Zone types

📘 Zone types in the Selmo model

Zones are the smallest but decisive unit in a Selmo model. They connect the logical sequence with the real technology – i.e. with sensors, actuators and internal states.

Each zone describes exactly a signal behavior and is used uniquely in each SEQ.

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🔹 Zones in the context of the Selmo structure

Zones are located below the SEQ and serve as the interface between:

• Process model (Logic Layer)

• Signal control (System Layer – Bit-Control)

• User interface (HMI texts, diagnostics)

• Safety behavior (CMZ, MXIC, Interlock)

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🔄 Overview of zone types

Type	Description	Application
Input	Input signal (sensor, button, safety signal)	Queries, conditions, state changes
Output	Output signal (valve, lamp, actuator)	Control, actions, positioning
In-Out	Combination of output + feedback	Actuator with feedback contact
Mem	Internal state logic (set, reset)	Process marker, intermediate results

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🧠 Typical examples

Type	Example	Explanation
Input	ZI_PartPresent	Sensor detects inserted part
Output	ZC_ClampValve	Output controls clamping cylinder
In-Out	ZIO_SlideOut	Valve with end position sensor
Mem	ZM_PartChecked	Marker “part has been checked” set

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🔐 Extensions per zone

Each zone can additionally be defined as:

• CMZ zone → permanently monitored safety signal

• MXIC zone → button for manual activation, with release condition

• Bear-Check / Pair-Check → plausibility or contradiction check

All these functions are modeled, documented and testable – without additional programming.

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⚙️ Behavior via Bit-Control

In System Layer matrix the behavior of the zone is defined per state:

Symbol	Meaning
0	Zone is inactive
S	Zone is expected to be active (e.g. button, sensor, actuator)
i	Interlock – zone must be correct, otherwise stop

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✅ Summary

Zones are:

• the bridge between model and reality

• clearly typed by signal behavior

• fully documented and exportable

• central elements for safety, diagnostics and control

📌 Every real component of a machine is described uniquely in the Selmo model by a suitable zone – logical, verifiable and traceable.