Simply explained - SDEA

🎓 The Selmo automaton simply explained – control, monitoring and memory

🧩 What is an automaton?

One Automaton is a model that describes, how a machine thinks and reacts in states:

• It is always in a State

• It switches to the next state, when certain conditions are met

• In each state something happens: A motor runs, a cylinder moves, a light turns on

This is how every machine control works – only usually invisible. Selmo makes the visible, understandable and formally describable.

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🧠 How does the Selmo automaton work?

1. States

Imagine your machine thinks in clear steps:

• "Insert part"

• "Clamp cylinder"

• "Processing running"

• "Release"

• "Remove part"

Each of these steps is a state in the Selmo automaton.

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2. zones

A Zone is a building block in the control – it describes e.g.:

• risk rating Push button

• a valve

• risk rating Sensor

• or a pure memory bit

Zones are linked to states – via a table, that precisely says:

• What should the zone do in the state?

• Should it switch something?

• Should it monitor something?

• Or is it irrelevant right now?

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3. The Bit Control Matrix

This table connects zones with states and says for each combination:

Symbol	Meaning
0	Zone is in state irrelevant
S	Something is expected (e.g. that a sensor switches)
I	Zone is monitored – on deviation Error!
M	Zone is monitored - on deviation documented

These four letters control and monitor the entire sequence.

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4. What happens when a state is active?

• Zones with S → perform something or wait for something Example: Cylinder moves → sensor should report: "I have arrived"

• Zones with I → are strictly monitored, on deviation automatic stops Example: A cylinder must be in position – if not: Stop!

• Zone with M → are strictly monitored, on deviation automatic stays on, but documented

As long as not everything is fulfilled, the state waits → the HMI indicates, what is still missing.

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5. How does the machine remember something?

With the Mem zones:

• A Mem zone is a memory: something happened

• Example: "Part was inserted" → is remembered

• Later one can react to it: "If part is present, then..."

The machine remembers logically – not by programming tricks, but clearly modeled.

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6. What is special about Selmo?

Selmo turns a machine into a thinking, comprehensible sequence automaton:

Characteristic	Explanation
State-based	Each state is defined – there is no "hidden logic"
Visually modeled	You can see the sequence and every expectation
Monitoring built-in	Errors are detected automatically
Memory function	Machine remembers what has happened
Operator guidance in the HMI	Shows exactly, what is currently expected
Safety integrated	States stop automatically on deviation
No code required	Everything is created from the Model

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📦 What does this bring in practice?

• Fewer errors during commissioning

• Shorter development time

• Safe processes in automatic and manual operation

• Clear diagnosis in case of malfunctions

• Automatic documentation of control behavior

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🎯 Summary – The Selmo automaton is:

• One thinking sequence

• The Blueprint for the machine's behavior

• A combination of:

  • control (what happens)

  • Monitoring (what is checked)

  • Memory (what is remembered)

And the best part: Everything is unambiguous, verifiable, documentable – all without programming tricks.