ISO Human exposure vibration analysis

Good Morning,
I am trying to use LabView 7.1 with the Sound and Vibration toolkit in processing some data in accordance with ISO 5349-1:2001. In this standard, data needs to be collected in 1/3 octave bands from 6.3Hz to 1250Hz then weighted and the RMS taken. Data collection and RMS are not a problem, the challenge I am having is with the octave analysis and creating the custom weighting. Am I just missing the obvious VI's in SVT 3.1? Is there a custom weighting example? How does one perform octave analysis below the low frequency cut-offs of the existing VI's?
Thanks,
DRK

Hi DRK,
thanks for posting again. A few things:
1) In the same user manual on pages 9-9 and 9-10 there's this info:
Performing Third-Octave Analysis Outside the Audio Range
You might need to perform third-octave analysis on signals outside of the
20 Hz–20 kHz range. For example, you might need to evaluate human
exposure to whole body vibration with potential signals of interest in
the 0.5 Hz–80 Hz range. To perform third-octave analysis outside the
20 Hz–20 kHz range, use either the SVT Fractional-octave Analysis
[ANSI] VI or the SVT Fractional-octave Analysis [IEC] VI and select a
bandwidth equal to 1/3 octave, as illustrated in Figure 9-7.
2)We don't have a weighting filter according to that standard currently but we would like to discuss the standard a little more with you, if possible. Can you give us a phone number (preferably) or an email address that we can contact you at?
Thanks!
Brian Spears

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Rule of thumb for the number of averages in an FFT for vibration analysis?

I'm doing vibration analysis on rotating machinery and would like to average the FFT to minimize variations of the data (rms averaging). How does one choose the optimum number of averages?
Also, why is it necessary to specify the number of averages (for example, in the Spectral Measurements express VI) as well as telling the VI to restart averaging. Would not the latter would be sufficient when the Spectral Measurements VI is enclosed in a loop? Thanks.

Thanks for your post.
In my experience 20 is a good number. It really depends however on a number of factors.
1) does the frequency of the rotation of the machine (speed) change? If so, averaging from an FFT would not work well. I would use the Order Spectrum in the Sound and Vibration Measurement Suite if speed changes.
2) are loads changing (and speed is constant or you are using order spectrum)? If so you will want a smaller number of averages so you do not average out the effect of fast load changes.
3) try a few numbers and note when the noise floor appears stable. This may be the best method to choose the number.
4) how often do you want a result? A smaller number of averages will produce an "averae complete" result more often.
Use the averages complete boolean to gate passing on the results (to the user interface, file, further analysis, etc.). With restart averaging on, it will restart another averaging process and toggle the boolean (gate).
Hope this helps.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

About Vibration analysis of machine using wavelet analysis and extraction techniques

I want to perform vibration analysis using accelerometer and NI DAQ please help me in VI development and how and which parameters should i extract from the raw signal. About Vibration analysis of machine using wavelet analysis and extraction techniques.
Nitesh Parmar
+91-9780900184
[email protected]

Lynn,
Thanks for the reply.
I'm attaching some pictures of the test rig. As you can see, we have a small servo motor sitting on top of the bearing, which is a small needle/thrust bearing, used in the planetary gears of automatic transmissions. The readings are being taken by a general purpose 100mV/g accelerometer, which you can see is mounted on the bottom of a fairly thick steel plate. I understand there can be some transmissibility problems when going through too much material? We seem to be getting a reading though. The only weight on the bearing is the motor and mounting plate, 5-10lbs. I considered adding weight, and that will probably be my next move.
I'm also attaching some runs I've made. One set is of a brand new bearing, the other set is of one I stuck in a sandblaster. It is now very obviously damaged, rough and noisy when you turn it. You should be able to open these files with the .vi attached to my previous post. The first tab will be the waveform, raw data. It is not accurately calibrated to g's, but I think it should be in the ballpark. The runs are comparable to each other anyway.
I'm not currently alligning the readings with the motor revolution. Maybe this is something I should look into? I have a very capable motor/drive setup for this...
I was previously using a legacy daq device, with which I couldn't wire the error lines into the digital line write tool. You are correct that I can now remove the while loops.
Whatever else I can provide to help you assist me here, let me know.
Thanks for the feedback.
Jeremy Backer
CLAD
Attachments:
Bearing Pics.zip ‏898 KB
Brand New.zip ‏3429 KB
Sand Blasted.zip ‏3426 KB

Portable vibration analysis cRIO technology???

