DAQ Assistant

[Dejun]

Hello,

I am a beginner of LabVIEW. I am using PCI-6023E to do DAQ. I have a question on DAQmx task.

Method #1:
Start from DAQmx Task Name control and follow the step-by-step prompt, a DAQmx task will be generated, and this local task can be seen on MAX data neighborhood. Then I generate LabVIEW code. Using this method, the DAQ can be successfully implemented.

Method #2:
I directly place the DAQ Assistant Express VI on the block diagram, and use a graph indicator to show the data. This can achieve same purpose as method #1. However, I found no task is generated using method #2, which also can be reflected in MAX data neighborhood.

So, what's the difference between these two method? As I know task is integrated in DAQmx measurement, but why method #2 does not involve a task?

I am a newbie of labview, sorry for my simple question. Thank you very much for your answere.

Derek

[LA 75]

Hello Dejun,

That's actually a very good question. The difference between both methods is that with the DAQ Assistant you create what's called a Local Task that and with the DAQmx Task name you create what's called a Global Task. Global Tasks can be seen in MAX, Local Task's can; both will get you to the same result though.

Hope this helps.

Thanks,

LA

[LA 75]

[Correction to my last line]

...Global Tasks can be seen in MAX, Local Task's *can't*; both will get you to the same result though.

[Dejun]

Are you sure global is shown but local task not shown in MAX?

Then, why in MAX data neighborhood > Creat New > ..., there are two options: (1) NI-DAQmx task (2) NI-DAQ Global channel ?

[LA 75]

Hello Dejun,

That's correct...in MAX we have DAQmx Tasks and Global Channels. When you create a Task in MAX, you will create a local channel as well. When you create a global channel, you can add them into a Task. Local Channels are local to the Task, but global channels can be added to any task of the same type that you create.

Before we were talking about global/local Tasks...

For more information about this, I would encourage you to read the following KB:

http://ae.natinst.com/operations/ae/public.nsf/web/searchinternal/def7c64ffe5a525586256cc700762e4a?OpenDocument

Please let me know if you have any additional questions.

thanks,

LA