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v10.0.1.x for R2026a
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IO131 - Analog Loopback

This example demonstrates a simple communication between the two Analog inputs and outputs present on the IO131 I/O module, without using DMA (Direct Memory Access).
The IO131 is a fast, simultaneous-sampling, 16-bit analog input and output module, complete with dedicated Simulink® driver blocks.
Table of Contents
Setup Prerequisites Test Setup Initialize and Open the Simulink model Model Description Build, Download, and Run the Example Check the Results Additional References

Setup

Prerequisites

You will require the following to run this example:
  • Speedgoat real-time target machine with one IO131 I/O module installed
  • Connector cable from the I/O module to the terminal board
  • 50-pin terminal board with jumper wires

Test Setup

On the terminal board of the analog I/O module, connect the positive (+) pins of the Analog Inputs 1 and 2 to the pins of Analog Outputs 1 and 2, and connect the negative (-) pins of Analog Inputs 1 and 2 to GND.
IO131_AnalogLoopback_pinWiring.png

Initialize and Open the Simulink model

% Open Simulink model
modelName = 'sgMdl_IO131_Loopback';
open_system(modelName);

Model Description

The Simulink model features the IO131 Setup, IO131 Analog Input and IO131 Analog Output blocks Analog Inputs and Outputs 1 and 2 are enabled in the Setup block.

Build, Download, and Run the Example

To run the example, either run the following code section or click the Run on Target button in the REAL-TIME tab in the Simulink model.
% Build the Simulink model
slbuild(modelName); % this will create the real-time application file (.mldatx)
 
% Create and connect to the Speedgoat real-time target machine
tg = slrealtime;
tg.connect;
 
% Download and install the real-time application on the target machine
tg.load(modelName);
 
% Connect the Simulink model with external mode to the real-time application on the target machine
set_param(modelName,'SimulationMode', 'external') % put model into External Mode
set_param(modelName,'SimulationCommand','connect') % connect with External Mode
 
% Start the real-time application
tg.setStopTime(10);
tg.start;
 
% The real-time application on the target machine will automatically stop after 10 seconds

Check the Results

By clicking on the scope after the model has terminated, you should be able to see the input signal of both channels.
If you wish to sample a signal with a sample rate higher than the fundamental sample time of the Simulink model, consider using DMA. Refer to the other examples for the IO131 I/O module on how to configure DMA.

Additional References