On-Premise AI vs Cloud Copilot
for Siemens TIA Portal
Siemens TIA Portal Copilot sends your PLC code to the cloud. TIA Connect keeps everything local. Compare SaaS AI vs on-premise AI for industrial automation — and why MCP is the future.
The AI Revolution in PLC Programming
Artificial intelligence is transforming how engineers program industrial PLCs. Siemens now offers its TIA Portal Copilot — a cloud-based SaaS assistant integrated into TIA Portal V20+. But for many industrial environments, sending proprietary PLC code and production data to external cloud servers is simply not an option.
TIA Connect takes a fundamentally different approach: a local MCP server (Model Context Protocol) that connects TIA Portal to any AI model — cloud or on-premise — while keeping your data under your control. No vendor lock-in, no mandatory cloud subscription, no data leaving your network.
Siemens Copilot vs TIA Connect: Head-to-Head
Two approaches to AI-assisted PLC programming — one sends your data to the cloud, the other keeps it local
| Feature | Siemens TIA Portal Copilot | TIA Connect (MCP) |
|---|---|---|
| Architecture | Cloud SaaS — code sent to Siemens servers | Local MCP server — data stays on your machine |
| AI Model | Siemens proprietary (no choice) | Any LLM: Claude, GPT-4, Llama 3, Mistral, Qwen... |
| Offline Capability | Requires internet connection | Full offline with local models (Ollama, vLLM) |
| Data Sovereignty | Code processed on external servers | 100% on-premise — nothing leaves your network |
| Cost Model | Per-seat SaaS subscription | One-time license + BYOK (Bring Your Own Key) |
| TIA Portal Versions | V20+ only | V17, V18, V19, V20, V21 |
| IDE Integration | Built into TIA Portal only | VS Code, Cursor, Windsurf, any MCP client |
| Protocol | Proprietary closed API | Open MCP standard (Anthropic) |
Why Data Sovereignty Matters in Industry
In automotive, pharmaceutical, defense, and critical infrastructure sectors, PLC code is classified intellectual property. A production line's control logic represents years of engineering know-how and competitive advantage.
When you use a cloud-based AI copilot, your code — including variable names, process logic, safety routines, and production parameters — is transmitted to external servers for processing. Even with encryption and privacy guarantees, this creates compliance risks under NIS2, IEC 62443, and corporate security policies.
With TIA Connect's on-premise approach, the MCP server runs locally on your engineering workstation. Your PLC project data never leaves your network. You choose whether to route AI requests to a cloud API (with your own key) or to a fully local model running on your hardware.
What is MCP for TIA Portal?
The Model Context Protocol (MCP) is an open standard created by Anthropic that allows AI models to interact with external tools and data sources. TIA Connect implements an MCP server that exposes TIA Portal's Openness API to any compatible AI client.
This means your AI assistant — whether it's Claude in Cursor, GPT in VS Code, or a local Llama model — can directly read your PLC project structure, create and modify blocks, manage tags, compile code, and even download to the PLC. All through a standardized, open protocol.
What the MCP Server Can Do
Running AI 100% Offline with Local Models
For the most sensitive environments — air-gapped networks, defense contractors, classified production lines — TIA Connect supports fully offline AI through local model inference.
Using tools like Ollama or vLLM, you can run open-source models (Llama 3.1, Mistral, Qwen 2.5, DeepSeek) directly on your engineering workstation or a local GPU server. Combined with TIA Connect's MCP server, you get a complete AI-assisted PLC programming workflow with zero internet dependency.
Recommended Hardware
NVIDIA RTX 4090 or A6000 for 70B models. RTX 3090/4070 Ti Super sufficient for 8-14B models that handle most PLC tasks.
Supported Frameworks
Ollama (easiest setup), vLLM (best throughput), llama.cpp (minimal footprint). All expose OpenAI-compatible APIs that TIA Connect can use.
Performance
A 14B parameter model on RTX 4090 generates SCL code at 40+ tokens/second — faster than typing. Response quality rivals cloud models for structured PLC code.
Cost Comparison: SaaS vs BYOK
The Siemens Copilot requires an ongoing SaaS subscription per seat — adding to an already expensive TIA Portal licensing stack. For a team of 5 engineers, this means a recurring annual cost on top of your existing licenses.
TIA Connect uses a one-time license model with BYOK (Bring Your Own Key). You pay once for the software and use your own AI API keys — or run local models at zero marginal cost. For teams using Claude or GPT, typical API costs are 5-15x cheaper than per-seat SaaS subscriptions.
With local models via Ollama, your AI costs drop to zero after the initial hardware investment.
Frequently Asked Questions
Can I use TIA Connect completely offline?
Yes. TIA Connect runs as a local server on your machine. Combined with a local LLM via Ollama or vLLM, you get a fully air-gapped AI assistant for PLC programming. No internet required at any point.
Is TIA Connect's MCP server compatible with Siemens TIA Portal Copilot?
They are independent solutions. TIA Connect uses the open MCP standard and works with any AI model, while Siemens Copilot is a proprietary SaaS feature. You can use both, but TIA Connect gives you more flexibility and data control.
What AI models work best for PLC code generation?
Claude Sonnet/Opus and GPT-4o produce the best SCL code. For local models, Qwen 2.5 Coder 32B and Llama 3.1 70B are excellent. Even smaller 8B models handle routine tasks like tag creation and block documentation.
How does MCP compare to traditional TIA Openness scripting?
MCP builds on top of TIA Openness but adds an AI-native interface. Instead of writing C# scripts, you describe what you want in natural language. The AI uses MCP tools to execute the operations — reading your project context, generating code, and deploying it, all in one conversation.