Troubleshooting

This guide covers common issues and their solutions.

Connection Issues

Browser Blocked the Connection

Symptoms:

• Clicking "Connect" does nothing or fails silently
• You previously clicked "Block" on a browser permission prompt
• Connection worked before but suddenly stopped

Why this happens:

PLC Assist runs in your browser and needs to connect to the bridge program on your computer. Your browser (Chrome/Edge) asks permission for this the first time. If you click Block, the connection is permanently blocked — the browser won't ask again.

How to fix:

1. Copy this and paste it in your browser address bar:

   chrome://settings/content/all

2. Find plc-assist.com in the list and click it
3. Click Reset permissions
4. Close the tab, reload PLC Assist, and click Connect again
5. When the browser asks for permission, click Allow this time

Bridge Won't Connect

Symptoms:

• "Connection failed" error
• Cannot see project in PLC Assist

Solutions:

1. Check your PLC environment is running

   • Ensure your PLC environment (CODESYS, TwinCAT XAE, etc.) is open with your project
   • Verify the project is not in a locked state

2. Check the bridge is running

   • CODESYS: Tools → Scripting → Execute plc-assist-bridge-start.py
   • Beckhoff: Run BeckhoffBridge.exe (should show "Listening on...")

3. Restart the bridge

   • Stop the bridge script/program
   • Wait a few seconds
   • Start it again

4. Check for port conflicts

   • Ensure no other application is using port 8555

5. Check your firewall

   • Ensure localhost connections are allowed on the bridge port

Connection Drops Frequently

Symptoms:

• Connection works but disconnects randomly
• Need to restart bridge often

Solutions:

1. Update the bridge

   • Download the latest scripts from PLC Assist
   • Replace the old files

2. Check system resources

   • Close unnecessary applications
   • Ensure your PLC environment has enough memory

AI Issues

AI Not Responding

Symptoms:

• Chat messages don't get responses
• "Generating..." shows indefinitely
• Timeout errors

Solutions:

1. Check connection status

   • Verify the bridge is connected
   • Refresh the browser page

2. Cancel and retry

   • Cancel the current request
   • Try sending a simpler request

3. Start a new chat

   • Create a new chat session
   • Try your request again

AI Gives Poor Results

Solutions:

1. Be more specific

   • Include data types explicitly
   • Describe behavior in detail
   • See Prompting Tips

2. Provide context

   • Reference existing code in your project
   • Explain your naming conventions

3. Break down the request

   • Make smaller, focused requests
   • Build up incrementally

Compilation Errors

Errors After Accepting Changes

Solutions:

1. Ask the AI to fix them

   • The AI can see the compilation errors and fix them automatically
   • Just ask: "fix the compilation errors"

2. Restart the bridge

   • Stop and restart to force resync

Compilation Not Running

Solutions:

1. Check bridge connection

   • Ensure the bridge shows as connected

2. Check your PLC environment

   • Ensure the project is open and not in a locked state

Still Having Issues?

If none of these solutions work:

1. Collect information

   • Screenshot of the error
   • Steps to reproduce
   • Browser and OS version

2. Contact support

   • Email support at contact@plc-assist.com