The following items are known issues in NI-DAQmx.
USB X Series Devices Do Not Work as SCXI Controllers in NI-DAQmx 17.6 and Later
The USB-6341, USB-6343, USB-6351, USB-6353, USB-6356, USB-6361, USB-6363, and USB-6366 are unable to be configured as a controller for SCXI devices in NI-DAQmx 17.6 and later. The USB-6346 and USB-6349 are unable to be configured as an SCXI controller in any release of NI-DAQmx.
NI PXIe-6386 and PXIe-6396 Potential Data Corruption in NI-DAQmx 19.0
With NI-DAQmx 19.0 and 19.1.0f2 firmware, if the Start Trigger (Analog Edge, Analog Window, Digital Edge, etc.) condition is met multiple times during the task, data corruption happens at each trigger condition after the first Start Trigger. Visit NI PXIe-6386 and NI PXIe-6396 Supplementary Information and Caveats for more information.
MAX Internal Warning when Upgrading to NI-DAQmx 18.0 or 18.1 with FieldDAQ
When a real or simulated FieldDAQ device is in the NI MAX database, upgrading from 17.6 or 18.0 to 18.0 or 18.1 will corrupt the NI MAX database.
To avoid this behavior, or for help recovering from the database corruption after encountering this issue, please refer to the following KB: Internal Warning when Upgrading to NI-DAQmx 18.0 or 18.1 with FieldDAQ.
DAQmx Read Returns Corrupt Data on Pharlap-Based LabVIEW RT cDAQ or PXI Controllers Under Specific Conditions
This issue happens only if the following is true:
- TDMS Logging for the task is enabled
Logging.SampsPerFile property is set to a non-zero value
- The TDMS filename contains an odd number of characters
If any of the above conditions are not true, there is no risk of data corruption. The issue has been traced back to the file system and a patch will be made available to LabVIEW RT users.
Upgrading Windows Results in Loss of Device Information
Upgrading the version of Windows on a system with NI-DAQmx installed can result in the loss of device names and device configuration. Devices can also appear disconnected. For information on how to resolve this, see Device Configuration Erased after Upgrade from Windows 8 to 8.1.
MAX Import Configuration Failure for C Series Devices
Importing a configuration in MAX generates an error if C Series modules have been removed from a CompactDAQ chassis. To fix the issue, either add the removed modules back into the chassis, or delete the removed modules from MAX and the
.txt configuration file.
NI Device Document Browser Unavailable
The Device Document Browser for NI-DAQmx is no longer available. To find documentation for devices supported in NI-DAQmx, visit ni.com/manuals.
Microsoft Silverlight Required for NI cDAQ-918x/919x Configuration
The NI cDAQ-918x/919x configuration, both with the NI Web-based configuration and in MAX, requires Microsoft Silverlight. Silverlight is installed with NI-DAQmx and is available from microsoft.com/silverlight.
NI cDAQ-918x/919x Works Incorrectly if Path Includes Non-ASCII (Multi-Byte) Characters
The NI cDAQ-918x/919x might not function correctly if NI-DAQmx is installed in a path with non-ASCII (or multi-byte) characters. This issue most commonly affects NI-DAQmx installations on Korean, Japanese, and Chinese versions of Windows. If your NI-DAQmx installation path contains non-ASCII characters, uninstall NI-DAQmx and other NI application development software and then reinstall your software to a path without non-ASCII characters.
Web-Based Configuration for the NI cDAQ-918x/919x Available Only for Windows and Macintosh
Web-based configuration is available for the NI cDAQ-918x/919x by accessing the device in a Microsoft Silverlight-enabled Web browser via its host name or IP address. This support is only accessible from Windows-based or Macintosh-based systems. Refer to the chassis user guide for more information.
Required Firmware Updates for Network DAQ Devices in NI-DAQmx
If you receive Error -201340, you need to update the firmware on your Network DAQ device. Firmware files for Network DAQ devices are named
ni<model number>fw.cfg (for instance,
ni9188fw.cfg). You can obtain the version of firmware supported by your version of NI-DAQmx by going to ni.com/info and entering the info code
exkpzt. If you installed NI-DAQmx from a DVD, you can also find a compatible version in the Firmware directory on that DVD.
