This question confused me

[snowgoose]

Greeting!
I found the following question and it really confused me, could anybody have a explain?
" How does changing a DAQ board from a 0-10 volt range to a -10 to 10 volt range, affect the minimum voltage change that can be detected?"
A. The minimum voltage change that can be detected will be depend inversely with the resolution of the board.
B. The minimum voltage change that can be detected will be split in half.
C. There will be no effct on the minimum voltage change that can be detected.
D. The minimum voltage change that can be detected will be doubled.


Another question about DAQ is :
When should tasks be used in a DAQmx application?
A. If you want to perform chanel acquisition in a distinct order.
B. if you want to sample channels with similar scaling
C. if you want to sample channels with similar timing and triggering
D. None of above.

Thanks for your answer.

[PauloM]

Hi,

I'm not very familiar wiht DAQmx, but the for the first question, think of it on the following way:
If you have a board with n resolution (8, 12, 16, 24, ...).
The minimum voltage change that you can detect is:
Voltage Range/2^n.
For instance, if you voltage range is 10V and your board is 12 bit, the minimum voltage change will be: 10/4096 = 2.4 mV.
So if you double your input range, the minimum voltage change will double too.
In the previous example, the minimum voltage change, if your range is 20 V will be 4.8 mV.

Hope this helps,
Paulo

[Tom_W_[DE]]

Hi snowgoose-

Rather than give you the answers to your assignment I will suggest some references instead.

Your first question relates to code width as described in this tutorial: Data Acquisition Fundamentals 

Your second question is addressed by the descriptions of DAQmx Tasks and Virtual/Global Channels in this article: Physical Channels, Virtual Channels, and Tasks in NI-DAQmx

Let us know if you have any additional questions.