Synchronisation With "Distributed Clocks" (Dc) - Lenze C750 Commissioning

Configuring the network
EtherCAT
Advanced configuration
8.1.10.2

Synchronisation with "distributed clocks" (DC)

Engineering PC
Fig. 2: EtherCAT bus system with c750 controller and i700 servo inverter
The DC synchronization is set using the »PLC Designer«.
The Distributed Clocks (DC) functionality enables an exact time leveling for applications, in
which several axes execute simultaneous, coordinated movements. The data is accepted
synchronously with the PLC program. For DC synchronization, all slaves are synchronized with
a reference clock, the so-called "DC master".
Synchronous communication
The DC synchronization provides for a phase-synchronous operation of master and slaves:
Within one bus cycle, the setpoints are accepted and the actual values are detected in the
field devices at always exactly the same time. If the Lenze controller (master) is synchronous
with the distributed clocks, the actual values acquired by the slave are sent to the master at
the end of the bus cycle and setpoints from the master are sent to the slaves for processing.
When the next DC synchronization event occurs, the data is accepted.
The DC synchronization is only carried out in the Operational state.
After an Out-of-sync occurrence, the EtherCAT master synchronizes the slaves.
Successful synchronization is indicated by means of the In-Sync message.
Test of DC synchronicity
DC synchronicity is only available in the Operational state.
DC synchronicity check in the »PLC Designer«
EtherCAT master: In the Diagnostic master tab, DC In-Sync is set to TRUE if the DC master
•
and all DC slaves have been synchronized.
L_ETC_GetMasterDiagnostic function block (FB)/visualization of the
•
L_ETC_GetMasterDiagnostic function block
DC In-Sync is set to TRUE at the oDiagnostic.xDC_InSync output if the DC master and all
DC slaves are synchronized.
L_IODrvEtherCAT function block (FB) DC In-Sync is set to TRUE at the
•
xDistributedClockInSync output if all DC slaves are synchronized.
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Ethernet
EtherCAT