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How to change Resolution of ADC

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Hi,

 

how can i change the resolution of the analog-digital converter on my NI-USB6211 from 16bit to 12bit ?

This should happen in Matlab. I'm using the Session based interface.

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Why would you want to?  I don't see what you would be gaining by doing that.


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To change resolution, you would need to change the DAQ device to one that has 12 bits. Silly question as far as I can see.
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It's because of a Matlab script whitch ran with an older daq pad with a 12 bit resolution.

I have to migrate it to a newer daq pad and had also to rewrite parts of it as i needed a new interface in Matlab (session based interface as legacy based interfaced is no longer supported.

Here is a screenshot of a Voltage measurement. The blue curve is from the new daq pad and looks quite erratic. I think the reason might be the adc.

Maybe you have some ideas

 

Voltage

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This doesn't look like an ADC issue.  It looks more like a noise issue.  What are you trying to measure?  What is your sample rate?  Do you have things properly grounded?


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I want to measure the voltage of a window motor.
I tried different sample rates, but they all look similar to the screenshot i posted. There the sample rate is 10k S/s.

I hope the everything is properly grounded

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Try a smoothing algorithm. You can do it yourself, use a low pass filter, or use Savitsky-Golay smoothing.

 

If you read the raw binary from the DAQ device, you could manipulate the bits to eliminate the 4 LSB.

 

Lynn

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Solution
Accepted by topic author mertin

I got the solution:
Changed the ADC range from -10 V - 10 V to -.0,2 V - 0,2 V

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