LabVIEW Real-Time Module 2021 Known Issues

Überblick

This document contains the <product> <version> known issues that were discovered before and since the release of <product> <version>. Known issues are performance issues or technical bugs that NI has acknowledged exist within this version of the product.

 

Not every issue known to NI appears on this list; it is intended to show the most severe and common issues that you may encounter and provide workarounds when possible. Other technical issues that you may encounter could occur through normal product use or system compatibility issues. You may find more information on these issues in NI’s Product Documentation, Knowledgebase, or Community.

Bug Number

Legacy ID

Description

Details

60957 541200

Cursor Reference returned by the Cursor Move event not valid on LinuxRT x64 target with the Embedded UI enabled.

When obtaining the cursor reference returned by the cursor move event, the output is not valid on NI Linux Real-Time x64 targets with the Embedded UI enabled.

Workaround:

Obtain the reference from a graph control property node.

Reported Version:

LabVIEW Real-Time Module 2014 SP1

Resolved Version:

N/A

Added:

Mar 7, 2016

60958 543061

Error 56 Thrown When Using "Disconnect from Slave" Invoke Method

Using the "Disconnect from Slave" invoke method will almost immediately generate error 56; however the method functions correctly and disconnects the NI Real-Time system from the host machine.

Workaround:

Ignore error.

Reported Version:

LabVIEW Real-Time Module 2015

Resolved Version:

N/A

Added:

Mar 7, 2016

166718 654235

If 2 classes call separate instances of a polymorphic VI and an instance is included within the a class, the VI will break when compiled into an RTEXE.

A VI will break when compiled into an RTEXE if the VI contains multiple classes that call a polymorphic VI and the a copy of the polymorphic VI is in one of the classes.

Workaround:

Add the polymorphic VI to each instance of the class.

Reported Version:

LabVIEW Real-Time Module 2016

Resolved Version:

N/A

Added:

May 18, 2018

170895 514879

Running a VI Using Invoke Node Fails When Embedded UI is Enabled

When Embedded UI is enabled, using a LabVIEW Invoke Node to run a VI on NI Linux Real-Time results in an error about the Front Panel not being available. Using an Invoke Node to run a VI on NI Linux Real-Time works as expected if Embedded UI is disabled.

Workaround:

Instead of using an Invoke Node, use the Start Asynchronous Call with the connector pane of the target VI wired into the Open VI Ref.

Reported Version:

LabVIEW Real-Time Module

Resolved Version:

N/A

Added:

May 18, 2017

170896 580414

RT LEDs VI Returns Incorrect Error Code on Invalid Input

When selecting invalid parameter for a cRIO controller for the RT LED VI the error code and origin is incorrect. It should be error code one and the source should point to the RT LED.vi

Workaround:

There is currently no known workaround for this issue.

Reported Version:

LabVIEW Real-Time Module 2015

Resolved Version:

N/A

Added:

Mar 28, 2016

181570 720212

Calling the DAQmx Write VI after DAQmx Create Timing Source on NI Linux Real-Time can error depending on the DAQ hardware.

In NI Linux Real-Time, the DAQmx Commit occurs once the timing source is created. If a DAQmx Write is called after, hardware that does not support Non-Buffered HW-Timed Tasks can error.

Workaround:

Switch the two calls.

Reported Version:

LabVIEW Real-Time Module 2019

Resolved Version:

N/A

Added:

Apr 23, 2020

947407

Using Solve Linear Equations VI May Result in Wrong Values on NI Linux RT

On NI Linux RT, the underlying Singular Value Decomposition that is used in the Solve Linear Systems VI may produce an incorrect decomposition when the linear system has a large condition number or is rank deficient. The incorrect decomposition causes an incorrect linear system solution.

Workaround:

There is currently no known workaround for this issue.

Reported Version:

LabVIEW 2018 SP1 | LabVIEW 2019 SP1 | cRIO-9035 | cRIO-9068

Resolved Version:

N/A

Added:

Aug 12, 2021

968018

Running Application with PPL on Linux RT Can Crash with SIGSEGV

Interactively running an application on NI Linux RT that contains a Packed Project Library (PPL) sometimes crashes.

Workaround:

There is currently no known workaround for this issue.

Reported Version:

LabVIEW Real-Time Module 2019

Resolved Version:

N/A

Added:

Aug 12, 2021

1506353

NI Linux RT Controllers Have Less Free Disk Space after Installation than Was Available with Legacy Installation

Installing NI Linux RT may consume up to 200MB more disk space than a legacy installation, which is no longer available as of 2021. This may prevent successful upgrades of disk-intensive applications on CompactRIO, CompactDAQ, sbRIO, and myRIO controllers. Affected customers must continue to use legacy installation with LabVIEW Real-Time Module 2020 SP1 or earlier.

Workaround:

There is currently no known workaround for this issue.

Reported Version:

NI Linux RT 21.0

Resolved Version:

N/A

Added:

Aug 12, 2021

1628734

Refnums Can Become Invalid Erroneously

Refnums can become invalid unexpectedly during VI execution.

Workaround:

Add the token "UserDefinedRefObj.BinarySearch.LinearThreshhold=0" in the [LVRT] section of the lvrt.conf configuration file.

You can use the same token in the configuration file for LabVIEW or built applications.

Reported Version:

LabVIEW Real-Time Module: 2021

Resolved Version:

N/A

Added:

Nov 29, 2021

Final Time Issue Listed

Issues found in this section will not be listed in future known issues documents for this product.

Bug Number

Legacy ID

Description

Details

206134 700007

CPU load may be incorrectly reported when using Timed Loops on NI Linux Real-Time

In NI Linux Real-Time, the CPULoadTotal property node may incorrectly report the CPU Load when Timed Loops are used as part of the application.

Workaround:

There is currently no known workaround for this issue.

Reported Version:

LabVIEW Real-Time Module 2017

Resolved Version:

N/A

Added:

Apr 23, 2020

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Glossary of Terms

 

  • Bug ID - When an issue is reported to NI, you may be given this ID or find it on ni.com.  You may also find IDs posted by NI on the discussion forums or in KnowledgeBase articles.
  • Legacy ID – An older issue ID that refers to the same issue.  You may instead find this issue ID in older known issues documents.
  • Description - A few sentences which describe the problem. The brief description given does not necessarily describe the problem in full detail.
  • Workaround - Possible ways to work around the problem.
  • Reported Version - The earliest version in which the issue was reported.
  • Resolved Version - Version in which the issue was resolved or was no longer applicable. "N/A" indicates that the issue has not been resolved.
  • Date Added - The date the issue was added to the document (not the reported date).