📘 Requirements for the realization of a machine with Selmo

🎯 Objective

Secure, verifiable, CE-compliant realization of a machine based on the Selmo standard. → Clear specifications for mechanics, electrical, control and documentation.

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🔧 1. Technological prerequisites

Sensing:

• Every relevant position must be uniquely identifiable by a sensor.

• Safety-relevant sensors must be implemented redundantly / reliably.

Actuation:

• Actuators must be switchable and, if necessary, provide feedback.

• Every movement must be safeguarded via i or CMZ.

Safety interfaces:

• Emergency stop, door contacts, air pressure etc. must be representable as CMZ.

• Safety behavior must be able to be modeled deterministically.

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🧱 2. Structural requirement (Selmo principle)

markdownCopyEditPLANT
└── HWZ
    └── SEQ
        └── ZONE

• Every logical subprocess must be represented in a SEQ.

• Each zone must unambiguously have: type, IO, signal, function.

• Each zone must be defined per state (0, S, i).

• Zones may not be used multiple times – no overlap.

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🔁 3. Sequence logic

• Every sequence must be modelable as a state machine model.

• No behavior may be “hidden” in code or side effects.

• All interlocks, CMZ, MXIC must be visible in the model be.

• Reset behavior and restart must be clearly described and testable.

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💻 4. Requirements for PLC + engineering

• Control system must support IEC-61131-3 (ideally Structured Text).

• Code is fully generated from the model – no side coding.

• Project structure with GVL, POUs, Zones, SEQs is mandatory.

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📋 5. Documentation & traceability

• Complete IO mapping (Zone ↔ IO ↔ Address ↔ Terminal)

• CMZ and MXIC matrices with description and reaction

• Parameter structure: IN/OUT, function, interface

• Change log (Model_ChangeLog.csv)

• Validation evidence (e.g. HMI test, sequence check)

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✅ Project approval – checklist

Criterion	Must be fulfilled
Structure complete	PLANT → HWZ → SEQ → Zone
Logic modeled	State-driven sequence (DEA)
Safety represented	CMZ, MXIC, interlock in the model
IO clearly assigned	Signal = Zone = Address = Terminal
Documentation generated	Model → Export → PDF/CSV
Validation performed	Test run + fault check
Restart described	Reset logic + HMI guidance available

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📌 These requirements are binding for every Selmo project. They create the basis for:

• safe machines,

• clear interfaces between trades,

• automated documentation,

• and legally secure CE conformity.