ElmoMC CANopen DS 301 Implementation Guide - Manual (Page 31)

ƒ A change in RPDO mapping wipes any pending synchronous or asynchronous
queued RPDO s of that type. The user must be aware and responsible.
ƒ Change of transmission type from synchronous to asynchronous does not wipe
pending instances.
ƒ Changing transmission type to synchronous does not wipe any queued
asynchronous instances.
ƒ Objects can receive data from SDO and RPDO on the same time. User must be aware
that the result of such case cannot be predicted. The final value of the object maybe
either the SDO or the RPDO data.
ƒ RPDOs cannot be retrieved by a remote transmitting (RTR).
Error Cases
When an RPDO fails to interpret, an emergency message 0x6300 0x01 is transmitted.
There might be several objects mapped into the same RPDO. The EMCY message
identifies the objects that failed. A failure is consider when the received data could not be
interpreted or executed. Refer to the “RPDO error handling” section in this manual.
In some cases Elmo’s error code is produced. The emergency may contain this error code.
Example of RPDO mapping:
In order to set PDO1 to program PT-type motion commands (object 0x2002), set the object
at index 0x1600 (PDO mapping, type defined by object 0x21).
Sub-index 0 Unsigned8 1
Sub-index 1 Pt-type 0x20020040
The PDO mapping may be set using a single expedited SDO, which will be:
Byte Value Description
0 0x23 Initiate download, expedited, index valid, data valid.
1 0 Index (LO) to store at.
2 0x16 Index (HI) to store at.
3 1 Sub-index to store at.
4 0x40 Data length
5 0 Sub-index
6 0x02 High data
7 0x20 Low data
Table 5-1: Service Data Objects
CANopen DS 301 Implementation Guide Process Data Objects (PDOs)
MAN-CAN301IG (Ver. 2.1)
5-2