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Traditional DAQ locks PXI-6115 from access by DAQmx

After using a program that accesses a PXI-6115 using Traditional DAQ, LabView is closed. Then, a LabView program is used that accesses the same PXI-6115 using DAQmx. When trying to read from the device, LabView says the device is locked. The Measurements and Automation Tool was unable to unlock the device. The only solution to unlock the device was a system restart. Is there a way to avoid having to restart the computer?

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Message 1 of 5

This should not be the "normal way". Normally, closing the application which uses trad. DAQ for the 6115 should be sufficient to free the 6115. To be exact: A proper release of the DAQ device done by the driver.


This leaves me to a suspicion: Did the application using trad. DAQ crash or was it terminated unproperly (e.g. using the "Abort Button")?

If not, does the application clean up the DAQ reference properly?


hope this helps,


CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.
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Message 2 of 5

The application terminated properly, so the app probably does not cleanup the DAQ reference. If you have any suggestions on how to modify the program to do this, I would be happy to hear them.

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Message 3 of 5

Hi bcur,


Did you try this? (From the NI-DAQmx 9.2 Readme😞


After using a device in Traditional NI-DAQ (Legacy), you must reset the device before you can use that device in NI-DAQmx, or error code -200324 is returned. ... 

  • Call the Traditional NI-DAQ (Legacy) Device Reset VI or the Init_DA_Brds function
  • To reset devices in Traditional NI-DAQ (Legacy) from MAX, you must reset all devices at once. Right-click the Traditional NI-DAQ (Legacy) Devices folder in MAX and select Reset Driver for Traditional NI-DAQ (Legacy). For a remote RT target, you must use the Traditional NI-DAQ (Legacy) Device Reset VI.


Brad Keryan
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Message 4 of 5

I installed DAQmx 9.2.0 and reinstalled Traditional DAQ 7.4.4 and followed the proceedures mentioned above. In Measurment and Automation, the Traditional DAQ test panel was run for the PIX-6115. Then I clicked on the Traditional DAQ folder and reset the driver. The driver reset was said to be successful. However, when performing a self-test on the PXI-6115, the test failed because the device is reserved. The only way to unlock the device is to restart the computer.

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Message 5 of 5