accelerometer data acquisition

[dhkawasaka]

Hello,

I´m with some doubts in my accelerometer data acquisition and I´d like to share with the community

I'm using two PCB single axis accels and NI cDAQ-9178 with one NI-9234 module. Before acquiring some data, I have checked my accels with my handheld shaker and it worked good.

When I start acquiring, most of my data looks fine, but in some instances I am getting some strange data. I have cutted and attached some parts that it happened.

I cannot understand where this distortion is coming from - I have checked connections and cables, but they´re good.

Does anybody know what is going on? Does it really happens with my accels?

Thanks

[Henrik_Volkers]

Please Post a .png picture of it.

Posting the data is Perfect for analyses but currently I'm with this mobile stuff

[dhkawasaka]

Hello Henrik,

Thanks for the insterested. Please find attached the picture.

regards,

[Henrik_Volkers]

If you have short loose contacts, thats the signal you get with IEPEs.

[dhkawasaka]

Hello Henrik,

I´ve checked my contacts and everything looks good.

I´ve done one test that during an acquisition, I´ve shaked the cables close to my data acquisition but nothing happens.

Another test that I´ve done was simulate a hit. I´ve got one plate and installed my accelerometer, them I hit it twice with two different strengh. I´ve repeated the process and the results were all the same - when I hit it harder the same phenomenom happens in my signal.

My rack is cdaq-9178 with one module NI9234. Can you simulate it?

[Henrik_Volkers]

Sorry for the late reply,

I still vote for loose contacts, but there is an other mechanism that migth cause that signal.

Do you have any switched power controllers nearby?  (Motor controller, not so well shielded/filtered class D amplifier?)

[Ian_Ren]

If not the connection issue, another possibility is that the IEPE accel is overloaded. What is the range (or model #) of the PCB accel?