Parameterization and commissioning
EL6751
130
Version: 3.5
Fig. 130: Flow chart for CAN cycle (Sync Multiplier > 1)
Synchronization with SM2 (SM3) event
Whereas in operating mode Sync Multiplier = 1 the synchronous RxPDOs must be sent completely before
the EtherCAT input data is updated, this can extend over n EtherCAT cycles in operation with Sync Multiplier
= n. The beginning of the CAN cycle is still the same as in operation with Sync Multiplier = 1. After the
TxPDO delay has expired (on the flow chart it is assumed that the TxPDO delay is smaller than the input
shift time), transmission of the synchronous RxPDOs begins. If the input shift time expires during that time,
the EtherCAT input data containing the most recent data from all TxPDOs received up to this time is
updated. After that, the next event is waited for each time until the last EtherCAT cycle within the CAN cycle
is reached. In the middle EtherCAT cycles, the data of the asynchronous RxPDOs to be sent always receive
the latest value, whereas the data of the synchronous RxPDOs are only updated in the first EtherCAT cycle.