New Error Returned when Loading an Invalid Device Name
In NI-DAQmx 9.3 and later, an invalid device name returns Error –200220,
kErrorInvalidDeviceID, instead of Error –200170,
kErrorPhysicalChanDoesNotExist. This change has no impact on newly created applications but can affect existing applications if the applications are performing error checking by looking for the specific error number (–200170).
NI USB-4431 Specifications Changes
The NI USB-4431 specifications have changed. The AO offset is specified with a higher level of uncertainty. The analog inputs and outputs also have a higher gain uncertainty than previously specified. In particular, sample rates of less than 40 kHz result in an accuracy drop. The newest version of the NI USB-443x Specifications reflects these changes. A separate document, Notice of Specification Change - USB 4431, details these changes as well.
Aborting Single-Point Reads and Writes in LabVIEW
Single-point reads and writes do not respond to the Abort Execution button in LabVIEW.
Configuring MAX Strain Tasks
MAX strain tasks do not support configuring terminal configurations. By default, the configuration in MAX is differential. For the NI SC-2043-SG, the terminal configuration is NRSE. To avoid configuration issues, use the NI-DAQmx API to create the task.
DAQ Assistant Maximum Channel Count
The maximum number of channels you can have in a task created with the DAQ Assistant is 4096 channels.
NI DAQCard-6715 Analog Output
Hardware-timed single-point mode and hardware-timed nonbuffered mode are nonfunctional. Your application is using hardware-timed nonbuffered mode if you have set up a sample clock and a buffer size of 0, or set up a sample clock, but do not begin writing until after you start the task. All other waveform and static analog output modes work as expected.
NI ENET/WLS-9215 Times Out Unexpectedly
On the NI ENET/WLS-9215, an unexpected timeout can occur in continuous tasks using an external or very slow sample clock. The last sample may not be returned until the next sample clock pulse. To avoid the timeout, increase the timeout time (to allow the next sample clock pulse to occur) or acquire an even number of samples.
Not all NI-DAQmx events will fire if the conditions for the event occur more quickly than the system can process.
Samples Not Acquired on NI 660x or NI 6624 Devices
When using pulse width, semi-period or two-edge separation buffered measurements with the NI 660x and NI 6624 on counters 0 and 1, some samples may not be acquired under certain circumstances.
Using Visual Studio C++, C#, Visual Basic .NET, and ANSI C Examples in Microsoft Windows 7/Vista
Running certain applications on Microsoft Windows 7/Vista requires administrator privileges, because the application name contains keywords such as setup, update, or install. To avoid this problem, you must add an additional manifest to the application that specifies the privileges required to run the application. Some NI-DAQmx ANSI C, Measurement Studio Visual C++, C#, and Visual Basic .NET examples include these keywords. Therefore, some examples for these application development environments include an additional manifest file that you must embed in the example executable.
In ANSI C, Measurement Studio Visual C++ , C#, and Visual Basic .NET, the manifest file is named
ExampleName is the NI-provided example name. The steps for embedding an example varies depending on the programming language. Refer to the comments included with affected examples for additional information.
Compiling Visual Studio 2005 examples can generate the following warning:
manifest authoring warning 81010002: Unrecognized Element "requestedPrivileges" in namespace "urn:schemas-microsoft-com:asm.v3". For more information, refer to the Microsoft Feedback web page. This warning does not affect example execution and can be ignored. This warning happens because of the version of
mt.exe that is shipped with Visual Studio 2005. The
mt.exe tool embeds the additional manifest in the example executable.
Important: Your computer may restart when you run an application that contains the additional manifest entry. Refer to the Microsoft Knowledge Base entry for more information. To avoid a computer restart, build your application using Visual Studio 2005 SP1.
National Instruments posts information about critical updates and security notifications on
ni.com/info and enter Info Code updates to access this information.
DAQmx Is Read or Write Late Obsoleted
The existing DAQmx Is Read or Write Late function/VI has been obsoleted and no longer has any effect. Applications that must check whether they are maintaining real-time behavior have two options. For the strictest checking, use the Wait for Next Sample Clock function/VI. Refer to your API reference help, such as the LabVIEW Help or the NI-DAQmx C Function Reference Help, for more information on this function/VI. To check only whether the application misses any analog input samples, set the Report Missed Samples property to True on the analog input task. In LabVIEW, the Report Missed Samples property is in the Real Time property node. For more details, National Instruments strongly recommends that you read the document referred to by the Wait for Next Sample Clock function/VI.
