3 Basics | IL•1F CANopen DS301 |
3.5Synchronization
The synchronization object SYNC controls the synchronous exchange of messages between network devices for purposes such as the simul- taneous start of multiple drives.
The data exchange conforms to the
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SYNC- Producer |
Figure 3.25 SYNC message
Time values for synchronization Two time values define the behavior of synchronous data transmission:
•The cycle time specifies the time intervals between 2 SYNC mes- sages. It is set with the object Communication cycle period(1006h).
•The synchronous time window specifies the time span during which the synchronous PDO messages must be received and trnasmitted. The time window is defined with the object Synchronous window length (1007h).
| SYNC | |
T_PDO (status) | ||
R_PDO (controller) | ||
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SYNC |
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synchronous | process | |
time window | R_PDO data | |
cycle time |
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Figure 3.26 Synchronization times
Synchronous data transmission From the perspective of a SYNC recipient, in one time window the status data is transmitted first in a T_PDO, then new control data is received via an R_PDO. However, the control data is only processed when the next SYNC message is received. The SYNC object itself does not transmit data.
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44 | Fieldbus interface |