5. CONFIGURATION
5.5.12. EtherCAT Master
EtherCAT (Ethernet Control Automation Technology) is a master-slave architecture protocol with high performance, for
deterministic Ethernet, that allows real time performance as it updates 1000 distributed I/O in 30 µS or 100 servomotors axis
each 100 µS using twisted pair cables or optic fiber. Besides, it supports flexible topology, allowing for line, tree and/or star
connections.
An Ethernet frame can be processed in real time instead of being received, interpreted and copied as process data in each
connection. The FMMU (Fieldbus Memory Management Unit) in each Slave node reads the data that are addressed to it at
the same time that the telegram is forwarded to the next device. In a similar way, the input data are inserted as the telegram
is passed. Because of this, the frames are delayed just a few nanoseconds. Access on the Ethernet terminals can be made in
any order as the data sequence is independent of the physical order. It can perform Broadcast, Multicast and between slaves
communications.
The EtherCAT protocol allows a precise synchronization, that is required, for example, in applications where several axis
simultaneously perform coordinated movements, it can be done through an exact adjust of the Distributed Clock. There’s also
the possibility to configure devices that, as opposed to synchronous communication, have an elevated tolerance degree inside
the communication system.
The configuration of EtherCAT modules is initially determined by the Device Description Files of the Master and Slave
devices used, and can be modified by the user in the Configuration Editor dialog boxes. However, for conventional applications
and with the desire of an as easy as possible manipulation, large-scale configurations can be automated by choosing the
Autoconfig mode in Master Parameters.
Note the possibility of modifying the Master and Slave configuration parameters also in operational mode, through the
Master and Slave instances, according to the availability of the device in question.
5.5.12.1. Installing and inserting EtherCAT Devices
In order to be able to insert and configure EtherCAT devices as objects in the device tree, the Slave devices must be
installed.
The Master device is automatically installed by the default MasterTool IEC XE installation. The EtherCAT Master defines
which Slaves can be inserted.
To install the Slave devices the Device Repository must be opened, use the EtherCAT XML Device description Config-
uration File (*.xml) filter and select the device description files (EtherCAT XML Device Description / ESI EtherCAT Slave
Information), supplied with the hardware. The Slave descriptions are available as XML files (file type: *.xml).
An EtherCAT Master can be added to the Devices Tree through the Add Device command, through the context menu of the
CPU NET connectors.
Under a master, one or more slaves can be added, selecting an EtherCAT Master and running the Add Device command
(context menu of the EtherCAT Master) or running the Scan For Devices command.
In addition to the line and tree topologies, MasterTool IEC XE also supports the star topology in EtherCAT. For the
configuration of an EtherCAT star topology, special EtherCAT junctions are needed (in the example: Beckhoff EK1122). A
modular star EtherCAT can be done using various junctions. Individual devices or a complete EtherCAT line section can be
connected in the junction ports. A EtherCAT junction is marked with the icon. The Device Tree example in figure below
shows different possibilities.
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