How can I do a portable vibration analysis with cRIO technology and LabVIEW software?. Is it possible a FFT analysis in situ with
a PDA?. I relly apreciated your help. Thanks.

Jorge,
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Let me know if you need any more information.
cheers,
Brett

Need help with FFT for Vibration Analysis

Hello all,
I am acquiring data into LabVIEW from an accelerometer. The acceleration (in g's as determined within MAX) time domain graph works fine. However, I wish to do analysis using an FFT spectrum. All my attemps at wiring my time domain acceleration data into various FFT.vi's have resulted in blank graphs, including the sound and vibration module VI's. I am accquiring at 2000Hz. Obviously I am doing something wrong. Can anybody shed some light on how I can get a successful FFT working?
Kind Regards
Adam

I attached an example that works well for me - gens a signal, converts to waveform data type, does FFT
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444
Attachments:
Generate Signal and SV FFT.vi ‏20 KB
gen sig and fft.JPG ‏32 KB
gen sig and fft.JPG ‏32 KB

Sound and Vibration toolkit for vibration analysis

Hi guys! I am new to Labview. I am trying to use Sound and Vibration toolkit to analyse the accelerometer signal mounted on a motor through myRio. The analysis are spectral map, order tracking, power spectrum, order spectrum etc. But nothing can be seen from the output graph. The only result I get is from vibration level.
Attached is a screen shot of my vi and actual vi file. Am I doing it correctly? I really need your help guys....
Thanks.
Attachments:
Vib.vi ‏384 KB

SK,
You have serious problems in your File.VI. Why are your writing to your file and then reading it right back? Worse, there is no guarantee that the File write will actually occur before the File Read. You have a race condition set up there between those two Spreadsheet File VI's.
If you want to maintain a history of whatever has already been written to the file, you should be building it into an array and storing in a shift register. Even if your File.vi would by chance work the way you want it to, storing data in the file system is much slower than maintaining your data in memory.
As for your while loop, it is going to run as fast as it can with respect to all the functions occurring inside of it. Is it possible you are getting 14 iterations of that while loop for each frequency step that is occurring?
Message Edited by Ravens Fan on 07-25-2009 01:35 AM

Sound & Noise Vibration Analysis

Hi
We are testing a machine " Hypoid Gear Tester" basically for Acceptance or Rejection of Gear Production. We are testing PC base Labview software for this. We are using Microphone & Accelerometer for Analysis. The Enviroment is noisy 1) How to determine and elliminate this external noise 2) We need to generate a Graph or report as the attached file. I appreciate your help Thanks
Attachments:
Picture 022.jpg ‏595 KB

The order analysis tools and the sound and vibration tools provide the fundamental signal analysis for most all machinery vibration functions. However, the application level such as hammer blow test (modal), balancing, and so forth are not complete solutions.
I recommend looking at the following solution, which is based on these tools and comes with a turn-key application solution....
www.vibdaq.com
Let us know what further questions you have.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Understanding Vibration Analysis

First, I am very green, have taken Core 1 and Core 2 classes (Oct 2011), and have been modifying/writing small programs within my current abilities. We used to have a seasoned veteran, but he is no longer here, although my current question isn't specifically labview related. I have 2 files of data recorded in labview monitoring the analog output of a laser vibrometer. One is of a part with a loose crimp, the other is of a tight crimp and the raw waveforms are obviously very different. I am looking for a resource to help me understand what I can get out of this data, essentially on a beginner level. How do you process it to acquire frequencies, g levels, displacement, and other things I don't know about yet. A book recommendation would be fine, or should I be asking in another forum somewhere else?
Please note that I am already aware that the data recorded from the vibrometer may be suspect due to the requirements of taking that kind of data. That's all right for the moment, we will get better at this with time. I just do not have a good understanding of how to "mine" this data yet. A lot of learning to do....
Thanks for anything you can offer,
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Depending upon what failure mode(s) might exist for a "loose" crimp, there can be a number of things to look for. You might see easily-identifiable changes in the spectral content of the data (in which case you need an FFT), or it might be enough to simply track the maximum value. In any case, you will need a lot of examples to figure out what to look so you can separate the sheep from the goats.
Talk to the person who designed the widget and see if they can give any insight as to what they would expect during a failure. Also don't be surprised if (when?) you find that there are multiple features in the data that need to be balanced off one against the other.
Mike...
PS: One book recommendation for any data analysis project, Tukey's, Exploratory Data Analysis - aka. "The Red Book"
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LabVIEW Champion
"... after all, He's not a tame lion..."
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Repeatable Reading variation in Noise & Vibration Analysies

