best precision with NI9207 with multichannel acquisition

[fabiano_@_maxwell]

Hello,

I'm trying to acquire voltage signal on multiple channel with NI9207. For my application it's not so important time relationship between channel; instead it's very important precision.

In order to achive the best precision there is differece between reading a single sample channel by channel or reading a block of samples on a channel, moving on another channel, read another block of samples and so on..?

And again: when I create Virtual Channel by "DAQmx Create Virtual.vi" giving it the range of channels to acquire (let's say Dev1/ai0:Dev1/ai4) how can I control this aspect?

Thanks in advance

Fabiano

[bronzacuerta]

Hi Fabiano

using NI 9207 you can set conversion type in HighSpeed mode or HighPrecision mode.

<C:\Program Files (x86)\National Instruments\LabVIEW 2012\examples\CompactRIO\Module Specific\NI 9207\NI 9207 Getting Started\NI 9207 Getting Started (Host).vi> is a good start point.

The way you read samples (on demand, finite samples, continuos samples) does not interfere with precision.

In general the way to achive maximum precision is to exploit all the ADC input range.

Referring to

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And again: when I create Virtual Channel by "DAQmx Create Virtual.vi" giving it the range of channels to acquire (let's say Dev1/ai0ev1/ai4) how can I control this aspect?  

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if your intention is to manage more then one physical channel in the same task, you can write Dev1/ai0:4 as physical channel input in DAQmx Create Virtual Channel.vi or you can arrange a cascade connection of more than one DAQmx Create Virtual Channel.vi each one with only one physical channel.