Lenze DDS v2.3 - Manual (Page 50)

Drive PLC Developer Studio
Programming languages
4-12
l
DDS EN 2.3
4.4.3 Entry and exit action
In addition to the step action, a step may be added an entry action and an exit action.
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An entry action is executed once-only immediately after the step has been activated.
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An exit action is executed once-only before the step is deactivated.
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Entry and exit actions can be implemented in any language.
A step with entry action is identified with an ’E’ in the bottom left-hand corner, the exit action with
an ’X’ in the bottom right-hand corner.
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Double-click the respective corner in the step to edit an entry or exit action.
Example of a step with entry and exit actions:
Note!
Any exit action contained in the active step will be executed during the next cycle only, provided
the subsequent transition is TRUE.
4.4.4 Transition/ transition condition
There are so-called transitions between the steps.
A transition condition must have a value TRUE or FALSE and can therefore consist of
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a Boolean variable
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a de-referenced address to Boolean variable ( poTo_bTest)
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a Boolean constant (TRUE)
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a sequence of instructions with a Boolean result in ST syntax
(e.g. (i<=100) AND b)
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a sequence of instructions programmed in any language
A transition must not contain any programs, function blocks or assignments.
Tip!
The next step can be reached both via transitions and the single step mode.
(SFCtip and SFCtipmode)
4.4.5 Active step
The initial SFC editor call always executes the action pertaining to the initial step.
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A step whose action is being executed is referred to as the active step.
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In online mode, active steps are displayed in blue.
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