DAQmx Task name constant not recognized

[ciramjo]

I have created a Task (virtual channel list) using MAX and am trying to use a "Task Name Constant" to reference this task. However, when I run my vi, I get error -200088 "Task does not exist. When I showed this to my local field engineer, he created the attached vi that demonstrates the the problem in its simplest form, but could not offer a solution. When I use an express vi to create the channel list, my program runs without error.

[Laura F.]

Hello ciramjo,

I have taken a look at the VI you posted.  It seems you must be using some sort of SCXI setup.  I have simulated an SCXI chassis with an SCXI-1102 and run the VI with no errors.  After you have created the task in MAX, can you click on the "Test" button?  Do you get any errors when you do this?  When using the Task Name Constant, do you have to type in the task name, or does it show up in the drop down list?  What specific hardware are you using, what sort of task did you setup, and what version of NI-DAQmx are you using?  If you are not using the latest version of NI-DAQmx, 7.5, then I recommend that you upgrade.

Let us know the answers to these questions.

Thanks!

Laura

[ciramjo]

Hi Laura,

Thanks for your response. I think I stumbled upon the solution. I found that I have to the create task vi under advanced functions. then everything seems to work fine. I've posted the working code here. I searched this site and found that others have experienced the same the problem, so hopefully this will help them as well.

John

[Laura F.]

Hi John,

The DAQmx Create Task VI is actually  taking the task you have created in MAX, copying its settings and making a new identical task.  With that being said, you should not have to use this VI if you have already created a task and saved it.  I know that I do not need to use the Create Task VI if I have already saved my task in MAX.  If you look at your task "1104 Analog Signal" in MAX, can you click the "Save Task" button at the top of the screen?  If it is grayed out, the task is already saved.  Can you create a new task using different hardware to see if you have this same trouble?

Thanks,

Laura

[ciramjo]

Laura,

Apparently this is a known bug. Below is a response I got from another thread on this forum. Looks like I need to upgrade to Labview 7.1.1, but for now it's working fine.

Thanks for your help

John

Fateneh and John,

The KB found through the link below refers to the issue John is having with his code.

http://digital.ni.com/public.nsf/websearch/368AE98647EEE86E86256EBE0067B167?OpenDocument

I am not sure if this is the same problem you are having Fateneh.  When you create your code is the first function after your DAQmx Task constant a property node?  If not, this might not solve your problem.

The issue discussed in the KB above is fixed in LV 7.1.1, you might want to try upgrading your version of LabVIEW to fix the issue.

Fateneh, if this does not fix your problem, could you send me the code you created that does not work so I can take a look at it?

Thanks,
Lorne Hengst
Application Engineer
National Instruments

[Laura F.]

Hi John,

Thanks for letting me know.  It seems Lorne has found the solution to your problem.  I do run LabVIEW 7.1.1 so I did not see the error.

Good luck with your application!

Laura