Cyclic Frames Sync Tasks

A Sync Task is a synchronizing task. It is created when there is a Sync Unit that is assigned to the corresponding synchronizing task.

The MTU (Maximum Transmission Unit) indicates the maximum size (in bytes) of the cyclic Ethernet frames sent from the master device.

The "Sync Tasks" dialog allows you to set the maximum number of Sync Tasks and MTU of cyclic Ethernet transfer frames sent by the master.

WcState

If a subscriber is in the "Init" or "Preop" state, then the "WcState" in the datagram of its associated Sync Unit, to which the subscriber also belongs, has the value 1. Even if there is an internal error in the device, the "WcState" in the datagram of its associated Sync Unit, to which the device also belongs, takes the value 1. If the "WcState" in the datagram of its associated sync unit has the value 1, then the process data of the devices belonging to this Sync Unit are frozen and no longer updated. Nevertheless, acyclic data can be sent from CoE objects or for state queries, for example.

Max Sync Tasks:

In the Sync Tasks dialog, the maximum number of Sync Tasks can be set to 1, 2, 3 or 4 using the "Max Sync Tasks" NumericUpDown control. The default value is 4. At the bottom of the Sync Tasks dialog, all the available Sync Tasks are entered in a table. The number of Sync Tasks cannot exceed the set maximum number.

MTU:

MTU (Maximum Transmission Unit) specifies the maximum size in bytes of the cyclic Ethernet transfer frames sent by the master. The minimum size is 28 bytes: 14 bytes Ethernet header, 2 bytes E88A4 header, 10 bytes EtherCAT header, 0 bytes EtherCAT data and 2 bytes EtherCAT Working Counter. The maximum size is 1514 bytes: 14 bytes Ethernet header, 2 bytes E88A4 header, 10 bytes EtherCAT header, 1486 bytes EtherCAT data and 2 bytes EtherCAT Working Counter.

Frame Repeat Count:

The TwinCAT EtherCAT master supports multiple transfer of EtherCAT frames for increased interference immunity.

	Frame Repeat Count The EtherCAT slave devices used and affected must support the multiple transfer of EtherCAT frames. The slave device manufacturer specifies this in the ESI description.

No Repeat for 1st Task:

If the "No Repeat for 1st Task" checkbox is checked, the frame of the task with the highest priority to which a Sync Unit is assigned is not sent more than once. If "Frame Repeat Count" is greater than zero, this does not affect the task with the highest priority to which a Sync Unit is assigned when "No Repeat for 1st Task" is selected.

No:

Sequential number of the Sync Task in the table.

Name:

Name of the task.

Cycle (µs):

Task cycle time.