Archived: LabVIEW 8.6 Control Design and Simulation Module Known Issues

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This document contains the LabVIEW 8.6 Control Design and Simulation Module known issues. It includes the set of known issues that were included in the LabVIEW 8.6 Control Design and Simulation Module readme as well as issues discovered since the release of the LabVIEW 8.6 Control Design and Simulation Module. Not every issue known to NI will appear on this list; it is intended to only show the severe and more common issues that can be encountered. Each issue appears as a row in the table and includes an issue title, a brief description of the problem, and any workarounds that might help resolve the issue.

The workarounds that appear in this document are not always tested by NI and are not guaranteed to resolve the issue. If a workaround refers you to the NI KnowledgeBase, refer to and enter that KB number in the search field to locate the specific document. The brief description given does not necessarily describe the problem in full detail, and it is expected that you might want more information on an issue. If you would like more information on an issue, feel free to contact NI and reference the ID number given in the document. You can contact us through any of the normal support channels including phone, email, or the discussion forums. Refer to to contact us. Also consider contacting us if you find a workaround for an issue that is not listed in the document so that we can add the workaround to the document.

Known Issues

The following items are known issues in the LabVIEW 8.6 Control Design and Simulation Module.

ID Known Issue
103270 Crash when deploying to NI CompactRIO device using RT desktop target
LabVIEW might crash when you deploy a simulation to a NI CompactRIO device using an RT desktop target. The RT desktop target is not intended for use with CompactRIO devices. If you want to deploy a simulation to a CompactRIO device, use the appropriate RT CompactRIO target.
100760 Mass compile simulation subsystems or Simulation Loops in build specifications
If you want to use a simulation subsystem or VI containing a Simulation Loop as a source file in a build specification, you first must mass compile or save the subsystem or VI in the current version of LabVIEW.
115644 Not all Microprocessor SKD example targets supported
You can use the Control Design and Simulation Module with only the following Microprocessor SDK example targets:
  • Windows Console
  • Unix Console
  • Axiom CMD565, eCos
VIs and Functions
Some VIs appear broken after mass compilation
If you mass compile the labview\vi.lib\addons\Control Design directory, the following VIs appear broken:

CD Discrete State-Space, CD Discrete Stochastic State-Space (External), CD Discrete Stochastic State-Space (Internal), CD Discrete Transfer Function, CD Discrete Zero-Pole-Gain, CD Predictive Observer, cd_Design PID for Discrete Systems (ZPK), CD Design PID for Discrete Systems, cd_Design PID for Discrete Systems (SS), CD Discrete State-space, CD Bode Graph, CD Nichols Graph, CD Nyquist Graph, CD Pole-Zero Map Graph, CD Root Locus Graph, CD Time Domain Simulation, CD SxZExternInnards.

These VIs are not actually broken.
114491 Discrete Linear Systems functions ignore skew parameter
The Discrete State-Space function, Discrete Transfer Function function, and Discrete Zero-Pole-Gain function ignore the skew parameter if you select Configuration Dialog Box from the Parameter source pull-down menu. Select Terminal from the Parameter source pull-down menu and wire a control to the skew terminal on the block diagram to modify the skew value.
39212 CD Canonical State-Space Realization VI does not support MIMO system models
The CD Canonical State-Space Realization VI works only with single-input single-output (SISO) system models. Therefore, if you wire a multiple-input multiple-output (MIMO) system model to this VI, the VI recognizes only the first (0th) element of this system model.

Workaround—Use the Array functions to index a MIMO system manually and send each element to this VI.
Display issues on Windows Vista
If you install the Control Design and Simulation Module on Microsoft Windows Vista and use a 120 DPI font setting, the configuration dialog boxes of the Simulation functions look incorrect. The front panels of some example VIs also look incorrect.

Workaround—These functions and VIs are not broken. However, you can use a different DPI setting to adjust the appearance.
49715 Creating subsystem from VI template results in broken VI
Creating a new simulation subsystem from a subsystem VI template results in a broken VI.

Workaround—Edit the VI and then recompile the VI. Compiling occurs when you create, save, or load a VI, and also at other times.
Express VIs on simulation diagram display incorrect font
Express VIs on the simulation diagram display execution status using the incorrect font size.
51203 VI executes extra minor time step
If you set up a VI to execute continuously with minor time steps, the VI executes an additional time after the last major time step.
49285 Compiling subsystem erases clipboard
Compiling a simulation subsystem erases the contents of the Windows clipboard.
Error reporting inconsistent based on feedthrough
Error reporting behaves differently depending on whether a function has direct or indirect feedthrough.
Improper feedthrough behavior inside Conditional Disable structure
Placing a Simulation function inside a Conditional Disable structure might cause the feedthrough behavior to work improperly.
Run button appears broken after recreating wire
Deleting and then recreating a wire might cause the Run button to appear broken.