We are testing the Quality of the gears based on the noise and vibration produced when the bevel and the pinion gears mesh each other. We Using SV DAQ NI PCI-447 and connected accelerometer and microphone for 1st and 4th channel respectively. We are following signal harmonics method for the testing purpose. First, we acquire the data signals of both noise and vibration and process them by the same above method and judge wheatear the gear has some defects or not. (Based on the threshold values) The problem is, each time when we run the machine, the noise and vibration signals which we acquire will be different due to this final results (Harmonic values) are also changing. We need some filters or any other solution so that we acquire noise and vibration only for gear mesh. I uploaded a picture showing how we doing the test process for sound.
Attachments:
harmonic.png ‏35 KB

If you are only concerned about peaks within a certain frequency range, you should adjust the Search Range in the settings of the Peak Search Express VI (on the Configuration tab). That will tell the express VI to only return the peaks in the frequency range that you choose.
To clean up your results, you may want to try some FFT averaging. This might help if your peaks are jumping around a little bit due to a low peak threshold that might be picking up some noise.
If you really would like to do some filtering, you could use a highpass filter to get rid of any low order (1x/2x/3x, etc) vibration that you might not care about. From your picture, it looks like you have the Sound & Vibration Measurment Suite and you are comfortable using express VIs. So, you could use the filter express VI from the palette here: Sound and Vibration>>S&V Express Measurements>>Processing>>Filter.

6D vs 5d-mk3 for long exposure high ISO

Some on line info of unkown accuracy shows the 6D has better long exposure high ISO performance. This is known as amp glow.
The intended usage would be for astro phorotgraphy or night photgraphy where 30 second exposures at ISO1600 and up are required.
I already have a 5D-mk3 comming for evaluation where I will compare it to my 1DS-mk3. But I thought this is a good question for this forum. It seems strange that the lower cost camera would have supperior performance.
Anyone have personal experince or a technical explanation? Or is the information incorrect?
The same info also shows a vast improvement over the 1DS-mk3 and 5D-mk2

I know this topic is long dead, but somehow I was searching more comparisons at night shooting scenario between 6d vs 5dm3 and came across that topic (also in this forums here).
I think that below article comparing 6d to 5dm3 (and later also to 5dm2) at iso 3200 & 6400 with 15 sec & 30 sec exposure time, shows pretty good results in favor of 6D. the maker of that comparison also intended to use 6D camera for astrophotography.
http://petapixel.com/2012/12/13/canon-6d-and-5dmk3-noise-comparison-for-high-iso-long-exposures/
hope it helps.

Sound and vibration toolkit using Keithley Card

Hello everyone,
Might be doing a project soon using the LABVIEW Sound and Vibration Toolkit(1/n octave vibration analysis required) with LABVIEW 6.1(Sorry, try convince my Boss to upgrade). We have a Keithley KPCI-3101 card avaliable to us for the analog input.
Do any of you forsee a problem using a non-NI card with the sound and vibration toolkit? I can find very little on the internet discussing using non-NI cards with the toolkit.
This might sound like a stupid question but I need to be
100% sure that there are no problems.
Thank you for any help you can offer :-)
Cheers
Jurgen

Hello Jurgen,
Of course the integration with National Instruments boards (PCI-4472 or 445x boards) is best suited with the Sound and Vibration Toolkit. However it is possible to use the toolkit without National Instruments hardware. Most of the examples that ship with the toolkit use NI-DAQ data acquisition calls. You need to remove them from the examples and substitute them for the driver vi's that your board uses. There are also a couple of examples that use simulated signals (so there is no hardware at all involved).
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Also all the functions use the waveform datatype, (which include
s timing information), so you need to convert your array of data to this datatype, using the build waveform function.
Hope this answers your question.
Best regards,
Erik vH.
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National Instruments

Sound and vibration Toolkit 7.1 on Labview 8.0

Hello!
I kind of expect the answer is to cash out for a toolbox upgrade, but nevertheless I will ask the very logical question:
When I have an old Sound and Vibration Toolbox, how can I use it on a newer LabView Installation?
I could install, but when opening some of the example VI(SVXMPL_Averaged Frequency Response (DAQmx).vi), they do not work. The sub-VI's (e.g. svx_ClearAO_ClearAI (DAQmx).vi) have broken connections and even a mass compile didn't help. After the mass compile I have a long log of errors. So has anyone been successful in doing this without buying the newer version of the toolbox?

