How can I set the parameters of global channels and tasks previously created inside my application?

[Giovani]

Hi everyone !

Before proceeding to the description below I think it´s important to say that I´m using NI USB-6008 as DAQ device and the driver used is DAQmx 7.5.

I´m currently developing an application into which I intend to be able to have complete control of the DAQ device being used, i.e, I´ll be able to create, delete and change the configuration of global channels and tasks previously created, among other things.

To achieve the ends specified above I´ve already developed two vis, one to create global channels and the other to create tasks, and these two are doing a fine job. After this, I thought I came to the easy part ... I think I couldn´t be far for the truth! I thought that everything I should do was to specify which channel or task I´d like to configure and then use a property node to get the results I wanted, but it´s not working ...there are some DAQmx property nodes I thought I could use to do it  but I didn´t find a way to change the configuration of the global channels, and none of these property nodes seemed to work, i.e, although the simple vis used to test them ran the chosen parameters didn´t alter at all, after each execution I used MAX to see if they had changed, and to my chagrin they hadn´t.

Can anybody lend me a hand with this problem? As always, any help would be deeply appreciated !    

[Hal_L]

Hi Giovani,

There is a developer zone tutorial that discussus some advanced data acquisition features including programmatic saves of NI-DAQmx tasks, global channels, and scales.  This tutorial also includes an example program.

I wrote a short program that creates tasks in MAX. Whenever I wanted to change a part of the task, I would just change that feature in the example program. Take a look at the examples and please let me know if you have any further questions.

Regards,
Hal L.

[Giovani]

Hi Hal !

First of all, I´d like to thank you for posting a reply to my question. But, as I ´ve said before, the problem is not that I can´t create tasks and global channels - I´ve already developed two vis that do it -, it´s that I don´t find a way to change their configuration;  although I´ve made subvis using the ones available under the DAQmx palette, when they run then do without errors but nothing happens ...

I´ve already taken a look at the tutorial you mentioned, but it didn´t help ...

Thanks again for your reply!

[Hal_L]

Hi Giovani,

You can use property nodes to modify settings.  I created an example based off of an existing task and then modified some timing parameters. A key thing to note for this is that the "Overwrite Existing Task" option must be set to "True." Please take a look at the example and let me know if you have any further questions.

Regards,
Hal L.

[mission_labview]

Hi Dear

I had been thru all these problems .Well the solution to ur problem is that u might not be saving the tasks after making the changes .Do save the task (use Save task)after making the changes .I think it should work.Do let me know if u still have a problem.

Regards

[Giovani]

Thanks Hal L and mission_labview for your support ! I´ll follow your advice and see if it works and afterwards I´ll post a message here to let you know the results !