'PDO Data' Editor (EtherCAT Slave Device)

The following information refers to a specific, typical device type. Your screen may differ.

This help topic describes the 'PDO Data' editor of an EtherCAT slave device in the PLANT. EtherCAT slave devices are child elements of the 'EtherCAT' node (which represents the EtherCAT Master).

This topic contains the following sections:

General information on Process Data Objects (PDO)

Click here to obtain basic information on PDOs

PDO implementation in PLCnext Engineer

In PLCnext Engineer, the PDO mapping is implemented in the 'PDO Data' editor. This editor is available for each EtherCAT slave device in your PLANT and provides access to the PDOs which are defined for the particular slave (according to the CAN-over-EtherCAT protocol).

The 'PDO Data' editor provides the process data objects specified in the EtherCAT slave information (ESI) file. If the slave device is an EtherCAT bus coupler, its PDO list contains the process data of the connected I/O modules.

You can select/deselect the 'Active' checkbox of particular items. (Some basic and required PDOs, however, are activated by default and cannot be deactivated.) The checkbox is described in detail in the table below.

If allowed by the slave, PDOs can be modified (i.e., objects can be added or removed in existing PDOs) and/or user-defined PDOs can be defined.

Columns in the PDO list tables

The editor tab provides two tables:

'Inputs' contains the (Transmit, Tx) PDOs which are read by the Master from the slave (data direction slave > Master, i.e., input process data from the perspective of the EtherCAT Master).
'Outputs' contains the (Rx)PDOs which are written by the Master to the slave (data direction Master > slave, i.e., output process data from the perspective of the EtherCAT Master).

Both tables have the same columns:

Column Description

Active If you expand the column by clicking the icon in the column header, the objects contained in this PDO become visible.
By marking the 'Active' checkbox of a PDO, it is embedded into the EtherCAT data frame and is available in the Data List of the slave. There, each process data item can be assigned to a global IEC variable to be further processed in the application. An example is provided below this table.
By deselecting the 'Active' checkbox, the PDO is not used in the EtherCAT data frame and hidden in the Data List.

Index Each process data item contained in a PDO has another index value which corresponds to the index range of the CoE Object Dictionary.
Therefore, this column provides two different information:

On PDO level (also visible if the PDO row is collapsed), the index of the PDO is visible. This index uniquely identifies the PDO.

Inside the PDO (visible if the line is expanded), the index identifies the embedded object. In this case, the index corresponds to the object identifier in the Object Dictionary of the slave and consists of index and subindex, separated by a colon (MainIndex:SubIndex).

Name Name of the PDO or of the object inside a PDO.

Bit Length Length of the PDO or of the object inside a PDO.

Type Data type of the object. This column is only visible for objects inside a PDO (i.e., PDO is expanded).

Column	Description
Active	If you expand the column by clicking the icon in the column header, the objects contained in this PDO become visible. By marking the 'Active' checkbox of a PDO, it is embedded into the EtherCAT data frame and is available in the Data List of the slave. There, each process data item can be assigned to a global IEC variable to be further processed in the application. An example is provided below this table. By deselecting the 'Active' checkbox, the PDO is not used in the EtherCAT data frame and hidden in the Data List.
Index	Each process data item contained in a PDO has another index value which corresponds to the index range of the CoE Object Dictionary. Therefore, this column provides two different information: On PDO level (also visible if the PDO row is collapsed), the index of the PDO is visible. This index uniquely identifies the PDO. Inside the PDO (visible if the line is expanded), the index identifies the embedded object. In this case, the index corresponds to the object identifier in the Object Dictionary of the slave and consists of index and subindex, separated by a colon (MainIndex:SubIndex).
Name	Name of the PDO or of the object inside a PDO.
Bit Length	Length of the PDO or of the object inside a PDO.
Type	Data type of the object. This column is only visible for objects inside a PDO (i.e., PDO is expanded).

What do you want to do?

Note that the following operations are only possible if they are allowed by the slave.

Edit a PDO by adding or deleting contained objects

Add a new PDO