Lenze I/O system 1000 System Manual - Manual (Page 257)

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Transmitting process data
Process data transmission mode
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257 EDSIO1000 EN 7.0
Sync telegram for cyclic process data
A special telegram, the Sync telegram, is required for synchronisation when cyclic process
data are transmitted.
The sync telegram must be generated by another node. It initiates the transmission for the
cyclic process data of the I/O system and at the same time triggers data acceptance of cyclic
process data received in the I/O system.
1.
PDO1-TX PDO1-RX
2. 3. 4.
 
epm−t111
Fig. 8−4 Synchronisation of cyclical process data with the help of a sync telegram (asynchronous data not
considered)
 Sync telegram
Transmission sequence
1. After receiving a sync telegram, the I/O system transmits the cyclic process output
data (PDO1−Tx) if "sync−controlled transmission" is active.
2. Once the transmission is completed, the I/O system receives the cyclic process input
data (PDO1−Rx).
3. The data is accepted by the I/O system with the next sync telegram if
"sync−controlled reception" is active.
4. All other telegrams (e.g. for parameter or event−controlled process data) are
accepted asynchronously by the I/O system after transmission.