3 Common Slave Specifications
3 - 4 EtherCAT Communication Unit USER’S MANUAL (I574-E1)
3-3 Process Data Objects (PDO)
The process data objects (PDOs) are used to transfer data during cyclic communications in realtime.
There are two types of PDOs: reception PDOs (RxPDOs) which receive data from the controller, and
transmission PDOs (TxPDOs) which send statuses from the inverter to the Host Controller.
The EtherCAT application layer can hold multiple objects to enable the transferring of inverter process
data. The contents of the process data are described in the PDO mapping object and the Sync Man-
ager PDO assignment object.
The PDO mapping indicates the mapping for application objects (realtime process data) between the
object dictionary and PDO.
The number of mapped objects is described in sub-index 00 hex of the mapping table. In this mapping
table, 1600 to 17FF hex are for RxPDOs and 1A00 to 1BFF hex are for TxPDOs.
The following table is an example of PDO mapping.
3-3-2 PDO Mapping Settings
Operation status, present value, etc
Operation command, target value, etc
6UUU hex UU hex
6TTT hex TT hex
YYYY hex YY hex
Object A Object B
PDO length: 32 bits