USB Carrier loader problem

[GE_Osmonics]

Hello:

Have (2) USB devices each configured as a separate tasks that are both sampled
every 1 sec. inside a single while loop.

Occasionally my PC will lock up.  If look into the administrative tools event
viewer system log it report that the problem was "The NI-USB 9162 Carrier
Loader Driver service failed to start due the following error:
The service cannot be started either because it is disabled or because it has
no enabled devices associated with it".

This has become a real killer since it takes down other non LabVIEW applications
resulting in lost test data.

Any ideas as to what I can try?

Thank You!

[Nicholas_B]

Hi GE,

Try inserting a Wait function inside your while loop to supply a small execution timing delay to free up your processor.  5-10ms should be fine.  Also, does your code run properly if you only read from one device/task instead of both at the same time?

Feel free to attach your code and a screenshot or exported list from the Event Viewer. 

Regards,

Nicholas B, National Instruments

[GE_Osmonics]

Hello:

Here is a copy of my USB code.  (2) USB task running in a while loop being updated every 1 sec.

I failed to mention that the USB code is complied and is launched after a another complied VI is launched first.

The other compiled application makes use of PCI DIO-96 cards and has been trouble free for 1.5 years

The PC is an AMD Athlon XP-3200+ 2.20 GZ with 448 MB RAM running windows XP.  Also the attached Printer is a USB device.

Hope this helps.

[GE_Osmonics]

Hello:

Setting computer to avoid sleep mode correct computer lock up problem.

But my Temperature plots still go to 25C for some unknow reason for 1 sample period only when a second compiled LabVIEW application is running at the same time with the Temperature plot program.  This same program is run on another computer and has the same plotting problem when run at the same time with a second compiled VI.

[Nicholas_B]

Hi GE,

After looking at the code, it seems like the problem could be coming from the fact that you have several while loops embedded inside each other, and one that is software-timed.  One test I would recommend is to set up a very simple DAQ VI that just reads the value of the temperature in a while loop.  We have many examples in the Example Finder that you could run as-is.  Try performing this simple DAQ while the other compiled VI is running and see if that changes the results. 

Regards,

Nicholas B, National Instruments

[Chris_Co]

Hello GE,

When you have multiple while loops embedded inside one another, Each loop should have a wait command ( 1 millisecond at least).  And careful consideration on the amount to wait.  The innermost loop would have the shortest wait ( the amount depends on all loops execution rates).  Applying the wrong wait times can get you into trouble fast with you current structure.  For instance in your code, the first case structure (the one that is dependant on start, exit, print and default) the default, and print cases do not have a wait timer in them, which basically means literally no other running program has a chance to do much.

Another tip would be to log your data to the hard drive during the entire test so no data is lost.

Also, I would think you would wait for all of the hot/cold booleens to be true to grab the calib temp for its respective range.  Right now the program applies the calib temp if the first hot/cold booleen is true and in range. but then again i do not know what you are trying to achieve.

I hope this helps you.

Chris Co

PS.  I personally would abondon the multiple while loop structure and rewire it to either an event or single loop structure, well any other will do.

Message Edited by Chris Co on 02-07-2007 08:15 PM

[GE_Osmonics]

Hello:

Yet another PC has a problem with my application.  This one runs an PCI 6503 card compilied VI.

Hope this helps!