ElmoMC CANopen DS 301 Implementation Guide - Manual (Page 30)

Chapter 5: Process Data Objects (PDOs)
5.1 Receive PDOs
A Receive Process Data Objects (RPDO) is used to receive predefined and unconfirmed
messages. An RPDO is received through use of an event, which may be asynchronous
(such as “Message Received”) or synchronous with the reception of a SYNC. Four receive
PDOs are used with the Elmo drive. The following must be indicated:
ƒ
Objects that can be mapped and have write access can be mapped to each RPDO.
ƒ Execution of the mapped objects begins in the lower index of the relevant mapping
object (0x1600 - 0x1603).
ƒ High-priority objects, used for high-speed motion modes, can be mapped to an RPDO
to avoid the overhead in using the standard interpreter. This mapping is dynamic,
according to the setting of the PDO mapping at index 0x1600 - 0x1603 by the
appropriate SDO. In a drive, only one fast reference object can be mapped to a single
RPDO. The fast reference objects that can be mapped to an RPDO are:
Index Meaning Access
2001h PVT motion command Write
2002h PT motion command Write
2003h Reserved
2004h ECAM entry Write
ƒ All type of objects can be mapped. Unsigned8, Signed8, Unsigned16, signed16,
Unsigned32, and SignedT32 can be mapped. Manufacture specific object such as
Binary interpreter and PVT\PT can also be mapped.
ƒ RPDO1-4 can be freely mapped. The only constraints are that only one of the 0x2001
– 0x2004 objects can be mapped to an RPDO at a time, and that none of these objects
can be mapped to more than one RPDO simultaneously.
ƒ Data of RPDOs mapped to objects 0x2001-0x2004 is processed immediately upon
reception.
ƒ Data of RPDOs is queued and it is passed for interpretation and execution at the
next available background loop (Idle Loop) and according to the transmission type.
ƒ The transmission type associated to the Rx mapping can be either synchronous
where the data of the RPDO is passed for executing after the occurrence of the
following SYNC (value =1), or asynchronous (value=255 or 254) in which the data of
the RPDO is passed to the application immediately after reception and processed on
the next Idle loop.
ƒ At most one copy of each mapped RPDO can be stored for synchronous execution. If
same RPDO arrives before next SYNC, it overwrites the previous with no
notification.
CANopen DS 301 Implementation Guide Process Data Objects (PDOs)
MAN-CAN301IG (Ver. 2.1)
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