Hi
Let me double check the version of Sound and Vibration toolkit you installed
as the latest Sound and Vibration toolkit is version 6.0.
This information is in Measurement & Automation Explorer(MAX)
if you go to MySystem >> Software >> LabVIEW >> Sound and Vibration Analysis VIs.
As well as this, please let us know the version of your DAQmx driver.
It sounds many DAQmx VIs are broken and your DAQmx might not be a compatible version of the toolkit.
Regards,
Ayumi

600EX Flash - 5D III. Flash exposure compensation.

How can I set the FLASH exposure compensation from the CAMERA. It appears that I have to set the exposure compensation on the back of the flash unit. I would like be able to change the FLASH EC settings from the camera, not the flash unit.
Solved!
Go to Solution.

Ok, I have my 5D III out with my 600EX-RT mounted.
Let's make sure you don't have terminology confused.
There are two different compensations... there's "explosure compensation" and "flash exposure compensation".
If you meter exposure with the camera and then use the rear dial (assuming you did not disable it) after waking up the metering system then the rear dial will change the "exposure" compensation (this changes the metering for the AMBIENT light reading that the camera reads -- ignoring the flash). So changing "exposure compensation" will not change the flash even if the flash is powered on and connected. It would only change the camera.
On the top of the camera, just in front of the top LCD screen, there are four buttons. One has a dimple on it. That button is the ISO & "flash exposure compensation" button. If you press that button, then the rear LCD screen should show you that the rear dial will control "Flash exposure comp." Turning the rear dial at that point will make the adjustment show initially ONLY on the camera LCD screen... UNTIL you press the 'Set' button in the middle of the dial. Once you do that, the rear LCD screen on the flash will show that you have the flash exposure compensation enabled (it will ONLY show this when you wake up the metering system... if the metering system is allowed to go inactive the flash will only display the netural compensation... but as soon as you re-activate metering it will display your exposure compenation as set on the camera.
Also... on the rear LCD screen there's a box just below the ISO setting that shows if you have flash exposure compensation set and the amount.
This is all being controlled only by the camera -- I'm not using the menu buttons on the flash itself.
IF I DO use the buttons on the flash to set flash exposure compensation then the camera is locked out. It will report what compensation has been set on the flash, but will not let me change it until I use the buttons on the flash to return it to 0.
Does that help and are you able to do this with your flash?
Tim Campbell
5D II, 5D III, 60Da

GMLAN,J1939,J1587,J1508 Canbus Comms- Dynamometer, Sound and Vibration,Halt & Hass, Labview Consultant Available June '07

Will be available for 6-9 month contract June 07.
13 years Labview experience, GUI, SCADA, Canbus, Heavy Truck-Bus ECU verification, Dynamometer, Sound & Vibration Analysis. Environmental chamber shock testing experience, HALT-HASS, Durability and Life cycle, Executable VI development.

Need help with vibration integration and changing units

I am far from an expert in vibration, none the less I found the following table and am now trying to reverse engineer my data that I took with an accelerometer to something I can compare with on the table.
Screen 54 of the following said to go from G's to inches/sec2, multiply by 386.1 so I wrote up a piece of code to do that along with the labview sound and vibe toolkit. We know our machine has excessive vibration but this seems to be a little redicioulous. Am I doing this correctly, please see the attached code.
Essentially how do I go from Acceleration taken with a 10.82mV/g accelerometer to inches/second and mil peak to peak. I have tried using the integration functions but I am seeing numbers that just seem too big to be real.
Is there any example code on how to do this somewhere?
Thanks,
Adam

Thanks for the reply,
I have seen those examples but I am not sure they are helping me out too much, at issue is it seems like a lot of vibration data in the USA is based off of ips (inches per second) or displacement in mils peak to peak for example see the following image. I have done quite a bit of searching but am not necessiarly finding a good article that would describe how to code up something in LabVIEW to post process my recorded data taken in acceleration units of g's and convert it over to inches peak to peak as well as ips. I see that sound and vibe toolkit has the integration function but I am not sure I am properly using it. Do you know if there are any examples of how best to get displays in such units or writeups as to how to go about converting this to something along the lines of what suppliers and other vendors are displaying vibration data to us in? I haven't had as much time recently to work on this as desired but I also have to think I am not the first one to stumble on the need to do this considering how much vibration analysis in the USA uses such units.
Thanks,
Adam

ISO Human exposure vibration analysis

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