen (see section 3), then the unit will automatically start storing readings whenever the ‘run/stop’ button is pressed. It will stop when either the ‘run/stop’ button is pressed again or the memory is full. In the continuous mode the unit will remember its logging reference number (even if the unit is turned off) and increment it automatically. The logging reference number will be reset to 1 when the memory is cleared. In the manual logging mode, measurements can be stored by pressing the ‘enter’ key, the button on the receiver transducer or the remote button (if connected) while in any one of the transit time, path length, etc. measurement screens. The following memory screen will then appear:

Fig. 15 - Memory Screen

The user will be given the choice of entering a reference number or deleting the memory. To enter a reading reference (of up to 3 digits in length), use the numeric keys and then press the ‘enter’ key. Alternatively if the memory is to be cleared, move the cursor to the ‘DELETE MEM…’ line and press the right arrow key. The memory will be cleared and the message ‘done’ will appear. Press the ‘menu’ key to return to the previous screen.


Once the memory is full, the following screen will appear:

Fig. 16 Memory full screen.

To return to the previous screen without clearing the memory, press the ‘menu’ key. Note that if the unit was operating in the continuous logging mode, it will return to the previous screen and change the logging mode to manual. If the memory is to be cleared, move the cursor to the ‘DELETE MEM…’ line and press the right arrow key. The memory will be cleared and the message ‘done’ will appear. Press the ‘menu’ key to return to the previous screen.

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PUNDITplus Manual