continuous swept-sine measurement with usb daq

[titpoul]

Hello,

  is it possible to run a continuous swept sine measurement (SV example) on a USB 6218 daq? (after modification because the default configuration raises the error "Non-buffered hardware-timed operations are not supported for this device and Channel Type") I tried to change the output buffer size or to set Sample Timing Type to On Demand, but both raise other errors.

Guillaume

[JK1]

Hi,

Example finder lists the USB 6218 hardware for Continuous swept sine measurement which means that this HW supports this kind of measurment.  Have you tried normal measurements with the USB 6218? Is the error only for this kind of measurments or for all measurments?  How does the MAX respond to it?

Please post back if problem persists.

[titpoul]

Hi,

thanks for the help. For example of normal measurement, the stepped swept-sine example works well. The error is raised by the DAQmx Control Task commiting the AO task. I hope that answers your questions.

Best,

Guillaume

[titpoul]

Hello,

  are you able to reproduce the error I described?

Best,

Guillaume

[GarPar]

Hi Guillame-

     I tried to run this example program on a simulated USB-6218 and the program seemed to run fine with no errors.  Have you chosen the correct device (Dev1, Dev2, etc)?  You haven't changed any of the default settings, correct?

[titpoul]

I come back to confirm that there is no error when I try with a PCI 6225, whereas with a USB 6218 the error 201025 occurs at DAQmx Control Task.vi:1 "Non-buffered hardware-timed operations are not supported for this device and Channel Type".

The example VI is SVXMPL_Continuous Swept-Sine Measurements (DAQmx).vi, on LabVIEW 2009 with NI-DAQ 8.9.5.

[GarPar]

Hi titpoul-

     Here is a great KnowledgeBase article that discusses what is actually going on with the hardware.  Because these examples use a hardware-timed analog output task, they cannot be run on your USB device without modification.  The KnowledgeBase article discusses some options you have.  In the Example you are looking at, look in the svx_Commit Hardware Settings (DAQmx).vi.  On that block diagram, the svx_Configure (DAQmx).vi has all of the sample clock settings for the VI.  You may be able to play with those settings to avoid this error, but I am not sure that you will be able to get the example to run as expected.

     I have notified R&D that our example finder is erroneous in its indication that this example can be run on a USB DAQ device.

     I hope this helps.  Have a great day!