LabVIEW 8.2 Simulation Module Readme

August 2006

This file contains the following information about the LabVIEW 8.2 Simulation Module.

System Requirements

What's New in 8.2

Installation/Upgrading Instructions

Accessing the Help and Examples

Known Issues

System Requirements

• LabVIEW 8.2 Full or Professional Development System for Windows
• 250 MB additional available disk space

What's New in 8.2

The LabVIEW 8.2 Simulation Module incorporates the following new features:

Running Simulations on Embedded Devices

You can develop and execute simulations on an embedded device. To use this feature, you must install LabVIEW for the embedded device on which you want to run the simulation.

External Model Interface

You can define a dynamic system model in C++, compile this model to a dynamic linked library (DLL), and call this DLL from the LabVIEW simulation module. For examples that use this feature, refer to the labview\examples\simulation\External Model Interface\ directory.

VI / function behavior changes

• The Gain function has a new polymorphic instance, Dot product. Use this polymorphic instance to compute the dot product of two vectors.
• The Summation and Multiplication functions support mixed scalar/vector inputs.
• You can create polymorphic simulation subsystems.

Miscellaneous Changes and Updates

• The Configure Simulation Parameters dialog box has a new control, NaN/Inf Check. If you place a checkmark in this checkbox, the Simulation Module stops the simulation upon detecting a value of NaN or Inf.
• You can change the execution behavior of Express VIs and XNodes on the simulation diagram. To change this behavior, right-click these objects and select SubVI Node Setup from the shortcut menu.
• The behavior of the Auto Period checkbox in the Configure Simulation Parameters dialog box has been updated in the following ways:
  • You can use this option only with the internal 1 kHz and MHz timing sources. You cannot use this option with an external timing source.
  • After you place a checkmark in this checkbox, the Period text box displays the calculated period. The Simulation Module calculates this period by dividing the Step Size by the period of the timing source you specify. If this division is not even, the Period text box displays 0 and reports and error if you click the OK button.

Documentation Changes and Updates

• The PDF version of the LabVIEW Simulation Module User Manual has been deprecated. All help content is available as part of the LabVIEW Help. Refer to the Accessing the Help and Examples section of this document for information about accessing the help.
• The Simulation Module includes an introductory tutorial that shows you how to construct a simulation diagram. Access this tutorial by launching the LabVIEW Help, displaying the Contents tab, and selecting Simulation Module»Tutorial: Getting Started with the LabVIEW Simulation Module.
• Many new examples were added that demonstrate individual Simulation functions. These examples are located in the labview\examples\Simulation\Getting Started\ directory.

Installation/Upgrading Instructions

Complete the following steps to install the LabVIEW 8.2 Simulation Module.

1. Install LabVIEW 8.2 Full or Professional Development System.
2. Activate your copy of LabVIEW.
3. Launch LabVIEW at least once, then close the application.
4. Insert the LabVIEW 8.2 Simulation Module installation CD.
5. Run the setup.exe program.
6. Follow the instructions that appear on the screen.

Note: When loading simulation VIs saved in previous versions of LabVIEW, LabVIEW might search for .xnode files. Let the search run, and LabVIEW will find the files. After you save the VI in LabVIEW 8.2, this issue no longer occurs. You also can select Tools»Advanced»Mass Compile to update an entire directory of VIs to LabVIEW 8.2.

Accessing the Help and Examples

The LabVIEW Simulation Module Help contains conceptual, how-to, and reference information about the Simulation Module. Complete the following steps to access this help file.

1. Launch LabVIEW.
2. Select Help»Search the LabVIEW Help to launch the LabVIEW Help.
3. Click the Contents tab.
4. Navigate to the Simulation Module top-level topic.

The LabVIEW Simulation Module examples are located in the labview\examples\Simulation\ directory. You also can access these examples by launching LabVIEW and selecting Help»Find Examples.

