Chapter 2 System Setup
ASDA A2-E
Revision April, 2015
2-11
2.3 Synchronization Modes Setting
2.3.1 Two Synchronization Modes of Delta Servo
ASDA A2-E supports two synchronization modes, Free Run mode and DC-
Synchronous mode. Please note that the asynchronous Free Run mode is still under
the definition of “Synchronization Modes” within EtherCAT specification guide.
Free Run Mode (Asynchronous)
The master and slaves are running in an asynchronous manner. The master and
the slave both have their own clock to calculate the time. In other words, there is no
synchronous clock between the master and the slave. A command sent by the
master and a reply from the slave only consists with a sequential order instead of
strict clock timing. For example, a master sends a PDO at tick t1 and the slave will
receive it at tick t1 or tick t2 and vice versa.
EtherCAT
Data Frame
EtherCAT
Data Frame
EtherCAT
Data Frame
EtherCAT
Communication
Frame
ASDA-A2-E
Application
(Free Run)
Application
Task
Application
Task
Application
Task
Application
Task
No EtherCAT frame
Figure 22 Free Run Mode synchronization
DC-Synchronous Mode (SYNC0 synchronization)
There exists a clock tick for the master and all slaves operation. A data sent by the
master will be received by slave(s) at the same clock interval. The master will inform
all slaves about its clock and ask slaves to align according to the time. A strict clock
tick is always running within this system.
EtherCAT
Data Frame
EtherCAT
Data Frame
EtherCAT
Communication
Frame
ASDA-A2-E Application
(SYN0 Synchronization)
Application
Task
Application
Task
SYN0 Event
SYN0 Event
Figure 23 DC-Synchronous mode synchronization
