> For the complete documentation index, see [llms.txt](https://infosys.selmotech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://infosys.selmotech.com/selmo-solution/selmo-solution-en/selmo-documentation/0-entry-and-orientation/what-is-selmo.md). # What is Selmo? Selmo is a **model-based standard** for describing the behavior of machines and systems. The focus is not the code, but: * States * Expectations * monitoring * Reactions From this model arise: * PLC code * HMI structures * diagnosis * Documentation Not separated, not afterwards –\ but **from the same source**. *** ### What Selmo is not To clarify: Selmo is **not**: * a PLC programming standard * a framework with best-practice building blocks * an AI autopilot for machines * a replacement for safety controllers * a UI or HMI concept Selmo does not replace **no responsibility**.\ It makes responsibility **visible**. *** ### Why Selmo exists Modern machines are: * complex * highly automated * legally relevant * safety-critical At the same time, their logic is often: * implicit * distributed in the code * hard to explain * barely verifiable This leads to a fundamental problem: > **Code describes what happens –**\ > **but not why it is allowed to happen.** Selmo exists to answer this “why” formally. *** ### The basic attitude of Selmo Selmo is based on few but strict principles: #### Model before code Code is an implementation.\ The model is the truth. #### Explicit instead of implicit What is relevant is modeled.\ What is not modeled does not exist. #### Determinism At any time it is clear: * which state is active * what is expected * how it reacts #### Behavior instead of signals Signals are physical.\ Behavior is functional. #### Responsibility through traceability What can be explained can be verified.\ What can be verified can be held responsible. *** How this documentation is structured This documentation follows two lines of thought: #### Analytical – from the problem Why classical machine logic reaches its limits\ and what requirements arise from that. #### Synthetic – toward the model How Selmo structures machines: * Plant * Hardware zone * Sequence * Zone * Bit control * CMZ Every content exists **only once**.\ Cross-references replace repetitions. *** One last thought Selmo does not make machines simpler.\ It makes them **clearer**. Clarity is demanding.\ But it is the prerequisite for: * Safety * Scalability * Responsibility * Trust > **Selmo forces clarity –**\ > **so that machines remain explainable.** --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://infosys.selmotech.com/selmo-solution/selmo-solution-en/selmo-documentation/0-entry-and-orientation/what-is-selmo.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.