simultaneous input output FRF measurment

[Rajavel]

Hi,

i need some help for measuring FRF. The setsup is shown in fig. For this purpose i have modified the SVXMPL_FRF(DAQmx).vi program. the reults i am getting is wrong. But i am not sure what is the mistake i am doing. It will be much appricated if some one who can help me abt what mistake i am doing..thank you..

I am using,

1.Lab view 10,

2. Sound and Vibration measurment suite 2010

3. USB carrier 9162 and USB 9233

Raja

[Jake_H]

Hi Raja,

Are you trying to figure out what the Frequency Response Function is or what the VI in your program is doing? If you need help with the VI functionality, you can use the Detailed Help section of Context Help (ctrl + h).

Also, you mentioned the results were wrong - what are you currently seeing and what are you expecting to see? Any more information you could provide about your application would be helpful.

[Rajavel]

Hi Jack, Thanks for the reply..

i am trying to figure out what the VI in my program doing...the result i am supposed to get is  the imaginary part of FRF should look like  "cotangent" curve but i am not getting..so, i just wish to know what the VI doing is correct...the test setup is simple and it's attched as Jpeg file in previous post..

Regards

Raja

[Jake_H]

Raja, 

I don't know much about your set-up, but i looks like you just have an analog voltage coming into your DAQ card. Assuming the data coming in is fine, what are you seeing after you manipulate the data and look at the FRF? I would recommend creating indicators or probing your data to see where the values are getting off from your expectations. If the inputs of your SVFA Frequency Response are OK, then look through the LabVIEW Help on that particular VI and see if it's doing what you think it should.