Ethercat Slave Process Data Settings - Beckhoff EL6751 Documentation

If called, the System Manager searches in the procured device ESI (in this example: EL1202-0000) for
details of compatible devices contained there. The configuration is changed and the ESI-EEPROM is
overwritten at the same time – therefore this process is possible only in the online state (ConfigMode).
5.1.5

EtherCAT slave process data settings

The process data transferred by an EtherCAT slave during each cycle (Process Data Objects, PDOs) are
user data which the application expects to be updated cyclically or which are sent to the slave. To this end
the EtherCAT master (Beckhoff TwinCAT) parameterizes each EtherCAT slave during the start-up phase to
define which process data (size in bits/bytes, source location, transmission type) it wants to transfer to or
from this slave. Incorrect configuration can prevent successful start-up of the slave.
For Beckhoff EtherCAT EL/ES slaves the following applies in general:
• The input/output process data supported by the device are defined by the manufacturer in the ESI/XML
description. The TwinCAT EtherCAT Master uses the ESI description to configure the slave correctly.
• The process data can be modified in the system manager. See the device documentation.
Examples of modifications include: mask out a channel, displaying additional cyclic information, 16-bit
display instead of 8-bit data size, etc.
• In so-called "intelligent" EtherCAT devices the process data information is also stored in the CoE
directory. Any changes in the CoE directory that lead to different PDO settings prevent successful
startup of the slave. It is not advisable to deviate from the designated process data, because the
device firmware (if available) is adapted to these PDO combinations.
If the device documentation allows modification of process data, proceed as follows (see Figure "Configuring
the process data").
• A: select the device to configure
• B: in the "Process Data" tab select Input or Output under SyncManager (C)
• D: the PDOs can be selected or deselected
• H: the new process data are visible as linkable variables in the system manager
The new process data are active once the configuration has been activated and TwinCAT has been
restarted (or the EtherCAT master has been restarted)
• E: if a slave supports this, Input and Output PDO can be modified simultaneously by selecting a so-
called PDO record ("predefined PDO settings").
EL6751
Parameterization and commissioning
Version: 3.5 65