PDO
This tab appears if you click on a process data object (PDO) in the tree view.
Process Data Objects (PDOs) are CAN telegrams which transport process data without a protocol overhead.
- RxPDOs are received by the device.
- TxPDOs are sent by the device.
A device sends its input data with TxPDOs and receives the output data in the RxPDOs. This designation is retained in TwinCAT.
No. | Description |
|---|---|
1 | CAN identifier of the PDO. For two send and receive PDOs per node, CANopen provides Default Identifiers. These can then be changed. |
2 | The Transmission Type determines the send behavior of the PDO. 255 corresponds to the event-driven sending (see: Setting the transmission type). |
3 | The length of the PDO depends on the created variables and can therefore not be edited here. |
4 | Enter the value for the Event Timer in ms. For send PDOs (RxPDOs), PDOs are sent again after a timer has elapsed. For receive PDOs (TxPDOs), the arrived PDOs are monitored, and the box state of the node may be modified. TwinCAT creates corresponding inputs in the node object directory on the basis of the parameters entered here. These are transferred via SDO at the system start. The entries can be viewed in the SDO tab (see: SDOs). This function can be deactivated via the checkbox Automatic PDO Parameter Download on the CAN node tab (see: CAN node). |
5 | The PDO length check can be disabled here. |