Write PLC programs on your Mac.
Deploy to ESP32, Linux, or simulation.
The only native macOS PLC IDE with IEC 61131-3 Structured Text, Ladder Diagram, Function Block Diagram, and Sequential Function Chart editors, built-in softPLC runtime, real I/O drivers, and AI-assisted programming. Write once — run in simulation, on a $5 ESP32, or on a production Linux industrial PC.
01 — The Problem
You're running CODESYS in a Windows VM on a $3,000 MacBook.
Industrial automation engineers are increasingly carrying MacBooks into the field. But every PLC IDE — CODESYS, TIA Portal, TwinCAT, Studio 5000 — is Windows-only. You're paying for Parallels, fighting USB passthrough, and watching a 20GB IDE crawl on hardware that should scream.
The Windows VM Tax
Parallels Desktop ($100/yr) + Windows license ($139) + CODESYS runtime licenses. You're paying hundreds before you write a single line of ST. On Apple Silicon, USB passthrough for RS485 adapters breaks unpredictably.
20GB of Bloat
TIA Portal requires 16-20GB just to install. Engineers on Siemens' own forum report 5-10 minute project open times on i7/32GB machines. CODESYS freezes for 15-20 minutes on incremental downloads with large symbol configs.
Multi-Monitor Hell
CODESYS windows appear completely off-screen on multi-monitor Mac setups — unrecoverable without changing display settings. TIA Portal's custom GUI toolkit overdraws onto adjacent monitors. These are bugs engineers have reported for years.
Total Vendor Lock-In
TIA Portal only programs Siemens PLCs. Studio 5000 only programs Allen-Bradley. CODESYS is more open but ties you to Windows. No PLC IDE lets you write vendor-neutral IEC 61131-3 code on the hardware you already own.
02 — Features
A PLC IDE that feels like modern developer tooling.
CodeMirror 6 editor with syntax highlighting. Bytecode compiler. SoftPLC runtime with cyclic scan. Real Modbus I/O. All in ~30MB.
Structured Text Editor
CodeMirror 6 with IEC 61131-3 ST syntax highlighting, bracket matching, code folding, and autocomplete for keywords, types, and standard functions. Feel like you're in VS Code, not a 1990s ladder editor.
Built-in SoftPLC Runtime
Custom bytecode VM with cyclic scan engine. Compile ST → bytecode → run locally. Adjustable scan cycle from 1ms to 1s. Run, Stop, and Step controls. Watch your program execute in real-time — no hardware required.
Modbus TCP + RTU I/O
Real I/O drivers wrapping mt-modbus. Direct address support (%IX0.0, %QW100, %MW200). Map variables to Modbus registers through the I/O mapping panel. Read/write real devices from your ST program.
Live Watch Table
Monitor variable values in real-time while the runtime is running. Add variables to watch, see values update every scan cycle. No more printf debugging — see exactly what your PLC program is doing at every step.
Timer & Counter Blocks
Real implementations of IEC 61131-3 standard function blocks: TON, TOF, TP (timers), CTU, CTD, CTUD (counters), R_TRIG, F_TRIG (edge detection). Not stubs — properly implemented with correct timing behavior.
Diagnostics Panel
Compile errors and warnings with source locations. Inline error squiggles in the editor. See exactly what failed and where — not a cryptic "Compilation failed" dialog.
Dark & Light Themes
Full dark mode and light mode that actually works end-to-end. Modern syntax highlighting in both. Your eyes at 2am on a commissioning call will thank you.
AI-Assisted Programming
Describe logic in natural language, get ST code. Click a diagnostic, get a suggested fix. AI knows your variables, POU structure, and I/O mapping. The first PLC IDE with integrated AI — before Beckhoff ships theirs to Mac.
Multi-File Projects
Project tree sidebar with folder-based .st files. Multi-file tabs with save/load to disk. Go-to-definition for variables and function blocks. Structured like a real software project — because PLC code is software.
Deploy to ESP32-S3
Write ST, compile to bytecode, deploy to a $5 ESP32-S3 microcontroller over WiFi. The VM runs on bare metal with FreeRTOS, connecting to real GPIO, RS485, and Modbus devices. Free runtime — no per-device license.
Deploy to Linux
Run the standalone runtime on RevPi Core, Raspberry Pi, Wago PFC200, UniPi Neuron, or any industrial PC. Full protocol support — Modbus, S7, EtherNet/IP, OPC-UA, MQTT. From $49/device.
Offline Simulation
Built-in softPLC runs on your Mac — no hardware needed. Develop and test your ST programs locally with the watch table and trend chart. Toggle between local simulation and remote deployment with one click.
SCADA Integration
Native connection to Voltrus SCADA for live dashboards, alarm management, and HMI screens. Variables stream directly from the runtime — no OPC-UA bridge required. One ecosystem from code to visualization.
03 — Compare
How it stacks up against the incumbents
Voltrus PLC doesn't try to be CODESYS. It's for engineers who want to write ST code, run it locally, and talk to real devices — on their Mac. Here's the honest comparison.
Honest assessment: Voltrus PLC wins on developer experience, macOS, size, runtime pricing, and ESP32 deployment. CODESYS/TIA/TwinCAT win on protocol breadth and hardware ecosystem (400+ vendors). For ST-based programs on a Mac with real deployment targets — Voltrus PLC is the only native option.