Known Issues

The following list describes known issues with the LabVIEW 8.2 Simulation Module.

• When you launch LabVIEW after installing the Simulation Module, LabVIEW prompts you to mass compile some VIs. If you do not have the LabVIEW Control Design Toolkit installed, LabVIEW displays the following error messages:
  • Search failed to find "CD Pole-Zero Cancellation.vi"
  • Bad VI: "cd_D2C Everything Else from PFE .vi"
  • Bad subVI: "cd_Convert Discrete to Continuous TF.vi"
  • Bad VI: "cd_D2C Everything Else from PFE .vi"
  • Bad subVI: "cd_Convert Discrete to Continuous ZPK.vi"
  The Simulation Module does not use these VIs, so the absence of these VIs does not impact the Simulation Module.
• 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 the simulation diagram display execution status using the incorrect font size.
• 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.
• Compiling a simulation subsystem erases the contents of the Windows clipboard.
• Error reporting behaves differently depending on whether a function has direct or indirect feedthrough.
• Placing a Simulation function inside a Conditional Disable structure might cause the feedthrough behavior to work improperly.
• Deleting and then recreating a wire might cause the Run button to appear broken. Workaround: Click the Run button to run the VI.
• The states output of the Transfer Function function returns the states used internally to realize the continuous transfer function. The internal realization is in canonical form, and the states always initially start at 0.
• 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 unless all VIs are saved in the current version of LabVIEW.
• Wires exiting the Simulation Loop might appear broken when you save or compile a VI. Workaround: Move the mouse cursor over the wire.
• 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.
• 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.
• The RT Communication Wizard does not work with stand-alone Simulation subsystems.
• You cannot undo or redo changes in subVI discrete rates.
• Holding the <Shift> or <Ctrl> keys while resizing Simulation function icons does not constrain the proportions of the icon.
• You cannot place a LabVIEW MathScript Node inside a Simulation Loop.
• If you try and execute a hardware-timed application on an RTX target, LabVIEW displays the following two errors:
  • Simulation Loop: Code could not be generated correctly for this VI
  • Input Node: Not supported for current target
  This error means that RTX targets do not support hardware timing. Workaround: Place a checkmark in the Software Timing checkbox on the Timing Parameters page of the Configure Simulation Parameters dialog box. Access this dialog box by double-clicking the Input Node of the Simulation Loop. Refer to the Configuring the Timing of the Simulation Loop topic of the LabVIEW Help for information on using RTX targets.
• 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.

Simulation Translator

• The Simulation Translator does not correctly translate limits or values from the Slider Gain block.
• The Simulation Translator reverses terms from the Real-Imag to Complex block.
• After you close the Simulation Translator, 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 translated.
• Sum blocks with a single vector input are not translated properly.
• If the model has a 2D array going into a Widths block, the translated model returns a vector instead of a scalar. Each element of this vector is the width of one dimension of the 2D array.
• The Digital Clock block translates to the Get Simulation Time function, which executes continuously.
• Signals from the S-Function block always translate as a vector data type.
• The Simulation Translator incorrectly transposes 2D arrays from the Reshape block.
• After you translate 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.
• If you place a checkmark in the Show Errors checkbox and translate a model, the Currently Translating 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 formula and array assignment nodes might be off by one, because LabVIEW array indexes are zero-based.
• The Simulation Translator translates the MATLAB Fcn block as the MATLAB script node with only scalar double input terms.
• The Simulation Translator converts Manual Switch blocks with an array of control switches.
• Product blocks in Matrix Multiply mode do not function correctly. Try replacing the Product block with the A x B VI.
• If the model contains a Scope block with multiple input signals, the Simulation Translator connects only the first input to that block.
• The View button in the Errors and Warnings window might not highlight a corresponding node.
• The Cancel button in the Simulation Translator does not work while you are translating a model. Use this button to close and exit the dialog box.
• Multiple subsystems with identical names will be translated as a single subsystem VI.

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