Installing the CODESYS Bridge
Set up the PLC Assist bridge inside CODESYS in under a minute.
The CODESYS bridge runs inside CODESYS itself. Once started, PLC Assist can read your project, edit code, build it, and report the errors — all from your browser.
Requirements
| Requirement | Details |
|---|---|
| CODESYS | V3.5 SP21 or later (fully supported); older V3.5 versions work with limitations |
| Operating System | Windows 10 / 11 (64-bit) |
You also need a PLC Assist account.
Setup
1. Download the bridge
In the chat, the bar at the top says No PLC bridge set up yet. Click Set up a bridge — or go to Settings → Bridges — and under Connect a PLC project click Download for CODESYS. You get PLCAssistBridge-CODESYS.zip.
Unzip it somewhere permanent: the codesys-scriptcommands folder holds start_volt_codesys.py alongside the libraries it loads, so the script only works from inside that folder. The download is already tied to your account — there is nothing to copy or paste.
2. Run it in CODESYS
Open your project, then Tools → Scripting → Execute Script File and pick codesys-scriptcommands\start_volt_codesys.py.
The bridge loads inside CODESYS. Leave CODESYS open — closing it closes the bridge.
3. Switch back to the browser
The chat connects through the cloud relay on its own — no port, firewall or localhost configuration. When the bridge is attached, the bar shows CODESYS and the name of your open project.
Stopping the bridge
Run codesys-scriptcommands\stop_volt_codesys.py the same way you started it, or close CODESYS. The bar then shows PLC bridge not connected.
Updating
Only the latest bridge can reach your project. When a newer one is released, the bar shows PLC bridge needs updating with a Download the new bridge link. Download it, replace the old folder, and run start_volt_codesys.py again.
Troubleshooting
The bar says "PLC bridge not connected" but CODESYS is open
Run start_volt_codesys.py again — the bridge stops when CODESYS closes. If it still does not connect, check that the bridge was downloaded while signed in to the same PLC Assist account as the browser: a bridge belongs to the account that downloaded it. Settings → Bridges lists the bridges of your account.
The bar says "Can't reach the connection service"
That is on our side, not yours — your bridge is probably fine. It recovers on its own.
Firewall
The bridge needs outbound WebSocket access to relay.plc-assist.com on port 443. No inbound ports are opened and no port forwarding is needed. If your corporate firewall blocks outbound traffic to that host, allow it.