Process Data is exchanged cyclically with the EtherCAT Master. Process Data Objects (PDO) are objects from the object dictionary mapped as process data. Therefore, the object dictionary must be configured before configuring the process data objects.

PDO configuration example

A PDO is an object filled with PDO entries. These entries are objects from the object dictionary which can be mapped as PDO. Therefore, there are few things to consider.

Index 0x1600 to 0x17FF are reserved for RxPDOs.
Index 0x1A00 to 0x1BFF are reserved for TxPDOs.
Object entries must have OBJACCESS_RXPDOMAPPING or OBJACCESS_TXPDOMAPPING flags.

Therefore, it's not possible to map an object only with OBJACCESS_RXPDOMAPPING flag in a PDO with Index 0x1A00 to 0x1BFF and vice versa.

Examples

Create a RxPDO and map an entry from array object entry from CoE Examples to the PDO.

EC_API_SLV_SHandle_t*       ptSlave     = pApplicationInstance_p->ptEcSlvApi;
EC_API_SLV_SCoE_ObjEntry_t* ptObjEntry  = NULL;
EC_API_SLV_SPdo_t*          ptRxPdo1600 = NULL;
EC_API_EError_t             error       = EC_API_eERR_INVALID;
 
error = (EC_API_EError_t)EC_API_SLV_PDO_create(ptSlave, "RxPDO", 0x1600, &ptRxPdo1600);
 
error = (EC_API_EError_t)EC_API_SLV_CoE_getObjectEntry(ptSlave, 0x2100, 1, &ptObjEntry);
 
error = (EC_API_EError_t)EC_API_SLV_PDO_createEntry(ptSlave, ptRxPdo1600, "SubIndex 001", ptObjEntry);

Help functions

The EtherCAT SDK provides with a set of functions to access the process data. These help functions are available with the PDO suffix. For further information please refer to the documentation.

Function	Description
EC_API_SLV_PDO_get	Get object from PDO list
EC_API_SLV_PDO_getOffset	Get PDO offset in process data
EC_API_SLV_PDO_getLength	Get PDO length
EC_API_SLV_getInputProcDataLength	Get input process data length
EC_API_SLV_getOutputProcDataLength	Get output process data length
EC_API_SLV_PDO_getEntryCount	Get PDO entry count
EC_API_SLV_PDO_getEntryDataLength	Get entry data length
EC_API_SLV_setInputData	Write input process data
EC_API_SLV_getOutputData	Read output process data
EC_API_SLV_PDO_setData	Set PDO data
EC_API_SLV_PDO_getData	Get PDO data
EC_API_SLV_PDO_setEntryData	Set PDO entry data
EC_API_SLV_PDO_getEntryData	Get PDO entry data
EC_API_SLV_PDO_setFixedMapping	Define if PDO entries adjustable or not
EC_API_SLV_PDO_enable	Enable PDO from process data mapping
EC_API_SLV_PDO_disable	Disable PDO from process data mapping
EC_API_SLV_PDO_enabled	Check PDO status
EC_API_SLV_PDO_setAssignment	Define if SyncManager content is adjustable or not
EC_API_SLV_PDO_addPadding	Add padding to process data to avoid alignment issues