Automatic mode

6.2 Automatic operation

The Automatic operation is the operating mode in which the system executes the modelled sequence autonomously.

A central principle applies:

In automatic mode the system drives the sequence – not the operator.

Automatic mode is not its own logic, but a system-driven execution of the same model.

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Prerequisites for automatic mode

For a sequence to run in automatic mode, the following conditions must be met:

• the hardware zone is set to Automatic operation switched on

• a valid automatic enablement is present

• no interlock (i) deviation is active

• no CMZ deviation is active

Only when these prerequisites are met may the sequence continue automatically.

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Sequence in automatic mode

In automatic mode the following applies:

• the sequence is in exactly one state

• this state defines expected behaviour (system layer)

• the system continuously evaluates:

  • whether expectations are met

  • whether mandatory conditions are complied with

The sequence proceeds deterministically:

1. A state becomes active

2. S-zones define expected behaviour

3. The system waits for fulfilment

4. The state is considered fulfilled

5. The transition to the next state occurs automatically

The sequence does not react to events, but to the current model state.

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Behaviour in case of deviations

Interlock deviation (i)

If a condition defined as i is violated:

• the automatic release is immediately revoked

• the affected sequence stops

• the current state is retained

• a clear diagnosis is generated

There are:

• no continuation

• no transition

• no interpretation

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CMZ deviation

If a CMZ is violated:

• the reaction takes place hierarchically:

  • sequence level

  • hardware zones level

  • plant level

• all affected sequences are stopped

• no movement is possible anymore

CMZ deviations act:

• state-independent

• independent of operating modes

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Diagnosis in automatic mode

Diagnosis is created in automatic mode automatically from the model.

A diagnosis can be uniquely assigned to:

• a sequence

• a state

• a zone

• an expectation or condition

There are:

• no aggregated messages

• no manually programmed error texts

• no interpretation-dependent messages

The diagnosis explains, why the sequence does not continue.

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Distinction from manual mode

To clarify:

• Automatic operation

  • System drives the process

  • Transitions occur automatically

  • Operator does not intervene in the sequence

• Manual operation

  • Operator influences zones

  • States are deliberately fulfilled

  • Sequence is not continued automatically

Both operating modes:

• use the same model

• are subject to the same supervision

• produce the same diagnostics

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Typical misconceptions about automatic mode

Common misunderstandings are:

• ❌ “Automatic is a faster manual operation”

• ❌ “Automatic skips states”

• ❌ “Automatic briefly ignores deviations”

• ❌ “Automatic is more tolerant than manual mode”

All of these assumptions are false.

Automatic is the strictest operating mode, because it is completely model-driven.

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Summary

Automatic mode:

• executes the modelled sequence autonomously

• reacts deterministically to deviations

• generates automatic, unambiguous diagnosis

• knows no special cases or shortcuts

Automatic means: The model is in control.