As a high-level language software engineer, I cannot write PLC ladder logic. Beyond the architectural differences, I simply had no desire to learn vendor-locked code that can only be used in highly restricted environments.
So, I decided to take a different approach: "Why not build a modern software controller where control logic can be written entirely in high-level languages?" This led me to develop OCA (Object-oriented Control Architecture).
It all started with an attempt to import existing PLC code into OCA by adding a feature to convert Structured Text (ST) into C++. The robust conversion mechanism I implemented turned out to be capable of not only converting ST to C++, but also translating ST code between different PLC vendors.
This software is the standalone ST conversion engine, extracted directly from the OCA framework.
This tool converts Structured Text (ST) code used by various PLC vendors into ST code for other vendors, or into high-level programming languages. Unlike simple regex-based string replacements, this conversion is powered by a robust and advanced parsing architecture.
To use this tool, you need the following software installed on your system:
- Python
- Microsoft Visual C++ Redistributable
- Run the included
start_server.batfile. This will launch a simple Python web server in the background. - Open
index.htmlin your preferred web browser.
- Close the ST Code Converter page in your web browser.
- Close the Command Prompt window running the Python web server.
- Scope of Conversion: The converter processes ST code at the function level.
- Note: Code that defines data types in ST (a format adopted by certain vendors) is not supported and will not be converted.
- System Calls: Vendor-specific system calls are retained using their original function names. A comment will be automatically appended to these lines, indicating that the specific feature requires manual re-implementation in the target environment.
- Processing Limit: You can convert exactly one function per execution.
- Conversion Limitations based on Language Specs: Conversions from vendors with rich ST language specifications (e.g., Siemens, Rockwell, Omron) to vendors with more limited specifications (e.g., Mitsubishi, IEC Standard) may not always succeed due to missing equivalent language features.
- Beta Testing Limitations: Currently, it is difficult to obtain testable ST code in the wild, which means our actual conversion testing is limited. Please expect bugs and unexpected behaviors.
- Not a Silver Bullet: This tool does not guarantee a 100% perfect, ready-to-run conversion to the target vendor's code. Manual adjustments will likely be required.
- Clean Room Implementation: The parsing and conversion logic is implemented strictly based on publicly available ST specifications provided by the respective vendors. No confidential, proprietary, or trade secret information is included in this tool.
We need your help to improve the converter's accuracy!
- Report Bugs: If you discover a problem, please open an Issue. We will review and address them sequentially to improve the tool.
- Share Failed Conversions: If you encounter ST code that did not convert correctly, please share the snippet in an Issue so we can analyze and enhance the underlying engine.
👉 Support ST Code Converter on FundRazr
We have launched a crowdfunding campaign to secure funding for the continuous development and quality improvement of the ST Code Converter. As an independent, developer-driven project, your support is crucial. Donations will go directly toward expanding PLC vendor compatibility, refining the core AST parsing engine, and keeping this project alive and evolving.
If you find this tool valuable or share our vision of modernizing industrial control software, 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！
👉 Support ST Code Converter on FundRazr
ST Code Converter の品質向上（構文解析エンジンの精度強化や対応PLCベンダーの拡充など）および開発継続のために、皆様からのご支援を募集しております。 本ツールが業務の役に立ったという方や、私たちの「産業用制御ソフトウェアのモダナイズ」というビジョンに応援・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.
This source code and related documentation are the proprietary property of Satoshi Murakami. Unauthorized copying, distribution, modification, or use of this file, via any medium, is strictly prohibited.
- Asset Acquisition: For inquiries regarding technology transfer or IP acquisition, please contact the author directly.
Strictly Confidential.