OCA is a modern Software controller (not SoftPLC) / industrial automation runtime written in C++20. It provides deterministic real-time control on Linux/Windows and ARM devices. Targets include Siemens IOT2050, Raspberry Pi, and general-purpose x64 hardware.
OCA challenges the 40-year stagnation of industrial control.
For decades, the industry has been held hostage by proprietary hardware and outdated programming paradigms (IEC 61131-3). We believe that General Purpose OS (Windows/Linux) + Modern C++ can outperform dedicated hardware PLCs when architected correctly.
OCA is not just a "SoftPLC". It is a deterministic control kernel built from scratch with C++20, designed to prove that software engineering can reclaim the factory floor.
The following performance has been verified on commercial off-the-shelf (COTS) hardware:
| Metric | Performance | Hardware | OS |
|---|---|---|---|
| Cycle Time | 3.6 µs (stable) | Siemens SIMATIC IOT2050 | TI AM65x (RT Linux) |
| Cycle Time | 10.0 µs (stable) | Raspberry Pi Zero 2 W | Yocto Linux |
| Jitter | < 1.0 µs | - | - |
| Runtime Allocation | 0 bytes | All Platforms | No GC, No new/malloc |
"99% of 'PC-based control' projects fail due to Garbage Collection pauses. OCA solves this by enforcing a strict Zero-Allocation architecture during the runtime cycle."
Breaking away from the "Copy & Paste" culture of Function Blocks (FB).
- Inheritance & Polymorphism: Create a base class
Conveyorand deriveConveyorWithSensor. Modify the base, and all 100 instances update instantly. - Vendor Compatibility: Includes wrapper libraries for Siemens (P_TRIG, TON) and Mitsubishi (PLS, SET) to bridge the gap for traditional OT engineers.
- VS Code Integration: Full-featured extension for Windows.
- Cross-Compilation: Docker-based build pipeline hidden behind a single "Build" button.
- One-Click Deploy: Automated SCP transfer, permission setting, and service restart via SSH.
Development Environment:
- Windows 10/11 (Visual Studio Code)
Runtime Targets:
- x64 Windows: For development and simulation.
- x64 Linux: Ubuntu / Debian / RedHat.
- ARM64 / ARMv7: Siemens IOT2050, Raspberry Pi 3/4/5/Zero2W (via Yocto/Debian).
Test Condition: In this test, OCA commands an external PLC over a general-purpose network (TCP/IP) to toggle an output ON and OFF at a strict 1-second (1000ms) interval. The target PLC logs the actual timing of these state changes, and the resulting data is summarized below.
Technical Evaluation: While the OCA kernel itself operates stably at a cycle time of under 10µs, the observed jitter (approx. ±50ms) is a physical constraint entirely originating from standard TCP/IP communication delays and the target PLC's own scan time fluctuations.
Against the 1000ms expected interval, the average interval achieved was 999.347ms (an astonishing average error of less than 1ms). There are absolutely no unpredictable delays, system freezes, or panic pauses caused by garbage collection or OS interrupts. This data clearly proves that OCA's architecture fundamentally eliminates sources of unpredictable latency, ensuring it operates in a strictly deterministic manner on a general-purpose OS.
The actual control processing is executed within OnExecute().
The implementation classes of user logic are instantiated at startup, and their OnExecute() methods are called repeatedly. Unlike typical event-driven programming, understand that control logic is characterized by being called repeatedly at high frequency.
Use buffer areas created in the constructor via member variables within OnExecute(), or use tags configured as Internal tags to reduce memory allocation overhead. When securing buffers with Internal tag settings, you can use BYTE array declarations (e.g., BYTE[10]; other types like Word cannot be used in array declarations).
One scan consists of all OnExecute() methods implemented in user logic being called. Even for controls where real-time performance is not critical (such as conveyors), typical hardware controllers have scan cycle times in the range of several milliseconds. Systems with several thousand steps of ladder logic may consider it a control error if the total exceeds 150ms. Always strive to minimize processing time in your OnExecute() implementation.
We have launched a crowdfunding campaign to secure funding for the continuous development and enhancement of OCA (Object-Component Automation). As an independent, developer-driven project, your support is crucial. Donations will go directly toward refining our deterministic C++20 control kernel, expanding hardware/OS target optimizations (like Siemens IOT2050 and Raspberry Pi), and keeping this project alive to shatter the outdated paradigms of industrial automation.
If you share our vision of democratizing industrial control and moving beyond the limitations of traditional hardware PLCs, please consider backing us. Every contribution makes a huge difference. Thank you for your support!
開発資金調達のためクラウドファンディングを開始しました！
次世代C++ソフトウェアコントローラー『OCA』の開発継続および品質向上（汎用OS上での決定論的制御カーネルの強化、産業用エッジデバイスへの対応拡充など）のために、皆様からのご支援を募集しております。
既存のPLC業界にはびこるベンダーロックインや「なんちゃってオブジェクト指向」の限界を打破し、「産業用制御の民主化」という私たちのビジョンに応援・賛同いただける方からのご寄付を心よりお待ちしております。ご協力いただけると大変助かります！！
Copyright (c) 2016-2026 Satoshi Murakami. All Rights Reserved.
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