Commissioning
EL3692
87
Version: 2.1
Fig. 119: “Process Data” tab
The process data (PDOs) transferred by an EtherCAT slave during each cycle 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, EM, EJ and EP 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”).