04 — Roadmap
Where we're going: v0.1 → v2.0
Current: v2.0 released with ST + LD + FBD + SFC graphical editors, mixed-language projects, and interactive simulation mode. Deploy to ESP32, Linux, or simulation.
Core Pipeline
ST compiler + bytecode VM + CM6 editor + watch table + runtime controls. Compile → Run → Watch working end-to-end.
Editor & Real I/O
Multi-file projects, project persistence, autocomplete, inline errors, dark/light theme. Modbus TCP driver with I/O mapping. Timer/counter FBs.
AI-Assisted Programming
Claude API + local Ollama integration. AI chat, code generation, code explanation. Context-aware with diff-based apply. Multiple POU types, arrays, templates.
Debugging & Multi-Driver
Breakpoints, single-step, call stack, force variables, trend chart. OPC-UA + Siemens S7 + MQTT + EIP drivers. .voltrus project format, cross-reference.
Production Release
Full IEC 61131-3 ST compliance. Comprehensive standard library. License activation. Auto-update. Direct download via Cloudflare.
Standalone Runtime
Deploy bytecode to ESP32-S3 (free) and Linux industrial PCs ($49-149/device). gRPC for Linux, WebSocket + FlatBuffers for ESP32. SCADA integration. Write once, deploy anywhere.
Graphical Languages
Ladder Diagram (LD), Function Block Diagram (FBD), Sequential Function Chart (SFC) editors with drag-and-drop canvases. Mixed-language projects. Interactive simulation mode with I/O toggle panel.
05 — Runtime
Write once, deploy anywhere
Same ST code runs in simulation on your Mac, on a $5 ESP32 microcontroller, or on a production-grade Linux industrial PC. One compiler, one bytecode format, three deployment targets.
Microcontroller PLC
Turn a $5 ESP32-S3 into a PLC. Flash Voltrus Runtime, deploy your ST program over WiFi, and it runs 24/7 on bare metal with FreeRTOS. Connect to real GPIO, RS485, and Modbus devices.
- 240MHz dual-core, PSRAM
- WiFi + GPIO + RS485
- WebSocket + FlatBuffers transport
- ~140KB RAM available for VM
Industrial PC Runtime
Run on RevPi, Raspberry Pi, UniPi Neuron, Wago PFC200, or any Linux industrial PC. Full protocol support — Modbus, S7, EtherNet/IP, OPC-UA, MQTT. Deploys as a systemd service.
- ARM64 + x86_64
- gRPC remote control + streaming
- Breakpoints, force variables, trend
- mDNS auto-discovery
Built-in SoftPLC
Develop and test without any hardware. The softPLC runs directly in the IDE on your Mac. Watch variables in real-time, set breakpoints, plot trends. Toggle between simulation and remote with one click.
- Zero-config — just press Run
- Adjustable scan cycle 1ms–1s
- Full debugging support
- No hardware dependencies
Write once, deploy anywhere. Same ST code runs in simulation on your Mac, on a $5 ESP32, or on a production-grade Linux industrial PC. No per-device tax on the ESP32 — it's free.
06 — Use Cases
Built for engineers who carry MacBooks into the field.
PLC programming on Mac isn't a niche anymore. Engineering students, field commissioners, machine builders, and IoT developers are all choosing macOS — and they all need PLC tools.
PLC Training & Education
Learn IEC 61131-3 Structured Text without buying a $2,000 PLC trainer. Write code, run it on the softPLC, then deploy to a $5 ESP32 for real hardware experience — all from a MacBook Air.
Field Commissioning
You're on-site with a MacBook. The PLC is running but a register looks wrong. Write a quick ST program, map it to the device's Modbus registers, and verify the behavior — natively, no VM.
Machine Builder R&D
Prototype control logic on your Mac, test in simulation, then deploy to a RevPi or industrial PC running Linux. No CODESYS runtime license per device — $49 for Basic, $149 for Pro with all protocols.
IoT Edge Control
Deploy ST programs to $5 ESP32-S3 microcontrollers for sensor monitoring, or to Linux edge devices for protocol bridging. Free ESP32 runtime — no per-device licensing for your IoT fleet.
Lab & Bench Testing
Test PLC logic without a PLC. Map your ST variables to a Modbus simulator, run scenarios, verify behavior. No hardware on the bench — just your Mac and the app.
Embedded ST Development
If you're building a device that runs IEC 61131-3, use Voltrus PLC as your dev environment. The compiler and VM are Rust crates — integrate them into your own toolchain.
08 — Try It Now
Compile ST code in your browser. No download required.
The same IEC 61131-3 Structured Text compiler that powers Voltrus PLC, compiled to WebAssembly and running right here. Edit the code, hit compile, see the results.
Click Compile to run the
ST compiler in your browser
09 — FAQ
Common questions
v2.0 — Graphical Languages Available
The first Mac-native PLC IDE.
Write once, deploy anywhere.
Four IEC 61131-3 languages (ST + LD + FBD + SFC), softPLC runtime, AI-assisted programming, multi-driver I/O, debugging, mixed-language projects, simulation mode, and deployment to ESP32 and Linux targets.
Compare: CODESYS runtime €50-500/device · TIA Portal PLCSIM €1,500+
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