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Reference Number: AA-01651 // Views: 6 // Created: 2019-05-16 04:36:03 // Last Updated: 2021-12-08 18:48:07
HowTo
How To Export and Import IO Connections

As of RT-LAB version 11.3.4, there is a new Python API function that will allow you to export/import all the IO connections in your project using a CSV file. This How To guide will show you how to do this using the project IEC 61850 found in the example project directory.

This example project has 104 connections. If you were to reuse the Simulink model in another project, it would be time consuming to make each individual connection. The purpose of this new function is to automate that process.


Let’s start by creating a new project. We will call it exportConnections:


Once you click Next you can select from a list of template projects. Select the model IO > _Generic_ > IEC_61850, and then click finish.


As you can see from the Configuration, this project has 104 connections between the IEC 61850 IO Interface and the model.


Now to use the new Python API function, we need to create a script. This can be done in RT-LAB or by using an external interpreter. In RT-LAB, right-click on the project name and select New > File. Then name your file with the extension .py



Now the script will be open in the project explorer. To use this function, or any API call, a few things need to be in the script:

1. Import the RtlabAPI module so that you can access the API functions

2. Call the functions OpenProject (which takes the file path to the .llp project configuration file as input), and CloseProject to let the API connect and disconnect from the project. When you open a project with an API call, all the subsequent calls in that script will be performed on that project.

For an introduction on how to use the Python API, you can watch a tutorial video here: https://www.opal-rt.com/opal_tutorial/video-tutorial-1-test-automation-using-the-python-api/

After you have the basic structure in your script to use the RT-LAB API, you only need to use one function, ExportConnections(). This function needs one input, the file name of the CSV file that you want to create to write the IO connections to. 


Export Connections:

import RtlabApi

PROJECT = 'C:\\Users\USERNAME\\OPAL-RT\\RT-LABv202X.X2_Workspace\\PROJECT_NAME\\PROJECT_NAME.llp'

def Main():

    RtlabApi.OpenProject(PROJECT)

    RtlabApi.ExportConnections(filename='Connections.csv')

    RtlabApi.CloseProject()

if __name__ == "__main__": Main()


Import Connections:

import RtlabApi

PROJECT = 'C:\\Users\USERNAME\\OPAL-RT\\RT-LABv202X.X2_Workspace\\PROJECT_NAME\\PROJECT_NAME.llp'

def Main():

    RtlabApi.OpenProject(PROJECT)

    RtlabApi.ImportConnections(filename = None)

    RtlabApi.CloseProject()

if __name__ == "__main__": Main()


To run the script in RT-LAB, press Ctrl + F11. A new CSV file will appear in your project folder. As seen below, this file will be structured with columns that describe the connections in your project. The first column tells the connection type, this can be Model to IO, Model to Panel, or IO to Panel. The remaining columns describe details for Datapoints 1 and 2. You can edit this CSV file to add or remove connections or change the path if you change subsystems or the naming convention for example. 

Note: If you edit the file, be careful to ensure the accuracy of each entry, as a one character mistake will cause an error when you try to import it.


To demonstrate how to use this file, create a new project, and this time select an empty template.


With that new project open, right-click on models and select Import > Existing RT-LAB Model. 


Then choose the iec_61850.mdl model in the previous project you created. Make sure to only import the .mdl file so we have a clean start and don’t import the other project settings.


Now that you have the model in the same project, we need to compile the model. During the compilation process, RT-LAB will create a list of the signals and parameters in the model, which is needed to make the connections to. 

Since this example uses the IEC 61850 IO connections, we need to add that interface to the project. Select new I/O Interface here:



Then choose IEC 61850 from the list.

Note that in this example project, both the GOOSE Publishers and Subscribers have two messages, but the IO Interface only comes with one default. 


This is important to show because if the connections in the CSV file are not present in the project, both on the model, IO Connection, or Panel side, you will get an error when you run the script naming one specific connection that is missing, and this error will cause none of the connections to be made.

So we need to add a second message to both the Publisher and Subscriber. To do this, select the + button to add a message, then choose the icd61850.icd file.


After it is loaded, select the GOOSE ID, and choose the desired message:


Once you do this for both the Publisher and Subscriber, all the connections are now available in the project. Make sure to save the changes to the IEC 61850 IO Interface.

Now that your new project is set up, you can create a python script for this project, or can use the old one and change the path to the correct project:


Using the ImportConnections() function, you can either specify a file name, or set that variable to None. By setting the variable to None, when you run the script, a window will open allowing you to select the file from the previous project:


After you select the file, all the connections will be made to the script.