Problem with NI USB 6009: DAQ Assistant Dev1 has to be changed to Dev2 sometimes

[johanneshoer]

I have a problem.

I use one NI USB 6009 device to read and write analgoue signals and in my VI I have place a DAQ Assistant block. Most of the time it runs well, but sometimes, probably after a reboot, I get a failure notice: something like "Error -200478 occurred at DAQmx Read (Analog 1D DBL NChan 1Samp).vi"

I found two workarounds:

First workaround: I place the DAQ Assistant again, then I have to configure the NI USB 6009 and all the I/Os again, it initialises and runs again for a while.

Second workaround: I open the DAQ Assistant Block and change all physical channels from Dev1 to Dev2 or the other way round (See attached picture). So sometimes it works with Dev1, sometimes with Dev2. I have no idea, why the physical channel changes and I haven't found a posibility to set the physical channel or the properties of the NI USB 6009 device.

The USB 6009 device is the only NI-device connected to the computer.

Please help me. How can I avoid that problem? The workarounds are not satisfying.

Win XP, LabVIEW 7.1  

Johannes

Message Edited by johanneshoer on 05-28-2009 10:43 AM

[RavensFan]

I would open up MAX and see what is the name assigned to the USB 6009.  Perhaps MAX is renaming it from Dev1 to Dev2 and back again between reboots.  I don't know why that would be.  You could go into MAX and rename the device whenever you see it change rather than making the changes in code.

Another possibility is to programmatically define the channels.  Search the forums.  I believe there are threads that discuss how to find out which devices are present in a system.  From discovering that, you could have the program decide whether to use Dev1 or Dev2

Message Edited by Ravens Fan on 05-28-2009 11:31 PM