-

Defining the PDO Mapping

General information on Process Data Objects (PDO)

Click here to obtain basic information on PDOs

Working with PDOs in PLCnext Engineer

In PLCnext Engineer, the PDO mapping of a slave is implemented in the 'PDO Data' editor. By default, the editor lists the PDOs specified in the ESI file. A detailed editor description can be found in the topic "'PDO Data' Editor (EtherCAT Slave Device)".

To open this editor, double-click the slave to be configured in the PLANT. Then click 'PDO Data' in the editor area on the right.

In the 'PDO Data' editor you can perform the following operations:

Integrating a PDO into EtherCAT data frame and Data List

  By marking the checkbox in the 'Active' column 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 variable to be further processed in the application.
  By deselecting the checkbox in the 'Active' column of a PDO, it is not used in the EtherCAT data frame and hidden in the Data List.

Some basic and required PDOs may be activated by default and cannot be deactivated.

Modifying existing PDOs

Note
Note that the following operation is only possible if it is allowed by the slave.

  1. Open the PDO to be edited in the list. For that purpose left-click into the respective table row header ('Inputs' or 'Outputs' table) and click the icon on the editor toolbar.

    The 'Edit PDO Data' dialog box appears. The 'Entries' list in the lower half of the dialog box shows the objects which are currently members of the PDO.

  2. Deleting an object from the PDO:

    1. Select the object to be removed in the 'Entries' list and click the icon on the editor toolbar.
    2. Click the 'Apply' button.
    3. Repeat the steps a. and b. for each object to be deleted.
    4. Proceed with step 3. to add other objects to the PDO.
      To complete the editing and close the dialog box, click 'OK'.
  3. Adding an object to the PDO:

    Open the tab 'PDO Entry' of the 'Edit PDO Data' dialog box.

    In the section 'CoE object dictionary' (in the lower half of the editor), the available objects of the slave are listed.

    1. Select the object to be added.
    2. Click the 'Apply' button.
    3. Add further objects by repeating steps a and b.

    Alternatively you can specify the object to be added by filling in the fields in the sections 'General' and 'Settings'.

    Click here to display a description of the fields

  4. Open the 'General' tab again.

    In the grid under 'Entries', the previously selected objects are listed.

    Click 'Ok' to close the 'Edit PDO Data' dialog box.

Adding user-defined PDOs

Note
  • Note that the following operation is only possible if it is allowed by the slave.
  • Depending on the slave type, it may be necessary to delete a predefined PDO from the list before inserting a user-defined PDO (because the slave cannot manage more than the existing PDOs, for example). Information on this can be found in the technical manual of the slave device.

  1. Delete an existing PDO from the list if this is required by the current slave. For that purpose left-click into the respective table row header and click the icon on the editor toolbar.
  2. Click the icon on the editor toolbar to open the 'Add PDO Data' dialog box.
  3. In the dialog box, fill in or select the field entries on the 'General' tab:

    SectionElementDescription
    GeneralNameUser-defined name of the PDO.
    IndexUnique index of the PDO in the CoE Object Dictionary.

    Note
    Make sure that the index you are defining is available and free in the Object Dictionary of the slave.

    After selecting the 'Direction' of the new PDO (see next row), the system automatically proposes the first free index.
    DirectionDefines the data transfer direction of the PDO:
    • RxPDO: Write data to slave
    • TxPDO: Read data from slave
    FlagsMandatoryIf set, the PDO is marked as mandatory in the ESI file.

    This flag is read-only and cannot be changed for new PDOs. Instead, it is configured in the ESI file.
    Fixed ContextIf set, no additional entries can be added to the PDO.

    This flag is read-only and cannot be changed for existing or new PDOs. Instead, it is configured in the ESI file.
    Virtual PDOPDO's which do not have entries are marked as virtual.
    Entries In this tabular view, the already added objects are listed with their 'Name', 'Index', BitLength' and a user-defined comment (if available).

  4. Open the tab 'PDO Entry' of the 'Add PDO Data' dialog box.

    In the section 'CoE object dictionary' (in the lower half of the editor), the available objects of the slave are listed.

    1. Select the object to be added.
    2. Click the 'Apply' button
    3. Add further objects by repeating steps a and b.

    Alternatively you can specify the object to be added by filling in the fields in the sections 'General' and 'Settings'.

    Click here to display a description of the fields

  5. Open the 'General' tab again.

    In the grid under 'Entries', the previously selected objects are listed.

    Click 'Apply' to confirm the object population of the PDO.
    Then click 'Ok' to close the 'Add PDO Data' dialog box.

The new PDO is now listed in one of the tables 'Inputs' or 'Outputs' (depending on the 'Direction' you have selected in the 'Add PDO Data' dialog).