Duplicate Count Prevention Defaults
As of NI-DAQmx 7.4, the default setting for the duplicate count prevention attribute/property on M Series and TIO-based counters has been changed. This change affects all input counter operations, with the exception of single-point edge counting and position measurements. Duplicate count prevention is now on by default as long as the following conditions are met:
- The duplicate count prevention attribute/property has not been explicitly set.
- The selected counter timebase source is not set to an internal timebase.
- The prescaler attribute/property has not been set.
- The counter output event has not been configured.
To learn more, refer to Duplicate Count Prevention in the NI-DAQmx help.
Existing .NET Project Produces Build Errors
If you are using NI-DAQmx with a .NET language, an existing project can produce build errors from an assembly that is not referenced. To eliminate this error, add a reference to the NationalInstruments.Common assembly to the project.
Multichannel SCXI Convert Clock Default Rate Change in NI-DAQmx 8.5
Starting in NI-DAQmx 8.5, a delay of 20 µs was added to the fastest possible channel conversion rate on an SCXI chassis connected to a 16-bit or 18-bit E or M Series device. If a sample rate is set fast enough to require a convert clock rate greater than the default rate, warning
200011 is generated, informing the user that the accuracy of the measurement might be compromised. However, since this is a warning, the convert clock used is based on the rate needed by the sample clock set by the user (that is, convert clock = sample clock * number of channels).
For SCXI chassis containing a module with track-and-hold circuitry, 10 µs of padding is now added to the fastest possible conversion rate when connected to a 12-bit E Series device.
These changes ensure the most accurate data is being acquired. However, if the effect on the performance due to this change is too great (such as on an RT system using hardware-timed single point in a control loop), then the convert clock rate attribute can be explicitly set, overriding the default rate.
This change affects only multichannel acquisitions.
In versions prior to NI-DAQmx 8.5, only 10 µs of delay was added to the fastest possible channel conversion rate on an SCXI chassis without a track-and-hold module connected to any DAQ device. In these versions of NI-DAQmx, no warning was generated when the sample rate needed a faster convert clock than was chosen by default. When an SCXI chassis with a track-and-hold module was present, the convert clock rate selected was the fastest possible rate that the DAQ device can handle, up to 333 kHz.
NI PCI-6704 and PXI-6704 Current Output Accuracy
NI-DAQmx 8.3 changes the algorithm used to scale the 20 mA current outputs of the NI 6704 to a method that matches the behavior of Traditional NI-DAQ (Legacy). Previous versions of the NI-DAQmx driver use a second method.
The effect of the change is that when NI-DAQmx programs the 6704 to output current, the actual current level of the 6704 is 10 µA higher with NI-DAQmx 8.3 compared to previous versions of NI-DAQmx. The actual current output with NI-DAQmx 8.3 is the same compared to Traditional NI-DAQ (Legacy) drivers. This change has no effect on the voltage outputs of the 6704.
Because of this change, NI recommends that you externally calibrate NI 6704 devices with NI-DAQmx 8.3 (or later) before using devices with the NI-DAQmx 8.3 (or later) driver. NI 6704 devices that ship with NI-DAQmx 8.3 have already been calibrated with NI-DAQmx 8.3. For other NI 6704 devices, refer to the manual calibration procedure available at ni.com/calibration.
Unplug your USB-9xxx and plug it back in or power the USB device down and up after upgrading NI-DAQmx. If the USB-9xxx is connected to a USB hub, make sure to disconnect the USB-9xxx from the hub, not the hub from the computer. Disconnecting power from the USB device causes installed devices to load the correct version of the firmware.
Virtual TEDS Data for the USB-9233/9237
If you connect hardware TEDS to USB-9233/9237 channels configured with virtual TEDS, the virtual TEDS will be replaced with hardware TEDS data after upgrading to NI-DAQmx 8.6 or later.
SignalExpress 2012 is not supported in DAQmx 16.0, 16.0.1, or 16.1
The readmes for DAQmx 16.0, 16.0.1, and 16.1 incorrectly list support for SignalExpress 2012. Attempting to run SignalExpress 2012 with these versions of DAQmx will cause SignalExpress to crash upon opening. To resolve this issue, update to SignalExpress 2013 or later.