Selmo - Documentation of the logic

📘 1. Overview – What is Selmo?

1.1 Introduction

Selmo stands for Sequence Logic Modelling. It is a modern, model-based concept for describing, controlling and documenting machine processes.

Unlike classical PLC programming, Selmo relies on process models (PM):

• visually modeled state logic in the form of deterministic finite automata (DFA) special form as Selmo automaton (SDEA) in sequences (SEQ),

• clear signal assignments via so-called “zones” per SEQ ,

• standardized layer structure (logic, system setup, parameters, display),

• automatic generation of PLC code, HMI for control and monitoring and the process models are produced as documentation.

The goal is: 🧩 to make a machine logically describable, safely controllable and fully documentable – without individual programming logic for the logical process.

🧩Process flow, technology and function are clearly aligned with the requirements and functions are integrated into the logic as standard functions (such as ADD, DIV, PID, soft motion etc.).

🧩The program structure and operating concept are built on the Selmo standard and are applied automatically. Basic requirements, operating modes, shutdown, diagnostics, error messages etc. are automatically included in the program structure.

What the Selmo standard is – and why it is important

Selmo stands for Sequence Logic Modeling – a standard for model-based description and implementation of machine behavior. The Selmo standard defines how machines run logically, which states they go through, how signals are controlled and monitored – and how from that fully traceable control code is created.

At the center is a simple but powerful principle:

Every machine process is modeled as a structured sequence – with clear states, expected conditions and monitored signals.

Through this modeling the behavior of the machine becomes:

• clearly documented,

• deterministically controlled,

• automatically diagnosable,

• and as PLC code fully generatable.

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Why Selmo?

Conventional PLC programs often grow unstructured with the machine. Changes, extensions or troubleshooting therefore become increasingly time-consuming, error-prone and non-transparent.

Selmo solves this problem, by providing a uniform standard for sequence, structure and diagnostics :

✅ Model instead of code: The control code is generated from a graphical sequence model – error-free and traceable ✅ Safety included: States, conditions and interlocks are part of the model – with built-in diagnostics ✅ Structured reusability: Every action (e.g. move cylinder) is defined as a zone – clearly encapsulated and standardized ✅ Intelligent diagnostics: All errors are automatically detected, localized and displayed in the HMI from the model ✅ Manual and automatic operation logically linked – with safe operator guidance through MXIC, CMZ & Co.

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Conclusion

The Selmo standard not only describes how machines should function, but also how this behavior is correctly modeled, secured and implemented is. It is the basis for a new kind of machine automation:

→ structured, safe, traceable – and understandable for everyone involved.