> 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/2-selmo-big-picture/the-selmo-overall-model.md). # The Selmo overall model ### The fundamental structural principle Selmo describes a machine **not as code**,\ but as **a hierarchically constructed behavior model**. The structure is clearly layered: Plant\ └─ Hardware Zone\ └─ Sequence\ └─ Zone These levels are: * clearly separated from each other * each uniquely responsible * intentionally kept simple *** ### Plant The **Plant** represents the **entire machine or plant**. It is: * the top structural level * holder of global states * place for plant-wide monitoring (e.g. CMZ) The Plant describes **no sequence**.\ It forms the **framework**in which all other elements exist. *** ### hardware zone A **hardware zone** encapsulates a **real plant section**. It is responsible for: * modes of operation (Manual / Automatic) * automatic enablement * start and stop logic * higher-level responses to errors The hardware zone: * contains multiple sequences * knows **no** process logic * does not decide *what* happens, but *whether* is allowed to happen *** ### Sequence A **Sequence** is a **functional process responsibility**. It describes: * a self-contained process * as a deterministic state machine * with clearly defined start and end behavior Typical examples: * Clamp * Machine * Inspect * Release > **One task → one sequence.** *** ### Zone A **Zone** provides the **Connection to real technology** . It: * encapsulates signals * gives them meaning * is uniquely diagnosable Zones are: * always part of a sequence * carriers of monitoring and safety * the smallest meaning-bearing unit in the model *** ### Layer Each sequence is layered across multiple **Layer** . These layers deliberately separate different aspects: #### Logic layer * describes the process * states and transitions * no technology #### system layer * links states with zones * defines expected behavior * implements bit-control #### Parameter layer * contains times, positions, repetitions * no logic, no states > **Layers separate thinking from implementation**\ > **and prevent mixing of responsibilities.** *** ### Interaction of the elements All elements together form a complete picture: * The **Plant** defines the overall framework * The **hardware zone** regulates operation and authorization * The **Sequence** describes the process * The **Zone** ties down technology * The **Layer** structure the description Thus machine behavior is: * explicitly described * assessable at any time * fully traceable *** ### Classification This chapter is intentionally **overview-like**. The following chapters: * delve into each level individually * explain behavior, monitoring and operation in detail > **The overall model is the map.**\ > **The next chapters explain the individual places.** --- # 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/2-selmo-big-picture/the-selmo-overall-model.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.