Migrating Simulation Interface Toolkit (SIT) Applications to the Model Interface Toolkit

Updated Dec 6, 2021

Reported In


  • LabVIEW Simulation Interface Toolkit
  • LabVIEW Model Interface Toolkit

Issue Details

NI discontinued the LabVIEW Simulation Interface Toolkit (SIT) and replaced it with the LabVIEW Model Interface Toolkit. What is the Model Interface Toolkit and how do I migrate my existing SIT application to it?


With the new Model Interface Toolkit, you can integrate models from a variety of simulation environments and programming languages. In addition to The MathWorks, Inc. Simulink® software, the Model Interface Toolkit supports C/C++, LabVIEW, and more than fifteen other environments. NI designed the toolkit with usability in mind, making every effort to provide easy-to-use APIs and new features, such as the ability to execute multiple models simultaneously.

Unfortunately, existing LabVIEW SIT code will not automatically update to use the new Model Interface Toolkit APIs. Refer to the following general guidelines for migrating SIT applications to the Model Interface Toolkit.

Migrating Models
After you install the Model Interface Toolkit, complete the following steps to prepare a Simulink model for use with the Model Interface Toolkit:

  1. In Simulink, replace any SIT input and output blocks in the model with NI VeriStand input and output blocks.

  2. Recompile the model according to the instructions in the Compiling a Model from The MathWorks, Inc. Simulink® Software - LabVIEW Model Interface Toolkit Help

Migrating LabVIEW Code
Identify the appropriate process for migrating a SIT application based on the features used to create the application in LabVIEW:

  • If you developed an SIT application using palette VIs the Simulation Interface Toolkit provided, you can replace many of the SIT VIs with Model Interface Toolkit VIs that provide similar functionality. For example, both toolkits provide VIs for initializing models, taking model time steps, and probing signals.

  • If you generated an SIT application, including host and driver VIs, using the SIT Connection Manager dialog box, you might need to rewrite the application because parts of the generated code do not correspond to Model Interface Toolkit VIs. If you cannot redevelop the application using the Model Interface Toolkit, NI will continue to offer support according to the guidelines found in the NI LabVIEW Life Cycle Policy , so you can continue to use LabVIEW SIT while you migrate your applications to the Model Interface Toolkit.

If you have any questions, please contact NI technical support.

Differences between the Model Interface Toolkit and Simulation Interface Toolkit

When you migrate an SIT application, note the following differences between the two toolkits


Behavior in SIT

Behavior in Model Interface Toolkit>

Resources in Model
Interface Toolkit Help

Development tasks

Generate host and driver VIs from a configuration tool.

Develop VIs that interface with a model using the Model Interface Toolkit API.

Basic Architecture for Executing Models

Supported models

Models from The MathWorks, Inc. Simulink software.

Simulink models, compiled LabVIEW VIs, models written in C, and several other environments that support compiling models to work with the NI VeriStand Model Framework.

Support for Model Types and Modeling Environments

Co-simulation with The MathWorks, Inc. software

The SIT application can interact with Simulink models as they execute in The Simulink, Inc. software on a Windows computer.

Not supported. You must compile Simulink models and run them directly on a Windows or RT target.

Compiling a Model from The MathWorks, Inc. Simulink Software

Host-target communication

The SIT Server uses a TCP/IP connection to transmit data between the host VI and the model.

Choose from several LabVIEW data communication methods, such as network streams, for implementing communication between the host and target that executes the model.


Supports executing multiple models?




Where to Go Next

Refer to the following resources to help you migrate SIT applications:

  • API Example Code—To browse example code that demonstrates various uses of the Model Interface API, select Help » Find Examples from LabVIEW to launch the NI Example Finder. Navigate to the Toolkits and Modules folder. To find the examples on disk, you also can browse to the <LabVIEW>\examples\Control and Simulation\Model Interface directory. You can copy and paste from one or more examples into a VI that you create.

  • Application Sample Projects—To see demonstrations of whole applications, refer to sample projects that LabVIEW and various LabVIEW add-ons provide. For example, in addition to controlling models, you might also need to transfer data between a host and execution target, integrate hardware I/O, and log data. To access these projects in LabVIEW, select File » Create Project to display the Create Project dialog box. You can modify the sample projects to fit your needs and add Model Interface Toolkit VIs at the desired locations. 

    The following sample projects might be relevant resources as you rewrite typical SIT applications:

    • Reading/Writing I/O—Refer to the Continuous Measurement and Logging sample project. This project uses the NI-DAQmx driver to acquire measurements continuously and logs them to disk.

    • Host-Target Data Communication and Logging—Refer to the LabVIEW Real-Time Control on CompactRIO (RIO Scan Interface) sample project. This project implements deterministic, software-based control of a plant. This sample project uses the RIO Scan Interface (RSI), which is an alternative to programming with the LabVIEW FPGA Module, to perform I/O on the FPGA. You also can refer to the developer walkthrough video.