CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
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RTR-only synchronous
The RTR-only synchronous mode is activated when receiving a
remote-transmit-request message, i.e. SYNC objects. This transmission type
is only useful for TxPDO. In this situation, the CAN-8123/CAN-8223/CAN-8423
will update the DI/AI value when receiving any SYNC object. And, if the RTR
object is received, the CAN-8123/CAN-8223/CAN-8423 will respond to the
TxPDO object. The following figure shows the mechanism of this transmission
type.