Building a LabVIEW User Interface for a Simulink Model with the LabVIEW Simulation Interface Toolkit

The Simulation Interface Toolkit (SIT) provides a seamless integration between The MathWorks Simulink software and LabVIEW. The Simulation Interface Toolkit automatically generates LabVIEW code to interface with a Simulink model resulting in a flexible and easy-to-use user interface. You first must configure the Simulink model to communicate with LabVIEW. Then you can create a LabVIEW host VI that automatically calls, runs, and interacts with the Simulink model.

Configuring the Simulink Model

1. Save the attached files, absbrakesingleclosed.mdl and abssingleclosed.vi, to the computer.
   
2. Launch MATLAB and notice how the MATLAB command window displays the following message:
   
   Starting the SIT Server on port 6011
   SIT Server started
   
   The Simulation Interface Toolkit automatically installs the SIT server. If you do not see this message. you have not installed the toolkit correctly.
   
3. Enter simulink in the MATLAB command window to launch the Simulink Library Browser window.
4. Select File»Open and select the absbrakesingleclosed.mdl, which is file you downloaded in Step 1, to open the ABS Braking model.
   
   The simulation model should look similar to the following diagram.
   
   
   This Simulink model represents an anti-lock braking system for a desired slip. The brake torque adjusts according to the current wheel speed and vehicle speed to achieve the desired slip.
5. At each point you want to monitor in the simulation model, add an NISink to the absbrakesingleclosed.mdl to allow LabVIEW to read the data at that point in the simulation model . In the Simulink Library Browser window, double-click the NI Toolkit Sinks library. Notice the NISink and NIXYGraph blocks.
6. Place an NISink block in the model window of the absbrakesingleclosed.mdl.
7. Connect the signal to the NISink block.
   The ABS Braking Model should look similar to the following diagram.
   
   
   
   You also can use the NIXYGraph block to plot and compare two signals in LabVIEW.
   
8. Save the Simulink model.

Creating a LabVIEW User Interface

1. Launch LabVIEW and open a new VI.
2. Select one slider control and three gauges and place them on the front panel.
3. Label the slider control Relative Slip.
4. Label the three gauges Wheel Speed, Vehicle Speed, and Brake Torque.
5. Change the Relative Slip scale to 0 to 0.3.
6. Change the Wheel Speed and Vehicle Speed scales to 0 to 100
7. Change the Brake Torque scale to be 0 to 1500.
   The front panel of the VI should look like the following front panel:
   
   
   
8. Save this VI as abssingleclosed.vi. Notice that there is no block diagram code for calling the Simulink model.

   Creating Connections between the LabVIEW User Interface and the Simulink Model
   

The Simulation Interface Toolkit enables LabVIEW to run and communicate with the Simulink model once you make the appropriate connections. MATLAB and Simulink must remain open to configure and run the simulation model.

1. On the front panel menu bar, select Tools»SIT Connection Manager to launch the SIT Connection Manager dialog box. Notice how the Controls and indicators listbox displays the controls and indicators you created on the front panel of the abssingleclosed VI.
2. Click the Load Model button to display the Select Host dialog box.
3. In the Select Host dialog box, make sure the Machine Name/IP is localhost.
4. Click the OK button.
By selecting localhost, LabVIEW connects to the SIT Server that MATLAB initially started. If you choose to start MATLAB on a separate computer with SIT 2.0 installed, you can connect to that computer by typing in the correct IP address.
5. In the Select Model dialog box, navigate to the folder where you saved the absbrakesingleclosed.mdl. Select the absbrakesingleclosed.mdl file and click the OK button.

Notice how all the parameters and sinks associated with the ABS Braking Model appears in the Model parameters and sinks listbox in the SIT Connection Manager dialog box.

6. To create a connection between the Brake Torque gauge in LabVIEW and the Brake Torque input in the Simulink model, select Brake Torque in the Controls and indicators listbox and select Brake»Brake in the Model parameters and sinks listbox.
7. Click the Add to Connections button to add the connection to the Current connections table.
8. Similarly, create the remaining connections between the LabVIEW controls and indicators and the Simulink parameters and sinks. The SIT Connection Manager dialog box should look similar to the following figure:


[+] Enlarge Image

Notice that the parameters and controls have a icon in front of them while sinks and indicators have a icon in front of them. Use these icons to ensure that you do not make an invalid connection.

9. Click the OK button.

Notice that the Simulation Interface Toolkit generates the block diagram code that governs the interaction between the LabVIEW front panel and the absbrakesingleclosed.mdl. The VI should look similar to the following figure:



10. Click the Run button, to run the VI. The Select Host dialog box appears.

11. Verify that the host computer is localhost. Click the OK button. Although the VI starts do run, the Simulink model is not running yet.

12. To run the Simulink model, absbrakesingleclosed.mdl, click the Run button, , on the front panel.
13. Adjust the values of the Relative Slip slider while the Simulink model is running. You can see the effect of relative slip on the wheel speed, vehicle speed, and brake torque.

The process described here does not require The MathWorks Real-Time Workshop. This VI uses Simulink to run the simulation. You also can use the Simulation Interface Toolkit together with Real-Time Workshop to build the model into a DLL for stand-alone simulation. You need MATLAB, Simulink, and Real-Time Workshop to build a model DLL and configure the user interface using the SIT Connection Manager dialog box. Once you create the model DLL and user interface, you need only LabVIEW to run the simulation. For hardware-in-the-loop (HIL) and prototyping applications, you can run the model DLL in LabVIEW Real-Time to provide real-time inputs and outputs and to ensure determinism.

Attachments

Downloads

abssingleclosed.vi

absbrakesingleclosed.mdl

28 ratings | 3.93 out of 5

Print

Reader Comments | Submit a comment »

Does Lab VIEW interface influence the simulation speed
I never used the LabVIEW interface for Simulink but, I would like to know whether it will influence the simulation time of Simulink model?
- Shivakanth Gutta, Shivakanth Gutta. shivakanth.gutta@gmail.com - Jun 2, 2008

This needs to be updated for SIT 4.0 (as does the User Manual).
- Peter POESEL, HTL HOLLABRUNN. p.poesel@utanet.at - Mar 24, 2008

Need to update
This needs to be updated for SIT 3.0 (as does the User Manual).
- Roderic Don, ATK Elkton LLC. roderic.don@atk.com - Feb 6, 2006