GUIDE6 min readUpdated Jun 2026

OpenPLC on Raspberry Pi

The open-source IEC 61131-3 runtime that turns a Pi into a programmable controller — free, familiar, and great for learning and non-critical control.

SHORT ANSWER

OpenPLC is a free, open-source runtime that executes IEC 61131-3 programs (ladder, structured text, function blocks) on a Raspberry Pi, with a web editor and Modbus support built in. It's the easiest on-ramp from PLC thinking to a Pi, ideal for education, prototyping and non-safety control — though you'll add a real-time co-processor for tight loops.

IEC 61131-3
languages supported
OpenPLC
$0
open-source, no per-seat license
OpenPLC
Modbus
master/slave built in
OpenPLC

01What it gives you

A web-based editor, the five IEC 61131-3 languages, a runtime that maps to the Pi's I/O (or industrial I/O boards), and built-in Modbus so it talks to existing gear out of the box. It's the closest thing to a free PLC you can flash to a Pi this afternoon.

02Where it stops

OpenPLC isn't certified and isn't deterministic on stock Linux. For non-safety monitoring and control that's fine; for hard real-time or SIL functions, pair it with an MCU or keep those on certified hardware.

Common questions

The ones we're asked on every first call.

For non-safety, non-hard-real-time control, yes — it's used in real deployments. Treat it like any soft PLC: great for supervision and logic, paired with certified gear or an MCU where determinism or safety is required.

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