General Notes - Ethercat Slave Application - Beckhoff EL922 Series Documentation

PDO list
List of all PDOs supported by this EtherCAT device. The content of the selected PDOs is displayed in the
PDO Content list. The PDO configuration can be modified by double-clicking on an entry.
Column Description
Index PDO index.
Size Size of the PDO in bytes.
Name Name of the PDO.
If this PDO is assigned to a Sync Manager, it appears as a variable of the slave with this
parameter as the name.
Flags F
M
SM Sync Manager to which this PDO is assigned. If this entry is empty, this PDO does not take
part in the process data traffic.
SU Sync unit to which this PDO is assigned.
PDO Content
Indicates the content of the PDO. If flag F (fixed content) of the PDO is not set the content can be modified.
Download
If the device is intelligent and has a mailbox, the configuration of the PDO and the PDO assignments can be
downloaded to the device. This is an optional feature that is not supported by all EtherCAT slaves.
PDO Assignment
If this check box is selected, the PDO assignment that is configured in the PDO Assignment list is
downloaded to the device on startup. The required commands to be sent to the device can be viewed in the
Startup [} 91] tab.
PDO Configuration
If this check box is selected, the configuration of the respective PDOs (as shown in the PDO list and the
PDO Content display) is downloaded to the EtherCAT slave.
7.4

General Notes - EtherCAT Slave Application

This summary briefly deals with a number of aspects of EtherCAT Slave operation under TwinCAT. More
detailed information on this may be found in the corresponding sections of, for instance, the EtherCAT
System Documentation.
Diagnosis in real time: WorkingCounter, EtherCAT State and Status
Generally speaking an EtherCAT Slave provides a variety of diagnostic information that can be used by the
controlling task.
This diagnostic information relates to differing levels of communication. It therefore has a variety of sources,
and is also updated at various times.
Any application that relies on I/O data from a fieldbus being correct and up to date must make diagnostic
access to the corresponding underlying layers. EtherCAT and the TwinCAT System Manager offer
comprehensive diagnostic elements of this kind. Those diagnostic elements that are helpful to the controlling
task for diagnosis that is accurate for the current cycle when in operation (not during commissioning) are
discussed below.
EL922x
Fixed content: The content of this PDO is fixed and cannot be changed by the
System Manager.
Mandatory PDO. This PDO is mandatory and must therefore be assigned to a
Sync Manager! Consequently, this PDO cannot be deleted from the PDO
Assignment list
Version: 1.0
Commissioning
97