DAQ assistant

[Clint1000]

I created a 3  voltagechannels using DAQ Assistant in PXI "1".  I then moved my controller to another PXI chassis PXI "2"..did some Labview coding.  When I moved my controller back to PXI chassis #1 Labview ( DAQ Assit)  says it can't find the DAQ Card.  I didn't move the DAQ card in PXI #1.  It shows up fine in MAX.  How does DAQ Assit. find the DAQ Card?

[GerdW]

Hi Clint,

those ExpressVIs are fine when you want to have a quick&simple (aka "dumb") solution.

When you need more specific jobs you should use the DAQmx functions.

They are easy to use and well-explained in all those example VIs coming with LabVIEW/DAQmx!

How does DAQ Assit. find the DAQ Card?

Well, you could open the front panel of the DAQAssistent to see how it is coded inside…

Or use DAQmx functions to detect the installed DAQmx hardware!

[Clint1000]

Sorry, maybe I should have been more specific in my question.

I've used DAQ mx for years and was just trying to follow an example a previous developer had used when he coded his vis using DAQ Assitant.  My controller (8101) was used in chassis#1 w a 6229 in say slot 3.  I developed LV code using DAQ Assit.  DAQ Asst measured ch voltages.  I then moved my controller to chassis 2 w a different 6229 in say slot 4.  I developed LV code.  The controller was then moved back to chassis 1.  6229 still in slot 2.  When I open the properites of the DAQ Asst for the voltages measurements the 6229 is missing.  Its there in MAX. I think its because I move the controller from one chassis to another and the DAQ card (6229) was in different slots.   Is there a way to "relink" the daq back to the original DAQ Asst or do I have to go thru and recreate everywhere I used DAQ asst?

Thanks..

[crossrulz · Accepted solution]

If things change (like a DAQ that was being used is now gone), the DAQ Assistant complains.  You will have fix them all.  If you use the actual DAQmx API, you just have to make sure the cards are named correctly in MAX.  Or I use a configuration file for setting up my tasks.  So if something changes, I just have to update that configuration file (or just fix the names in MAX).

[Blokk]

You could program your application in a way that it has an initalisation step where the user can discover connected DAQmx hardware, and assign plus dynamically create the required tasks...

Here is how you can dynamically discover connected DAQmx hardware, and get their name:

http://digital.ni.com/public.nsf/allkb/835D17D9681A42808625754500080FFF

[Clint1000]

Thanks..thats what I ended up doing.  "FIND"ing all DAQ Assistant calls and re mapping them to the DAQ Card that I was using.  I was just curious why:

the daq assistant had the same name from vi to vi yet when i re linked the card in 1 vi it didn't relink it in another.  I had to open ALL 40 calls to the vi and do it manually.  Lesson learned.

[RavensFan]

They might have the same name, but they are actually 40 different subVI's.  (Technically not a subVI, but effectively a subVI because there is underlying code behind each instance of that express VI.)