CODESYS · IEC 61131-3 · the idea behind it all

Write Once, Run Anywhere

Every other academy here teaches one vendor's tool. CODESYS is the odd one out: it's the programming system embedded inside 1000+ devices from 400+ manufacturers. Your program targets the CODESYS runtime, not the silicon — so the exact same code runs on a WAGO, a Festo, or a Raspberry Pi. Compile it once and download to all three.

📦 one app⚙️ one runtime🏭 many vendors

01 · One program, three machines

The runtime is the trick

Here's your program — a tiny blinker-and-counter POU. Below are three controllers from three different vendors. Each runs the CODESYS runtime on top of its own hardware. Press ⚙️ Compile & download to all and the very same compiled app drops onto every target — then they all run in perfect lockstep, because they're running identical code on an identical runtime.

// PROGRAM PLC_PRG  — your application (one source)
blink_t(IN := NOT blink_t.Q, PT := T#500ms);   // 1 Hz blinker
xLamp := blink_t.Q;
IF blink_t.Q AND NOT qPrev THEN nCount := nCount + 1; END_IF
qPrev := blink_t.Q;

👀 All three lamps blink together and the counters stay in sync — same logic, same runtime, three completely different vendors' hardware. The only thing that differs per target is the I/O mapping (which physical pin xLamp drives). Change targets and your logic never changes; only the mapping does.

Source : codesys.com

02 · Why this matters

The portability dividend

🔁 Skills transfer. Learn CODESYS once and you can program WAGO, Festo, Eaton, ABB, Beckhoff (TwinCAT is CODESYS-derived) and countless OEM controllers. One skillset, a whole industry.

🚪 No lock-in. Outgrew a controller? Re-target the project to a bigger CODESYS device, remap the I/O, download. Your application — the valuable part — comes with you.

🧪 Cheap to learn. The CODESYS runtime even runs on a Raspberry Pi — a full IEC 61131-3 PLC for the price of a snack. Prototype on the Pi, deploy on the industrial target.

🧩 Standards-pure. CODESYS is reference-grade IEC 61131-3 (and pushed OOP into it). Concepts you learn here are the concepts the standard defines — they carry everywhere.

03 · Check yourself

What actually moves?

You finish a project on a WAGO controller, then must redeploy it to an Eaton controller. What has to change?