Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 400)

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The Resources
398 DMS 3.2 EN 02/2011 TD29

Transmit on change: Variables are written only when their values change; an
entry after Minimum can, however, set a minimum time lapse between transfers.
Transmit on event: The variables of the list will be written as soon as the variable
inserted at Variable gets TRUE.
Global Network variables lists are marked by the symbol in the Object Organizer.
Note!
If a network global variable is used on one or more tasks, the following applies to
the time component of the transfer: When each task is called it is tested to
determine which parameters apply to the transfer of the variable value
(configuration in the 'Global variables list' dialog). The variable value will be
transferred or not, depending on whether the specified time interval has passed. At
each transfer the time interval counter for this variable is reset to zero.
Sending is always undertaken from the run-time system of the controller affected.
Thus no control-specific functions have to be provided for the data exchange.
Editing Global Variable and Network Variable Lists
The editor for global variables works similar to the declaration editor. But note that
you cannot edit in this editor an list, which is an image of an linked external variable
list ! External variable lists only can be edited externally and they will be read at each
opening and compiling of the project.
Syntax:
VAR_GLOBAL
(* Variables declarations *)
END_VAR
Network variables only can be used, if allowed by the target system. They are also
defined in this syntax.