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Changing AI range in the Multifucntion DAQ card while DAQ timed waveform is collected.

Hello Everyone,

 

I have a question regarding hardware timed anolog data aquisition using multifunctional DAQ card. For example USB-6229 card has AI ranges +-10, +-5, +-1, and +-.2V. I am collecting DAQ timed Finite or Continuous Waveform. Can I switch ranges in a fly while collecting between these ranges and if yes how? I know that using channel property the ranges can be switched when the task is not running but when the taks is running it does not allow me.

 

Thanks,

Ted

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@ttzvetkov wrote:

 

I know that using channel property the ranges can be switched when the task is not running but when the taks is running it does not allow me.

 


It seems you have answered your own question--you can't change the range setting on a channel while the task is running.  

 

You can however have multiple instances of the same physical channel in your task with each configured at a different range.  I'm not sure if this helps you or not...

 

AI_Multiple_Ranges.png

 

 

 

Best Regards,

John Passiak
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Hi John,

Yes I pretty much knew that. You have to stop the task to change the range.

The example you gave is very good for most of the cases with low scan rates. I use it sometimes when the sampling rate is not an issue. However when scanning 2 physical channels with 4 ranges you effectively read 8 times per point reducing the max sample rate perchannel 4 times. The dilema for me is to use external range selector or internal range selector. And it seems that everything is pointing to use the external range selection instead of have 3 extra readings per channel every time a point is read.

Thanks,

Ted

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