LAD Render Cloud — SimaticML ladder diagrams over MCP

LAD Render Cloud — SimaticML → ladder diagram over MCP

LAD Render Cloud renders a TIA Portal SimaticML block (FC / FB / OB) into a PNG ladder diagram — real ladder layout (contacts, coils, timers/counters, branch merges, jumpers, network titles, interface declaration table), not syntax highlighting and not a code screenshot.

Use it so an AI agent's generated ladder logic can actually be looked at, on a machine that has no TIA Portal installed.

This repository is documentation and client configuration only. The service runs at tia.hubwiz.com; its implementation is not open source.

• Endpoint: https://tia.hubwiz.com/render/mcp
• Transport: Streamable HTTP (stateless, POST JSON-RPC)
• Auth: Authorization: Bearer render_live_… (the X-API-Key header is also accepted)
• Dashboard / API keys: https://tia.hubwiz.com/render
• Registry entry: io.github.tia-forge/lad-render-cloud (official MCP Registry)

What it does

initialize / tools/list / render_version are free; every other tools/call costs 1 credit, and one call submits exactly one block.

Inputs and limits

• Accepted: FC / FB / OB blocks in LAD or SCL, including blocks where networks mix both.
• Rejected with an explicit error: GlobalDB / InstanceDB / UDT / tag tables (no ladder diagram to draw) → UNSUPPORTED_DOCUMENT; FBD / GRAPH / STL → UNSUPPORTED_LANGUAGE.
• Options: network renders a single 0-based network; scale (1–3) enlarges the image.
• Limits: input XML 4 MiB, MCP request body 8 MiB, image 32,000,000 pixels with no side over 20,000 px, PNG 12 MiB, rate limit 120 requests/minute. Too tall, or scale too large → render one network instead of the whole block.

How to get SimaticML

In TIA Portal: right-click the block → Export → XML. The saved <Document><SW.Blocks.FC|FB|OB>… text is the SimaticML this service expects. No TIA Portal at hand? Render one of the published example XMLs first.

Quick start

Claude Code

claude mcp add --transport http lad-render https://tia.hubwiz.com/render/mcp \  --header "Authorization: Bearer render_live_YOUR_KEY"claude mcp list

Cursor / VS Code / any JSON-configured client

{  "mcpServers": {    "lad-render": {      "url": "https://tia.hubwiz.com/render/mcp",      "headers": { "Authorization": "Bearer render_live_YOUR_KEY" }    }  }}

First calls

// free — what does this renderer support right now?{ "name": "render_version", "arguments": {} }
// one block → PNG (costs 1 credit){ "name": "render_simaticml", "arguments": { "xml": "<Document>…</Document>" } }
// a single network, 2× larger{ "name": "render_simaticml", "arguments": { "xml": "<Document>…</Document>", "network": 0, "scale": 2 } }

Pricing

No subscription, no monthly fee; balance is applied immediately, and render_version / tools/list never consume credits.

Scope

• Renders text only: it does not connect to TIA Portal, does not read or write a project, and never downloads to a device. For on-premise project work use the TiaLink MCP gateway (https://github.com/tia-forge/tialink) instead.
• Output is for reading and review — it does not replace compiling the block in TIA Portal or commissioning on site.

Related

• TiaLink — TIA Portal MCP gateway, on your machine: https://github.com/tia-forge/tialink
• LadDoc Cloud — LadDoc IR → importable SimaticML: https://github.com/tia-forge/laddoc-cloud
• PLC Cloud Sim — validate and step-run LAD/SCL in the cloud: https://github.com/tia-forge/plc-cloud-sim