Global channel

[TonY_20]

Hello,

in MAX i've created some global channel (linked to a PCI-6229 multifonction card), in my program i call directly these global channel on reading or writing (depends of the type of channel).

This works fine until a big error appears, i've not made any change in the program and i get this error "the task doesn't exist" although it worked previously.

I noticed that it doesn't work only for the digital output while for the rest (analog input, output...) it always works.

In MAX the global channel works fine also. It's only when i use the global channel in labview on a digital output that i get this error.

I've tried to repair MAX, DAQmx, but the error is still remaining... i don't understand why....

The only issue that i've found is to declare a Task containing only this channel, and call the task in Labview for working fine.

Somebody know this problem? Can't use global channel only on digital output although it worked fine previously...

Thanks for any help,

Tony

[MickeyD]

Hi Tony,

I want to clarify the issue.  You can make a global channel for a digital output and then if you were to use that channel in LabVIEW you will get the error?  It sounds like the global channel is not saved.  The error message they give you should have a code associated wtih it.  It often helps in solving these problems to post that code.  If it is code 200044, then I would refer you to the following knowledge base.  Why Do Global Digital Channels Cause Error 200044 When Loaded In Daqmx Task?
If the code is something else please let me know and I will stay on top of this issue and help you get it resolved.

Have a great day,

Michael Denton
Applications Engineering
National Instruments

[TonY_20]

Hi Mickey,

"You can make a global channel for a digital output and then if you were to use that channel in LabVIEW you will get the error?  It sounds like the global channel is not saved."

The global channel is saved, it worked for a long time in Labview, but now i get in Labview the error 200044 that says "task/channel doesn't exist", and in MAX this global channel works fine... And more, this error happens only for all global channel of digital output type...

[MickeyD]

Hi,

I recreated the issue from the above KB, but from your post that does not seem to be the issue you are seeing.  Did you change anything on the system?  Install a new piece of hardware upgrad drivers.  Something obviously has changed in the way that task exists in LabVIEWS eyes. 

If you place that channel in a new Task in LabVIEW, then it works fine?  It is only saved LabVIEW code that runs that channel that causes the problem?  Any information relating to what you did before noticing this change in behavior would be helpful?  Did you go back and change the channel in anyway?  I know it is just a single Digital channel.  I am looking for a possible cause of this, but the only documentation I have found so far is the above KB.  I will get back to you know when I have more information about the issue.

Have a great day,

Michael Denton
Applications Engineering
National Instruments