When using Simlink real-time (MATLAB 2020a), the following error occurs. Does anyone know the solution?

Hi @子谦,

Thank you for running the slrttest diagnostic and providing the detailed output. This gives us very specific information about what's happening with your Simulink Real-Time setup.

Analysis of Your Test Results

Looking at your test output chronologically:

Tests 1-3: All Successful * Network connectivity (ping tests) - working perfectly * Target PC reboot capability - functioning normally * Basic host-target communication - established and stable

Test 4: Failed at File Operations

The failure occurs specifically during the build and download phase with these key error messages:

• Error opening file from getRunDirectory
• Error writing file during the target load process

This confirms that your network setup and target PC communication are working correctly, but there's a file system issue on the target PC side.

Root Cause Analysis

Based on the error sequence in your diagnostic:

1. The warning about MathWorks.xPCTarget.FrameWork.xPCTargetPC event listener callback

2. The specific getRunDirectory error from HostCommandObjects

3. The final "Error writing file" message

This indicates the target PC cannot create or access its run directory where Simulink Real-Time stores downloaded models and temporary files.

Targeted Solutions (In Order of Likelihood)

1. Target PC Directory Access Issues (Most Likely) The getRunDirectory error suggests the target can't access its default run directory. Try:

% First, check what directory the target is trying to use
tg = slrealtime('TargetPC1');
try
  runDir = tg.getRunDirectory();
  fprintf('Target run directory: %s\n', runDir);
catch ME
  fprintf('Cannot get run directory: %s\n', ME.message);
end

2. Target PC File System Permissions

On your target PC (TargetPC1): * Navigate to C:\ and look for SimulinkRealTime or xPCTarget folders * Right-click → Properties → Security → ensure "Full Control" for current user * If folders don't exist, create: C:\SimulinkRealTime\temp with full permissions

3. Target PC Disk Space Check

Verify available space on target PC's C: drive: * Need at least 1-2 GB free for model compilation and temporary files * Clear any old model files from previous sessions

4. MATLAB 2020a Specific Fix

Since you're using MATLAB 2020a, try this sequence:

% Clear any cached target connections
clear tg
clear all

% Recreate target object with explicit configuration
tg = slrealtime('TargetPC1');
tg.connect();

% Try a simple ping before building
if tg.isConnected()
  fprintf('Connection established\n');
else
  fprintf('Connection failed\n');
end

5. Target Software Refresh

If the above don't work, the target runtime may need refreshing: 1. On target PC, restart the Simulink Real-Time services 2. Or consider reinstalling the Simulink Real-Time target software

Next Steps

Please try solutions 1 and 2 first, as they address the most common causes of the getRunDirectory error.

Can you also run this diagnostic command and share the output?

tg = slrealtime('TargetPC1');
tg.connect();
status = tg.TargetSettings

This will show us the target's current configuration and might reveal additional clues about the directory access issue.

Let me know what you find, and we can drill down further based on the results.

Note: The fact that tests 1-3 passed completely rules out network issues, so we can focus specifically on the file system problem on the target PC.