> 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-templates-and-tools/selmo-operation-and-control-concept-md.md). # Selmo operation and control concept (md) ## Selmo operating and control concept ### Structure, function and safety *(Basis for operating instructions according to ISO/IEC 82079-1)* *** ### 1. Purpose of the document This chapter describes the machine's operating and control concept, whose control system is based on the **Selmo method (Sequence Logic Modelling)** It serves to explain the logical mode of operation, the safety mechanisms and the interaction between operator, machine and control. *** ### 2. Target audience This documentation is intended for: * Machine operators and plant operators * Maintenance personnel and service technicians * Inspectors, auditors and CE officers * Integrators and software engineers who work with Selmo Studio *** ### 3. Overview of the system principle The machine control follows the principle of **deterministic sequence control (Selmo SEQ)**. **Key features:** * The control works with **states** instead of individual commands. * At any time **only one state is active**. * Transition to the next state occurs **only when all defined conditions are met**. This structure ensures reproducible, traceable and safe behavior of the machine. *** ### 4. Control architecture #### 4.1 Structure of the layers The control is hierarchically structured into: 1. **Plant (entire system)** – describes the logical overall structure of the machine. 2. **Hardware zones (HWZ)** – physical areas with their own control logic (e.g. stations, modules). 3. **Sequences (SEQ)** – sequence controls within an HWZ. 4. **Zones (Zone Types)** – logical function blocks that map real signals or virtual functions. *** #### 4.2 The switching engine (Sequence Engine) The switching engine is the sequence and clock generator.\ It continuously checks three core conditions: | Input quantity | Meaning | | ------------------------------- | ----------------------------- | | **AR (Auto Release)** | Automatic release active | | **¬I (No Interlock)** | no safety violation | | **ΣS (Sum of Sequence Checks)** | all ongoing actions completed | Only when **AR = 1 ∧ ¬I ∧ ΣS = 0**, the state change occurs.\ This ensures that the sequence is only continued in a safe state. *** ### 5. Zone level and behavior #### 5.1 Definition Zones are standardized switching elements that bundle actions and feedback.\ They establish the connection between logic and physics. *** #### 5.2 Zone types | Type | Description | Example | | ----------- | ----------------- | --------------------------- | | **IN** | Input signal | Start button, sensor | | **OUT** | Output signal | Lamp, valve | | **IN\_OUT** | Action + feedback | Cylinder, axis, calculation | | **MEM** | Memory zone | Software status, parameter | *** #### 5.3 Operants (Bit-Control) Each zone has an assigned function in each state. | Operant | Meaning | Effect | | ---------------------- | --------------------- | ------------------------------- | | **S (Sequence Check)** | Action active | waiting for feedback | | **I (Interlock)** | Safety monitoring | stops sequence in case of error | | **M (Monitoring)** | Diagnostic monitoring | reports notice without stop | | **0 (Don’t Care)** | inactive | no function in this state | This assignment is defined in the **System Layer** in Selmo Studio. *** ### 6. Safety functions The system contains several standardized safety mechanisms: 1. **Interlock function** – detects safety violations and stops the sequence. 2. **PairCheck** – monitors contradictory feedback (e.g. cylinder front/back). 3. **MXIC (Manual Cross Interlock)** – prevents unsafe hand movements. 4. **Monitoring (M)** – provides diagnostic messages without interrupting the process. All safety functions are an integral part of the Selmo standard – no additional programming required. *** ### 7. Operation via the HMI The user interface shows: * the active state * active zones with color coding * plain text HMI messages * error and diagnostic lists **Color coding:** | Color | Meaning | | --------- | ------------------ | | 🟩 Green | AutoRelease active | | 🟥 Red | Interlock | | 🟨 Yellow | Warning | | ⚪ Grey | Manual Mode | The HMI also serves as an operating interface, diagnostic tool and documentation view. *** ### 8. Behavior in case of malfunctions If a zone reports a deviation: 1. The sequence is automatically stopped. 2. The affected zone is marked in red. 3. An error message with cause appears on the HMI. 4. After error correction and release (AR = 1) the control resumes the sequence. This ensures that no uncontrolled movements occur and that every error can be localized. *** ### 9. Documentation and traceability The Selmo structure documents itself: * Every state, every zone and every operant are stored in the model. * HMI texts and diagnostics are generated automatically. * Changes are versionable and auditable. In this way, the control meets the requirements for traceability, CE conformity and quality assurance. *** ### 10. Summary The Selmo structure defines a clearly traceable and safe control system: * formal state description (deterministic) * standardized zone logic * integrated safety functions * automatic diagnostics and documentation **Advantages:** * Transparent processes * Unambiguous error messages * Safe operation * Uniform structure for all systems *** ### 11. Reference This concept is based on the Selmo standard according to the development guidelines of\ **Selmo Technology GmbH – Sequence Logic Modelling System (SEL\_SEQ\_STD-DE-V3.0)** *** > **Note for documentation editors:**\ > This text is the static section of the operating manual.\ > Dynamic parts (state descriptions, HMI lists, sequence flows) are automatically supplemented from the model. --- # 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. 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