BECKHOFF EL9800 - Manual (Page 15)

Application Note EL9800 I-13
3.3.3 Distributed Clocks
If t he slave supports DC the master requires a “sync task” to trigger cyclic events. This could be a
simple task (chapter 3.3.4) or a PLC project. The “sync task” shall be set to “Auto start” and linked to
an EtherCAT slave.
If the “sync task” is missing the master remains in PRE-OP State. This setting is enabled by default.
Select [Device xx (EtherCAT)]  tab [EtherCAT] 
[Advanced Settings…]
Figure 11: Master startup behaviour
3.3.4 Append an Additional Task
a. Expand [System – configuration]  right mouse click on [Additional Task]  [Append Task]
Figure 12: Append task
b. Insert an output variable to the task: right mouse click on [Outputs]  [Insert Variable]