PLCGateway

PLCGateway MCP

Connect AI assistants to your plant through PLCGateway.

PLCGateway connects PLCs, CNC machines and controllers (Siemens S7, Modbus, Mitsubishi, Omron, Allen-Bradley, OPC UA and more), and every PLCGateway product has an MCP server built in. This package is a small stdio bridge: MCP clients that start servers as a command (Claude Desktop, Cursor, Cline, Windsurf, …) run it, and it forwards everything to your PLCGateway on your network.

AI client ──stdio──▶ @plcgateway/mcp ──HTTP (your network)──▶ PLCGateway on your premises ──▶ PLCs & machines

• PLCGateway runs on your premises. The bridge talks only to the address you give it; it collects nothing and sends nothing elsewhere.
• The assistant works with the rights of the token you give it, the same roles as people.

What you can ask

• "How many alarms did line 3 have in the last 2 hours?"
• "What was the filler's OEE today, and where did we lose the most time?"
• "Summarise the last 24 hours of the tank level trend."
• "Build a report dashboard with production and energy per shift for line 1." (draft for you to review)
• "Add the Modbus TCP meter at 192.168.1.40 as 'Compressor 2 energy meter'." (needs the MCP configuration token)

Requirements

• PLCGateway SCADA or Connect, reachable from the computer running the AI client, with MCP enabled
• An API token: PLCGateway → Settings → API token (operator rights: read, write, alarm acknowledgement)
• Node.js 18.17 or newer

For setup work (adding devices and tags) create the MCP configuration token in Settings and switch it off when done.

Setup

Claude Desktop, Cursor, Cline and other stdio clients

{  "mcpServers": {    "plcgateway": {      "command": "npx",      "args": ["-y", "@plcgateway/mcp"],      "env": {        "PLCGATEWAY_URL": "http://192.168.1.50:8080",        "PLCGATEWAY_TOKEN": "<your API token>"      }    }  }}

Clients that support HTTP MCP directly

You don't need this package; connect straight to PLCGateway:

{ "mcpServers": { "plcgateway": { "type": "http", "url": "http://192.168.1.50:8080/mcp",                                   "headers": { "Authorization": "Bearer <your API token>" } } } }

On the PLCGateway computer itself

plcgateway-scada --mcp-stdio (or plcgateway-connect --mcp-stdio) can be added as the command directly.

Configuration

For HTTPS with your own certificate authority, set NODE_EXTRA_CA_CERTS=/path/to/ca.pem.

Troubleshooting

The bridge logs to stderr (visible in your client's MCP logs).

Links

• Product: https://plcgateway.com · AI and MCP: https://plcgateway.com/ai-mcp
• Demo: https://plcgateway.com/contact

License

The bridge in this repository is MIT licensed. PLCGateway itself is proprietary software, licensed separately.