Is there a way to specify or built a low pass filter different than the build in filters in SCXI-1531?

[cdonmez]

I am making some vibration measurements using SCXI-1531 accelerometer input module. The built in analog low pass filters in the module do not suit to my frequency range. I am ending up reading much more data than  I need. I would like to learn, is there a way to specify or built a low pass filter with this module to have a low pass filter in the range of for example 500 Hz? Thanks for your time. Happy new year.

--Cemalettin

[preston_johnson]

I think you have two options,

1) use an external low pass hardware filter and place this between your sensor and your input on the 1531

2) use LabVIEW or software filtering to post filter the data.  Once you post filter the data, you can decimate or resample the data to a slower sampling rate and thus reduce your data.

Are you using LabVIEW?

[cdonmez]

Mr. Johnson,

Thank you very much for your reply. Do you have any external low pass filter hardware in mind? And yes I am using Labview 8.0. I hesitate to use soft low pass filter options due to my lack of knowledge about what is the best way to do it.

Sincerely.

--Cemalettin

[Chris_K_]

Hi Cemalettin,

National Instruments does not sell any individual hardware low pass filters.  Any filter that meets you application’s requirements should work fine.  I had a customer in the past, who was happy with the filter he bought from Kiwa Electronics.

I hope this helps

Chris_K_

[Neal M]

Hello Cemalettin,

I would just like to add my two cents on the topic.  There is an express VI called Filter in LabVIEW (except the Base version) that sets up a filter in software and is pretty easy to use.  It is in the Function Panel»Signal Processing»Waveform Conditioning palette.  When you put this down, you configure the filter type (lowpass/highpass/etc.), and the various specifications for the filter.  The only tricky part is the topology of the filter, but they are standard types and are well documented in the LabVIEW help file (search for the filter name). They can also easily be researched by searching the internet.

I'm interested with what you end up going with, please post back to let us know

[cdonmez]

Neal and Chris,

   Thanks a lot for your replies. I am planning to follow to soft filtering option first. Since I both needed to low pass the signal and decrease the number of samples, I will use both the low pass filter and the sample compression functions of the Labview. Lets see how this will shape the resulting waveform. I will inform you about the results.

Sincerely

--Cemalettin