vibration

[MWarlow]

Hi,

We currently use third party hardware for measuring vibration from accelerometers mounted to various parts of an aircraft engine. Because of the temperatures involved the electronics (conditioner) are not within the accelerometer but seperate and it also integrates the signal. Therefore by the time the third party hardware sees it or any NI instrumentation should we use them the signal is in v/ mm/s not v/g.

Is it simply best practice to have the signal in v/g or does it not really matter? We could buy different conditioners that dont integrate the signal for future projects but i would like to test the N.I Sound and Vibration measurement suite in an existing installation if possible. Basically the cost of the third party hardware is getting very expensive especially should we wish to plot water fall graphs etc  (tens of thousands), therefore im hoping i can simply feed the signal into an N.I card and use LabVIEW for the rest. The existing thrid party software works fine with the signal already integrated to v / mm/s so i assume LabVIEW can to?

We would be using the USB 9234 card for testing and wish to measure broadband vibration, vibration at specific frequencies and plot waterfall charts etc – and I would like to check if this is possible with the signal already integrated?

Does anyone here have enough knowledge to give us a quick LabVIEW diagram of what we would need to be doing in order to achieve this using a v / mm/s signal? And how it will be different  ( if at all )  to if the signal was coming in, in v/g

With the money involved, £2,500 for the suite  and then £1,000 for the USB card....plus upto £3,000 per PXI card thereafter (what we would be using in our installations rather than just testing) We would like to ensure that obviously we get this right.

Many thanks for any help you guys can offer

Regards

Mike Warlow

[preston_johnson]

Thank you for your post,

Getting started with the USB-9234 and the Sound and Vibration Measurement Suite is a great idea.  You may want to review these links...

Here is the user manual for the software

https://www.ni.com/docs/en-US/bundle/labview-sound-and-vibration-toolkit/page/svmain/svmain.html

You will also want to consider the use of the Sound and Vibration assistant which is included in the S&V measurement suite

Starting with NI vibration data acquisition hardware is also a great idea.  When you are ready to replace the signal conditioners, you can take advantage of the vibration sensor signal conditioning built into NI hardware:

NI-4472B

https://www.ni.com/en-us/support/model.pxi-4472b.html

If you have questions about the NI signal conditioning, please let us know.  We are eager to help.  

[DanBrowne]

Hi Mike,

I believe you also have a Support Request open with myself at NIUK Technical Support, I shall post the response I sent you below so others can also benefit:

From a hardware standpoint, either measurement is physically possible to acquire, as they are both voltages, which our hardware can acquire without any problems. However, from a software standpoint, the Sound & Vibration VIs are going to be expecting data in the format of some sort of acceleration value. If some of your data is in the format of v / mm/s, then in theory all that needs to be done is the reverse of the conversions made within the Sound & Vibration VIs when converting from acceleration to velocity and then to displacement, that being a simple differentiation of the v / mm/s signal.

One thing I would say is that if you are not that familar with the domain of Sound/Vibration measurement, it may be worth forwarding this information to your Vibration Measurement personnel, as whilst this differentiation to convert back to acceleration will work in theory, any offsets in the signal will be lost (from the nature of differentiation, ie: y=x^2+c differentiated is: y=2x)

Regards,

Dan - NIUK