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Troubleshooting Tips

Find Devices and Create a DataAcquisition Interface

Identify the devices you can access:

dev  = daqlist
dev = 

  9×5 table

      VendorID        DeviceID                             Description                                         Model                         DeviceInfo     
    _____________    ___________    ____________________________________________________    ________________________________________    ____________________

    "ni"             "Dev1"         "National Instruments(TM) USB-6211"                     "USB-6211"                                  [1×1 daq.DeviceInfo]
    "ni"             "Dev2"         "National Instruments(TM) USB-6218"                     "USB-6218"                                  [1×1 daq.DeviceInfo]
    "ni"             "Dev3"         "National Instruments(TM) USB-6255"                     "USB-6255"                                  [1×1 daq.DeviceInfo]
    "ni"             "Dev4"         "National Instruments(TM) USB-6509"                     "USB-6509"                                  [1×1 daq.DeviceInfo]
    "ni"             "PXI1Slot2"    "National Instruments(TM) PXIe-6341"                    "PXIe-6341"                                 [1×1 daq.DeviceInfo]
    "directsound"    "Audio0"       "DirectSound Primary Sound Capture Driver"              "Primary Sound Capture Driver"              [1×1 daq.DeviceInfo]
    "directsound"    "Audio1"       "DirectSound Headset Microphone (Plantronics BT600)"    "Headset Microphone (Plantronics BT600)"    [1×1 daq.DeviceInfo]
    "directsound"    "Audio2"       "DirectSound Primary Sound Driver"                      "Primary Sound Driver"                      [1×1 daq.DeviceInfo]
    "directsound"    "Audio3"       "DirectSound Headset Earphone (Plantronics BT600)"      "Headset Earphone (Plantronics BT600)"      [1×1 daq.DeviceInfo]

Create a DataAcquisition object for a specific vendor:

d = daq("ni")

For more information on the DataAcquisition interface, see The DataAcquisition Object.

To learn more about how to communicate with CompactDAQ devices, see Interface Workflow.

Is My NI-DAQ Driver Supported?

Data Acquisition Toolbox™ software is compatible with only specific versions of the NI-DAQ driver, and is not guaranteed to work with any other versions. For a list of the NI-DAQ driver versions that are compatible with Data Acquisition Toolbox software, see, and click the link for this vendor.

To see your installed driver version, type:

v = daqvendorlist
v =

  5×4 table

         ID                    FullName              AdaptorVersion      DriverVersion  
    _____________    ____________________________    ______________    _________________

    "ni"             {'National Instruments(TM)'}    "4.1 (R2020a)"    "18.5.0 NI-DAQmx"
    "adi"            {'Analog Devices Inc.'     }    "4.1 (R2020a)"    "1.0"            
    "directsound"    {'DirectSound'             }    "4.1 (R2020a)"    "n/a"            
    "digilent"       {'Digilent Inc.'           }    "4.1 (R2020a)"    "3.7.20"         
    "mcc"            {'Not Operational'         }    "4.1 (R2020a)"    "unknown"

If the version in the DriverVersion field does not match the minimum requirements specified on the product page on the MathWorks website, use the Add-On Manager to update your support package.

If your driver is incompatible with Data Acquisition Toolbox, verify that your hardware is functioning properly before updating drivers. If your hardware is not functioning properly, you are using unsupported drivers. For the latest NI-DAQ drivers, visit the National Instruments® website at

To find driver version in the National Instruments Measurement & Automation Explorer:

  1. Click Start > Programs > National Instruments > Measurement & Automation Explorer.

  2. Select Help > System Information.

Why Doesn’t My NI Hardware Work?

Use the Test Panel to troubleshoot your National Instruments hardware. The Test Panel allows you to test each subsystem supported by your device, and is installed as part of the NI-DAQmx driver software. Right-click the device in the Measurement & Automation Explorer and choose Test Panel.

For example, to verify that the analog input subsystem on your PCIe-6363 device is operating, connect a known signal (similar to the signal produced by a function generator) to one or more channels, using a screw terminal panel.

If the Test Panel does not provide you with the expected results for the subsystem, and you are sure that your test setup is configured correctly, then the hardware is not performing correctly.

For National Instruments hardware support, visit

Why Was My DataAcquisition Deleted?

An interface object can might silently be deleted while executing a background operation. This could be caused by the object going out of scope at the end of a MATLAB function, before the background task completes. To avoid this, insert a pause after starting the operation.

Cannot Find Hardware Vendor

If you try to get vendor information using daqvendorlist, and receive one of the following errors:

  • NI-DAQmx driver mismatch:

    Diagnostic Information from vendor: NI: There was a driver error while
    loading the MEX file to communicate with National Instruments hardware.
    It is possible that the NI-DAQmx driver is not installed or is older than
    the required minimum version of '8.7'.

    Install the NI-DAQmx driver of version specified in the error message.

    If you have a version of the NI-DAQmx driver already installed, update your installation to the minimum required version suggested in the error message.

  • No vendors found:

    No data acquisition vendors available.

    Reinstall Data Acquisition Toolbox software and applicable support packages.

  • Corrupted or missing toolbox components:

    Diagnostic Information from vendor: NI: The required MEX file to communicate
    with National Instruments hardware is not in the expected location.

    Reinstall Data Acquisition Toolbox software and applicable support packages.

    Diagnostic Information from vendor: NI: The required MEX file to communicate
    with National Instruments hardware exists but appears to be corrupt.

    Reinstall Data Acquisition Toolbox software and applicable support packages.

