Data Collection Using cDAQ-9174

[202108594@post.au.dk]

Hi

Iam currently usin the NI cDAQ-9174 (an older version it seems) to collect some data using both vibration and audio sensors. To insert my sensors I use the two NI 9232 with BNC which each have 3 channels. Do you know if the channel have any crosstalk and also do you know if the system can messaure the frequency from the power-grids?

Iam messauring vibrations using the NI MAX program where the unit is in volts but regardless of me putting the sensor on the ground or on a machine with fx 50 Hz I get spikes in the fft domain, at 50 Hz. The grid where I take my messaurments provide a frequency of 50 Hz, but I would still assume that there should be a difference when plotting - but there is not..

Iam I just using the hardware wrong or have you heard of this before?

Kind regards

Lukas

[santo_13]

NI-9232 is the right choice for sound and vibration measurements.

The cables are expected to pick up mains frequency interference in the signal if not properly shielded.

What do you mean by "I would still assume that there should be a difference when plotting - but there is not."?

[202108594@post.au.dk]

Thanks for the answer and sorry for the confussion!

What I mean is that when holding a sensor by hand and I plot what I get it look very very close to the data plottet when the sensor is on the machine. Which to me is weird since I would expect a different reading of the data when the sensor is on the machine.

Kind regards 

Lukas 

[santo_13]

You can use the DSA soft front panel to test the data to check if your code is not the culprit.

https://forums.ni.com/t5/NI-Labs-Toolkits/Dynamic-Signal-Analysis-HW-Soft-Front-Panels/ta-p/3497079

[202108594@post.au.dk]

Thank you very much! 

I will try using the DSA software.

Kind regards

Lukas