EQ Logo - ERQOS

Ladder & IEC 61131-3

Your PLC languages.
Our connected hardware.

The EQSP32 is a supported OpenPLC target. Program it in Ladder Diagram, Structured Text, or Function Blocks with the free, open-source OpenPLC editor and runtime. The languages you have trusted your whole career, running on modern, connected, CE-certified hardware, with no license fees and no vendor lock-in.

Ladder · ST · FBD · IL EQXpansion modules supported Wi-Fi, Ethernet & MQTT intact
EQSP32 controller with IEC 61131-3 ladder logic diagrams
What is OpenPLC

A full IEC 61131-3 environment, open to everyone

OpenPLC is open-source PLC software for industrial automation, education, and research, developed and maintained by Autonomy Logic with a community of thousands of automation professionals. It is free to use, modify, and distribute.

OpenPLC Editor showing a ladder diagram with TON and TOF timer blocks
The OpenPLC Editor: drag-and-drop ladder rungs, variable tables, and the full IEC 61131-3 block library in one IDE.

The Editor

A modern IDE with drag-and-drop visual programming, intelligent autocomplete, and multiple views: ladder rungs, function blocks, or text.

The Runtime

A deterministic, real-time scan engine built for control applications, running the compiled logic on the controller itself.

All four languages

Full IEC 61131-3 support: Ladder Diagram, Structured Text, Function Block Diagram, and Instruction List. The standard, not a dialect of it.

An open community

Thousands of active members, public documentation, and a codebase anyone can inspect. Nothing about your toolchain is a trade secret.

Open vs proprietary

Same languages. Radically different terms.

Nothing changes about how you engineer a machine. What changes is everything around it: what the tools cost, who controls them, and how long they stay available to you.

No license fees, ever

No seat licenses, no dongles, no annual maintenance contract, no per-tag pricing. Every engineer on your team installs the full toolchain on their own machine, today, for nothing.

No vendor lock-in

IEC 61131-3 is a public standard, and the toolchain is open source. Your programs, your engineers' skills, and the software itself cannot be discontinued, paywalled, or held hostage to a support contract.

An open ecosystem

Modbus TCP and open communication are built in, not a paid protocol option. And because the source is public, what the runtime does is auditable, not a black box you have to trust.

The rungs on your screen are the same rungs. The discipline is the same discipline. What you stop paying for is the privilege of using them.

The Erqos integration

IEC 61131-3 on top of a full industrial stack

Our board support package makes the EQSP32 a first-class compile and upload target in the OpenPLC Editor. What makes it different from any other OpenPLC target is what sits underneath: the PLC scan runs on top of the complete EQSP32 library, so everything the controller can do stays available to you.

1

Select the EQSP32 as your device

The board package adds the EQSP32 to the editor's device list. All models are supported. From there it behaves like any other PLC target: write logic, compile, upload over USB.

2

Configure everything in System Layout

One screen holds the whole cabinet. There is no separate pin-mapping table to reconcile: the main unit and every expansion module are configured in the same place, in the physical order they are chained.

3

Bind variables by name, not by address

Every channel gets a readable alias such as XRA.2.RL5 for relay 5 on the second relay module. IEC addresses are assigned automatically underneath, so changing a channel's mode never breaks your program.

4

Keep the connectivity you bought the hardware for

Because I/O runs through the EQSP32 library, the PLC program coexists with the rest of the stack: BLE provisioning through EQConnect, automatic Wi-Fi and Ethernet management, and the library's networking services all keep running alongside the scan.

5

Every EQXpansion module, in your program

Expansion is not an afterthought. Chain up to 15 modules and address every channel from your PLC program, with module-specific settings exposed as configuration instead of code. See the EQXpansion modules →

OpenPLC Editor System Layout with EQSP32 main unit and EQXpansion modules configured
System Layout in the OpenPLC Editor: the EQSP32 main unit, expansion modules, and per-channel mode configuration in one screen. Click to enlarge.

The practical result: a ladder program that can be provisioned from a phone over Bluetooth, updated over the air, and publish to MQTT, without a single rung dedicated to any of it.

EQVersal I/O

Universal I/O, all the way into your rungs

The EQSP32's defining feature is that any channel can be almost any kind of signal. That does not get flattened when you program in ladder: every mode is a dropdown in System Layout, and the channel takes on the matching IEC type automatically.

DIN

Digital input. Standard on/off sensing on any channel.

SWT

Switch input. Hardware debounce, set in milliseconds.

AIN

Analog voltage input. Read directly in millivolts.

CIN

Current loop input. 4-20 mA transmitters, no shunt to size.

TIN

NTC temperature. Linearised on the controller, in tenths of a degree.

PCC

Pulse counter. Flow meters and encoders without a dedicated card.

POUT

Digital or PWM output. On/off, or full duty control at your chosen frequency.

RELAY

Derated relay drive. Full pull-in, then reduced hold power to cut coil heat and current draw.

The same terminal can be a digital input on one machine and a 4-20 mA transmitter input on the next. One part number covers your whole catalogue of designs, and spares are just spares. See how EQVersal I/O works →

Get started

Running in about two minutes

Both halves are free downloads. The board package is a signed kit with an install guide and a fully illustrated user manual covering every mode, module, and setting.

1

Install the OpenPLC Editor

Download the editor (version 4.1.4 or newer) from Autonomy Logic. It is free, and runs on Windows, macOS, and Linux.

2

Download the EQSP32 board package

Get the kit from our GitHub. It contains the signed board-support package, a quick install guide, and the illustrated user manual.

3

Add our signing key, then the package

The editor only accepts cryptographically signed board packages. A one-time script in the kit registers the Erqos public signing key, then you add the package file from within the editor.

4

Select the EQSP32 and build

Choose the EQSP32 as your device, lay out your I/O, and upload over USB. The first compile pulls down the rest of the toolchain automatically.

Coming soon: we are working with Autonomy Logic to have the EQSP32 included as an officially signed vendor in the OpenPLC Editor. When that lands, the signing-key step disappears and the board package installs straight from the editor.

Download the board package Get the OpenPLC Editor
The other two lanes

IEC 61131-3 is one of three ways to program it

The same controller, the same hardware, the same wiring. Move between them whenever a project calls for it.

AI-Assisted C/C++

Describe it in English. Get working C/C++.

When an application needs custom protocols, REST APIs, cloud services, or on-device intelligence, drop into full C/C++ with the library and an AI assistant that writes hardware-aware code.

See AI-assisted coding
Agentic

AI does it ALL. By itself.

An AI agent writes, compiles, and flashes the entire application, then validates its own work on the real EQSP32 through native Hardware-in-the-Loop, unattended.

See how Agentic HIL works

Ladder logic, without the licence desk

Free editor, free runtime, free board package, and hardware that keeps its Wi-Fi, Ethernet, MQTT, and mobile provisioning while it runs your rungs.

Get an EQSP32 Explore EQVersal I/O Compare controllers
Shopping Basket

Contact us for Availability