Lenze E84DGFCT - Manual (Page 32)

Communication manual 8400 motec EtherCAT®
Data transfer
32
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EDS84DMOTECAT EN 2.1 - 11/2012
7 Data transfer
EtherCAT transmits data in so-called "EtherCAT frames". The EtherCAT nodes only extract
the data intended for them while the EtherCAT frame passes through the device. At the
same time output data are inserted into the frame while it passes through the device. Read
and write accesses are only executed on a small section of the entire EtherCAT frames – the
datagrams. Therefore it is not necessary to receive the complete frame before it can be
processed. The processing starts as soon as possible.
EtherCAT transmits process data, parameter data, configuration data, and diagnostic data
between the host (master) and the controllers (slaves) that are part of the fieldbus. The
data are transmitted via corresponding communication channels depending on their time-
critical behaviour (see Process data transfer
( 37)
/ Parameter data transfer
( 43)
).