Signal Conditioning

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NI 9237

Hi

We are developing a small equipment using a force transducer. This is connected to NI9237 module.

We experience noise and a fluctuating signal (wavy). In the pdf manual analog and digital filtering is mentioned. We are little unsure if we can adjust these filters, or filtering is automatic connected to the data rate?

Thanks, in advance.

 

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According to this manual

https://www.ni.com/pdf/manuals/374186a_02.pdf

(pages 7 and 😎 The filtering is automatically linked to the data rate and looks like it's designed to prevent aliasing. What is your data rate?

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I usually go this way:

 

First: Know your enemy . Do some measurements with the highest possible samplerate.

Analyse the data: How does it look in the frequency domain? (Have a look at the power spectrum)

Is there power line hum? Or other noise maybe from switched power units/engines ?

Spikes? 

 

What could be the sources of the unwanted/unexpected? Is it possible to reduce it by design? (cable, shielding, vibration, EMC? ...)

 

Next: what is the signal (bandwidth) I want to look at?  A filter (analog or digital) can cut unwanted signals .

Rule of thumb: A lowpass filter always help. A lower low pass filter help more 😄   

(If you have a strain gage, try a 470nF (more (2µF) or less (100nF)... ) capacitor in the sense line)

 

If you post some sample data (not pictures) , a vi containing a graph with data (make current values default) , tdms, wfrm ...

(at least some periodes of your wavy signal 🙂 ) and tell the needed bandwidth, a better hint is possible.

 

 

 

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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Thank you,

 

 

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