Sensitivity Units in Sound and Vibration Toolkits

[azri.azizan]

Greetings,

I acquired an impact hammer and downloaded sample vi that are made available by NI in the Sound and Vibration toolkit. However, there is no instruction on how to properly set up and use the vi.

Main question is, I would like to know how to set up channel type, range, sensitivity etc. Especially for sensitivity there is no 'unit' defined in the VI, is there any guideline provided by NI on how to set this up? Fyi, my impact hammer sensitivity is 1.1mV/N with measuring range of 5000N. Our accelerometer have the sensitivity of 1000mV/g with measuring range of 5g.

Attached are the pictures of the front panel and impact test template, zip files of vi and specifications of the impact hammer.

Looking forward for replies. 

  

[rwunderl]

The Context Help (Ctrl-H) reveals a clue when you hover over Sensitivity:

The Sensitivity is usually in some unit/EU (Engineering Unit). For accelerometers it's pretty much always mV/g.

So I'd set the Channel Type to Force (N) and the Sensitivity to 1100 (mV) for your hammer channel. Use the default 1000 for the accel and just pick whether you want the built-in excitation or not. Let me know if that works for you.

Also be generally aware that there are sometimes bugs in these shipping examples. I tried to use the Influence Coefficients one from the Sound & Vibration Toolkit, and it was littered with errors if you deviated from the default configuration (mostly due to incorrect unit conversions). Use it only as a starting point or a proof of concept for how to use the S&V functions, and not as a finished application.

[azri.azizan]

Dear rwunderl,

So if our hammer sensitivity is 1.1mV/N supposing I shall just input it as 1.1 in the vi? Correct me if I'm wrong.

Thanks for your reply.

[rwunderl]

Sure; I guess I wasn't focusing well at that moment. Give it a try!