Ladder Logic Translation using Large Language Models in Industrial Automation

2026-05-29

AI Summary

This study addresses the challenge of migrating ladder logic programs across programmable logic controller (PLC) platforms—such as from Rockwell to Siemens—hampered by vendor-specific syntax and semantics. To overcome this, the authors propose the first automated translation framework that integrates large language models (LLMs) with industrial programming environments. The approach leverages XML parsing, structural normalization, a constrained generative LLM, and integration with the TIA Portal Openness API to achieve, for the first time, a mathematically formalized representation of ladder logic. Structural constraints are imposed during translation to preserve semantic equivalence. Experimental results demonstrate that the pipeline enables high-fidelity, fully automatic cross-vendor translation of ladder logic programs across diverse instruction sets.

Abstract

Ladder logic translation is an important problem in industrial automation because without it, it is difficult to switch Programmable Logic Controller (PLC) vendors. The prevailing translation problem highlights mismatched programming environments, incompatible ladder logic constructs, limitations in terms of differences in the semantic expressiveness of the vendor formalisms and integrated black-box proprietary engineering tools which are exemplified in our example case; Rockwell to Siemens PLC code translation. This work presents a mathematical formulation of the problem, the detailed architecture of a solution which supports XML extraction, structural normalization, constrained generative function (LLM), and system integration via the TIA Portal Openness API as rigorously engineered pipeline for automated translation of Rockwell Ladder Programs to Siemens S7 ladder programs. Finally, we present results that show that the translations retain high semantic consistency across instruction categories.

Problem

• Ladder Logic Translation
• Industrial Automation
• PLC Vendor Switching
• Semantic Expressiveness
• Proprietary Engineering Tools

Innovation

• Ladder Logic Translation
• Large Language Models
• PLC Migration
• Semantic Consistency
• TIA Portal Openness API