West Control Solutions KS 800 CANopen Interface Manual - Manual (Page 14)

KS 800 CAN-Interface
3.3.4 Synchronous receive PDO
When receiving a synchronous PDO, the data remain in the Rx buffer at first (CAN-controller)
without being transmitted to the controller. For this, the received flag for the relevant channel is
set. This signals that new data for the controller are ready for receiving. The fReceived flag is
reset by the controller. The interaction of Sync message and synchronous PDOs is shown in the
following diagram.
Caution: When receiving another synchronous PDO before the next Sync message, the PDO
received last is transmitted to the controller. i.e. PDOs can be overwritten, earlier
information will be lost.
Explanation of the diagram:
At time S.n, the data of PDOs which were received between S.n-1 and S.n are passed on
to the controller. These are the data for channel 1, 4 and 6.
At time S.n+1, the data of PDOs which were received between S.n and S.n+1 are passed
on to the controller. These are the PDOs for channel 3, 6 and 8.
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