Slave Configuration: 'Distributed clock' settings
Distributed Clocks (DC) enable EtherCAT network-spanning, exact time synchronization when generating output signals and reading inputs. Timestamps for events are also synchronized in this way. Such a precise time synchronization is especially necessary in motion applications where several axes are moved in a precisely (time) coordinated manner.
To support DC, a slave must implement a synchronizable clock. After PowerOn, the slave first uses its own, internally generated local time. As soon as one slave device is specified to deliver the reference system time, all accordingly configured slaves synchronize their local clocks with the system time. This is always the first slave station connected to the master which supports the DC functionality.
The synchronization of the distributed clock system (and thus in each slave) takes place at the transition from Pre-Op to Op state, i.e. at the start-up of the EtherCAT. Consequently, after changing DC-related parameters, an EtherCAT restart must be performed for the changes to take effect.
Currently, iCube Engineer does not support any user-defined DC-related settings.
To use DC for a slave, proceed as follows:
- Double-click the slave node in the PLANT and open the 'Distributed clock' editor.
- In the drop-down list, specify whether the slave clock should be synchronized.
Using the EtherCAT Online Functions you can get DC-related diagnostic information on each slave.