Workaround—Click the Run button to run the VI.
VIs containing discrete Simulation functions appear broken
VIs that contain a discrete Simulation function and are saved in a previous version of the Simulation Module appear broken.

Workaround—Click the Run button to run the VI.
Build specifications fail
Build specifications fail unless all VIs are saved in the current version of LabVIEW.
Wires exiting Simulation Loop appear broken
Wires exiting the Simulation Loop might appear broken when you save or compile a VI.

Workaround—Move the mouse cursor over the wire.
48302 Broken Save and Load buttons
If you open the configuration dialog box of the State-Space, Transfer Function, Zero-Pole-Gain, Lookup Table 1D, or Lookup Table 2D functions and click the Cancel button, the Save and Load buttons might not work the next time you open the dialog box.
Sample skew parameter mishandles non-zero values
The sample skew parameter of the Discrete Linear Systems functions does not properly handle non-zero values. If you specify a non-zero sample skew value for a function, that function might have incorrect output for times between the initial simulation time and the time you specified for execution.
RT Communication Wizard does not work with stand-alone subsystems
The RT Communication Wizard does not work with stand-alone Simulation subsystems.
88068 Cannot undo changes in discrete rates
You cannot undo or redo changes in subVI discrete rates.
Resizing Simulation functions do not constrain icon proportions
Holding the <Shift> or <Ctrl> keys while resizing Simulation function icons does not constrain the proportions of the icon.
LabVIEW deletes undo information when creating a subsystem
Creating a simulation subsystem from a portion of a VI block diagram causes LabVIEW to delete all undo information. To undo creating the subsystem, you can copy the subsystem block diagram code, delete the subsystem icon from the VI block diagram, and paste the code back onto the VI block diagram.
Some instances of the Discrete Kalman Filter and Discrete Observer functions do not support deterministic real-time execution
If you specify Indirect feedthrough and the No Corr, w/ Check, No Corr, w/o Check, No Pred Gain, w/ Check, or Pred Gain, w/ Check instance, the Discrete Kalman Filter function does not support deterministic real-time execution.
If you specify Indirect feedthrough and the Current Observer, w/ Check or Predictive Observer, w/ Check instance, the Discrete Observer function does not support deterministic real-time execution.
Simulation Model Converter
Closing Simulation Model Converter returns error
After you close the Simulation Model Converter, the MATLAB® application software might display the following message: "Cannot close the model '<ModelName>' when it is being compiled or while the simulation is running". In this situation, enter the following command in the MATLAB® application software: <ModelName> ([],[],[],'term'), where <ModelName> is the name of the model you converted.
35496 Digital Clock block converts to continuous function
The Digital Clock block converts to the Get Simulation Time function, which executes continuously.
38076 Signals from S-Function block convert to vectors
Signals from the S-Function block always convert to a vector data type.
Must convert data types after model conversion
After you use convert a model, you might need to convert some data types. To convert from a double to a Boolean, insert a Not Equal to Zero? block. To convert from a Boolean to a double, insert a Boolean to (0, 1) block.
Currently Converting indicator includes time that Errors and Warnings dialog box is open
If you place a checkmark in the Show Errors checkbox and convert a model, the Currently Converting indicator includes the time for which you keep the Errors and Warnings dialog box open. If you do not want to include this time, place a checkmark in the Log Errors checkbox instead of the Show Errors checkbox.
Array indexes in converted models misaligned
Array indexes in array assignment and selector nodes might be off by one, because LabVIEW array indexes are zero-based.
Fcn block converts to MATLAB script node
The Fcn block converts to the MATLAB script node with only scalar double input terms.
37678 Product blocks in Matrix Multiply mode do not function correctly
Product blocks in Matrix Multiply mode do not function correctly. Try replacing the Product block with the A x B VI.
Scope block with multiple input signals only has first input connected
If the model you want to convert contains a Scope block with multiple input signals, the Simulation Model Converter connects only the first input to that block.
View button might not highlight corresponding node
The View button in the Errors and Warnings window might not highlight a corresponding node.
115677 (Linux) Cannot convert models containing Manual Switch block
You cannot convert models that contain a Manual Switch block.
Control Design MathScript Functions
LabVIEW MathScript functions take time to display results
Some LabVIEW MathScript functions display results in an external window. The first external window to appear takes a considerably longer time to display than subsequent windows.
89687 Cannot make root locus plots part of subplots
You cannot make root locus plots part of subplots.
Transfer function polynomial coefficients listed in descending order
In the LabVIEW MathScript environment, transfer function polynomial coefficients always are in descending order. However, the Control Design VIs assume these coefficients are in ascending order.
116020 Place and Find buttons broken for Implementation VIs and functions
In the LabVIEW Help, the Place on the block diagram and Find on the Functions palette buttons do not work for the Implementation VIs and functions.

MATLAB® is the registered trademark of The MathWorks, Inc.

Glossary of Terms


  • Bug ID - When an issue is reported to NI, you may be given this ID or find it on  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).