Process data transfer
Cyclic process data objects
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EDSMF2178IB EN 3.0
9.3 Cyclic process data objects
Synchronisation of cyclic process data
The "sync telegram" is used to ensure that the process data can be cyclically read by the
controller and will be accepted by the controller.
The sync telegram is the trigger point for accepting data in the controller and activates the
sending process from the controller. For cyclic process data processing, the sync telegram
must be generated accordingly.
Process data from
Controller
Process data to
Controller
Sync telegram Sync telegram
Cycle time
Fig. 9−2 Sync telegram
After the sync telegram has been received, the controllers send the cyclic process data to
the master. The master reads them as process input data.
When the sending process has been completed, the controllers receive the process output
data (from the master).
All other telegrams (e. g. parameters or event−controlled process data) are acyclically
accepted by the controllers after transmission has been completed.
Acyclic data have not been taken into account for the above figure. When selecting the
cycle time, they must be considered.
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