Cannot Find Devices

If you try to find information using daqlist and:

  • Do not see the expected device listed, refresh the toolbox, with


    If you still do not see the expected devices, go to the National Instruments Measurement & Automation Explorer (NI MAX) and examine the devices installed on your CompactDAQ chassis.

  • Receive one of the following errors

    • No data acquisition devices available.

      • Go to NI MAX and examine the devices installed on your CompactDAQ chassis.

      • If you cannot see your devices in NI MAX, check to see if you have turned on and connected your chassis.

      • If you have turned on and connected your chassis and issued daqreset, and you can see the devices in NI MAX, reinstall Data Acquisition Toolbox software.

    • The requested subsystem does not exist on this device.

      You could be:

  • If you are using NI 9402 with the counter/timer subsystem with the cDAQ-9172 chassis, plug the module into slots 5 or 6 only. If you plug the module into one of the other slots, it will not show any counter/timer subsystem.

  • If you are using an Ethernet or WiFi network CompactDAQ chassis, reserve the chassis in National Instruments Measurement & Automation Explorer (NI Max) first. Only one system can reserve this chassis at a time. For more information, see Why can't Data Acquisition Toolbox detect my NI DAQ devices connected through a cDAQ network chassis?.

What Is a Reserved Hardware Error?

If you receive the following error:

The hardware is reserved. If you are using it in another
object use the release function to unreserve the hardware. If you are using it in an
external program exit that program. Then try this operation again. 

Identify the DataAcquisition that is currently not using this device but has reserved it, and release the associated hardware resources. If the device is reserved by:

Another DataAcquisition in the current MATLAB® program.

Do one of the following:

  • Use release to release the device from the other DataAcquisition.

  • Delete the other DataAcquisition object.

Another DataAcquisition in a separate MATLAB program.

Do one of the following:

  • Use release to release the device from the other DataAcquisition.

  • Delete the other DataAcquisition object.

  • Exit the other MATLAB program.

Another application.

Exit the other application.

In these measures do not work, reset the device from NI MAX.


Your network device might also appear as unsupported in the device information if it is reserved or disconnected.

Network Device Appears Unsupported

  • If your network device appears as unsupported or unavailable, make sure that the device is connected and reserved in National Instruments Measurement and Automation Explorer. Use daqreset to reset devices settings.

  • If you see this timeout error when communicating with a network device:

    Network timeout error while communicating with device 'cDAQ9188-1595393Mod4'

    reconnect the device in National Instruments Measurement and Automation Explorer and execute daqreset in MATLAB to reset the devices settings.

ADC Overrun Error with External Clock

If you see this error when you synchronize acquisition using an external clock,

ADC Overrun Error: If you are using an external clock, make sure that 
the clock frequency matches scan rate. 
  • Check your external clock for the presence of noise or glitches.

  • Check the frequency of your external clock. Make sure that it matches the DataAcquisition Rate property value.

Cannot Add Clock Connection to PXI Devices

When you try to synchronize operations using a PXI 447x series device, you see this error:

"DSA device 'PXI1Slot2' does not support sample clock synchronization. Check device's user manual.

National Instruments DSA devices like the PXI 447x, do not support sample clock synchronization. You cannot synchronize these devices in the DataAcquisition interface using addclock.

Cannot Complete Long Foreground Acquisition

When you try to acquire data in the foreground for a long period, you might get an out-of-memory error. Switch to background acquisitions and process data as it is received or save the data to a file to mitigate this issue.

Cannot Use PXI 4461 and 4462 Together

You cannot use a PXI 4461 and a 4462 together for synchronization, when the PXI 4461 is in the timing slot of the chassis.

Cannot Get Correct Scan Rate with Digilent Devices

The scan rate of a Digilent device can be limited by the hardware buffer size. See Digilent Analog Discovery Hardware Limitations for more information on maximum and minimum allowable rates.

Cannot Simultaneously Acquire and Generate with myDAQ Devices

You cannot acquire and generate synchronous data using myDAQ devices because they do not share a hardware clock. If you have both input and output channels in a DataAcquisition, when you start it you achieve near-simultaneous acquisition and generation. See Automatic Synchronization for more information.

Simultaneous Analog Input and Output Not Synchronized Correctly

To simultaneously acquire and generate synchronized analog signals in the same DataAcquisition, try using an external trigger.

Counter Single Scan Returns NaN

An input single scan on counter input channels might return a NaN. If this occurs:

  • Make sure that the signal voltage complies with TTL voltage specifications.

  • Make sure that the channel frequency is within the specified frequency range.

External Clock Will Not Trigger Scan

Adding an external clock to your DataAcquisition might not trigger a scan unless you set the Rate property value to match the expected external clock frequency.

Why Does My S/PDIF Device Time Out?

S/PDIF audio ports appear in the device list even when you have no devices plugged in.

  • If you add this device (port) to your DataAcquisition and you have no device plugged into the port, the operation times out.

  • If you have a device plugged into the S/PDIF port, you may need to match the DataAcquisition rate to the device scan rate to get accurate readings. Refer to your device documentation for information.

MOTU Device Not Working Correctly

MOTU devices Ultralight-mk3 and Traveler-mk3 may not work with DirectSound and Data Acquisition Toolbox versions R2014a and R2014b. If you have these devices, specify the device to use stereo pairs:

  • In your MOTU Audio Console check "Use Stereo Pairs for Windows Audio" check box.

  • Specify desired sample rate in the Sample Rate field.