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ADC-11/10 with LabView - noise on input voltage

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ADC-11/10 with LabView - noise on input voltage

Postby Ian Joyner » Sat Apr 15, 2006 5:56 pm

Hi,

I have been using the example LabView VI to take readings from my parallel ADC-11/10. When reading from a stable voltage source at about 10 times per second, each reading varies by as much as 30mV. Appearing as noise when the values are plotted.

However looking at the reading from the same channel in PicoScope the voltage 'wobbles' no more than 1mV. I am sure the actual voltage is not changing at all as it is simply taken from a battery.

I also tried calling the adc11_get_value_and_time function from LabView. This showed similar noise and also appeared to be returning the 'value' parameter scaled to 4096 rather than 1024?

The 30mV noise is too much for my application, so any help with why it shows up in LabView but not PicoScope would be greatly appreciated. Thanks.

Ian Joyner
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Postby Michael » Tue Jun 06, 2006 8:20 am

Hello Ian,

Thank you for your post.

Can you elaborate on your setup here?

If you are running the ADC11 without any form of input, i.e. open ended inputs, then you will witness a quiescent signal from the A-D converter. This is quite normal and should disappear when you connect an input.

Both the 10 and 12bit versions return data in 12bit chunks so scaling will allways be to 4096 vertical steps.

Best regards,
Michael
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