Beckhoff EP3356-0022 Documentation page 56

Commissioning/Configuration
Fig. 52: Example correction dialog
It is recommended to check the „Extended Information" box, in order to show differences in the revision.
Color Explanation
green This EtherCAT device matches the entry on the other side. Both type and revision match.
blue This EtherCAT device is present on the other side, but in a different revision.
If the found revision is higher than the configured revision, the slave may be used provided
compatibility issues are taken into account.
If the found revision is lower than the configured revision, it is likely that the slave cannot be
used. The found devices may not support all functions that the master expects based on the
higher revision number.
light blue This EtherCAT device is ignored ("Ignore" button)
red This EtherCAT device is not present on the other side.
Device selection based on revision, compatibility
The ESI description also defines the process image, the communication type between master and
device and the device functions, if applicable. The physical device (firmware, if available) has to
support the communication queries/settings of the master. This is backward compatible, i.e. newer
devices (higher revision) should be supported if the EtherCAT master addresses them as an older
revision. The following compatibility rule of thumb is to be assumed for Beckhoff EtherCAT Termi-
nals/Boxes:
Device revision in the system >= device revision in the configuration
This also enables subsequent replacement of devices without changing the configuration (different
specifications are possible for drives). Example: If an EL2521-0025-1018 is specified in the configu-
ration, an EL2521-0025-1019 or higher (-1020, -1021) can be used in practice.
If current ESI descriptions are available in the TwinCAT system, the last revision offered in the se-
lection dialog matches the Beckhoff state of production. It is recommended to use the last device re-
vision when creating a new configuration, if current Beckhoff devices are used in the real applica-
tion. Older revisions should only be used if older devices from stock are to be used in the applica-
tion.
56 Version: 1.1.0 EP3356-0022