Multiple Executables Running For Control

[MSATLAB]

Hello,

     I currently have two executables running at the same time.  One is controlling a load bank and getting a ttl signal back from the load bank which is a warning light, while the other executable is just getting two signals from a drivestand.  I am using the same DAQ board and the same LabVIEW versions.  My DAQ board is PCIe-6259 and I am using LabVIEW Version 8.5.  I can start them both in any configuration and while I am running I can control the output signal from the DAQ to the load bank but I can not receive the Warning signal from the load bank.  The other executable works normally.  We have had some damage to equipment from this mishap.  Is there a reason why I only have partial control of one of the executables?  Or is this something that I should just not do? Or maybe this is just an error with LabVIEW?  If someone could help me as soon as possible I would greatly appreciate it. 

Michael B

[Wayne.C]

Michael,

Are you using DAQmx tasks in your vi's?  If so the two input tasks from the two vi's may not be getting along very well.  Are your vi's reporting any errors?  Should be able to verify by running both vi's together in development mode.

You might consider combining into one vi.

[Vanessa L]

Hi Michael,

It looks like you are able to control the load bank with an output signal from the card but not receive an input signal back from the load bank.  You mentioned that the warning signal from the load bank is a TTL signal.  Are you also using digital input channels for the two drivestand inputs?  As centerbolt said, if you are using two input tasks in the two separate executable files, there may be a conflict.  If the executable that is receiving two signals from a drivestand has already started the input task, the resource for this operation has been reserved on the board.  Then the other executable will not be able to access the input channels on the card to start its own task.  This KB, Causes of NI-DAQmx Error 50103 "The Specified Resource is Reserved" , explains this concept further .  If possible, the best solution would be combining everything into one VI and coupling all digital input channels into one task.  Hopefully this information is helpful!

[MSATLAB]

Hello,

     Thank you both for getting back to me so fast.  I am currently using a TTL signal reading into a analog input.  So all the inputs that I am using are analog.  I am not sure what you are really talking about concerning the DAQ task, so if you could delve into that deeper I think that it would help me out a tremendous amount.  I tried to run the two VI's with each corresponding project window open and was not able to click on the other one to even get it started while one of the was running.  So that possibility I am unsure about.  Thank you for the help again. 

Michael B

[Vanessa L]

Hi Michael,

Whether you are using analog or digital input channels, you should still couple all inputs into one task.  A DAQmx Task is a way to group and configure all channels at one time so that when the task is started in the program, all information needed has already been provided for the card.  Once a task starts, the resources  for those channel types are set and the card is communicating with the software according to the parameters that were configured in the task.  This link leads you to a video about creating DAQmx tasks.  It is part of the Getting Started with DAQmx Series that is posted on the website.  I would encourage you to look at this to learn more about tasks and why they are important.

In addition, I have a few more questions for you.  Is there a reason why you cannot combine both VIs into one as I mentioned before?  This would be the best option and the simplest solution. This will allow you to better control how you allocate your resources.  Are these executables that you are dealing with (.exe) or the actual Vis (.vi) that you can edit?  If both VIs are built in LabVIEW 8.5 you can simply highlight and copy the code from one VI to the other.  In order to combine everything together, you would need to have access to the VI files to edit.  Then you could rebuild that file into a single executable.  Please let me if this post helps you!