Fast CAN Queue (unbuffered)

Received messages are no longer buffered on the EL6751. The RxQueue should therefore be large enough to hold all messages that could theoretically be received within a single EtherCAT cycle.

The received messages no longer have to be confirmed. The EL6751 increments the RxCounter when new messages are received.

In the transmission direction, only data dependent on the changed TxCounter and the NoOfTxMessages is copied, so that the number of parallel messages in the queue should no longer affect the runtime (only the NoOfTxMessages).

Since the EL6751 operates in 3-buffer mode (so that it always has a buffer in which to copy received CAN messages), the unused messages may contain incorrect or old data.

The object directory can be read on the CoE-Online tab.
If index 0x1C32:08 is set to 1, the EL6751 measures its internal processing time per cycle and stores the maximum value in index 0x1C32:05. Thus, you can see if the EL6751 will finish within the EtherCAT cycle.
Normally, that is, in CANopen mode, measurement starts automatically when the system transitions from PREOP to SAFEOP. In Fast CAN Queue mode, it does not start automatically. In this case, the measurement must be started by setting index 0x1C32:08 to 1. If 0 is written to 0x1C32:08, the measurement ends.

The Fast CAN Queue must not contain further CANopen or CAN Layer 2 nodes.