Omron NX701-17 Series User Manual page 64

3 EtherCAT Communications
Additional Information
Distributed Clock (DC)
This is a unique EtherCAT feature that enables precise clock synchronization. The DC-based
clock synchronization enables sharing the same time between the EtherCAT master and the
slaves. This enables the timing of the operation of the EtherCAT master and slaves to be syn-
chronized with the shared time.
EtherCAT Master
The clock that gives the standard network time is called a "reference clock". The reference clock
is provided either by the master or a slave that supports the function to provide a reference
clock, to the other slaves. As described in the table below, whether the master or slave provides
a reference clock depends on the used CPU Unit.
When NX-series CPU Units Is Used
The EtherCAT master of the NX-series CPU Unit
* Slaves with the DC functionality can provide a reference clock.
The EtherCAT master uses this reference clock to send frames so that the EtherCAT master and
slaves remain synchronized. The slaves that support a distributed clock (i.e., synchronized
slaves) perform advanced time synchronization by performing input and outputs based on the
reference clock.
3-4
Operation timing is synchronized by sharing time
information between the EtherCAT master and slaves.
Slaves with a distributed clock
Of the slaves that provide a reference clock, the
slave that is the closest to the EtherCAT master on
the wiring. In the above figure. the left most slave of
the slaves with the DC functionality.*
NJ/NX-series CPU Unit Built-in EtherCAT Port User's Manual (W505)
When NJ-series CPU Units Is Used