AKD EtherCAT | 4 EtherCAT Profile
4.6 Flexible PDO Mappings
In addition to the fixed PDO mapping the so-called flexible mapping of real-time objects is
possible.
Available objects for PDO mapping are listed in the object dictionaries ("Appendix" (
59)). All objects with the entry "yes" in column "PDO map." can be used.
Restrictions of flexible mapping:
l
An odd length PDO is not allowed.
o
In the Rx(=set-point)-direction the dummy-object 0x0002 sub 0 with a length of 8 bits
can be used to make the PDO-length even.
o
In the Tx(=actual value)-direction one sub-index of the manufacturer status object
0x2002 sub 1..4 can be used to guarantee the even length of the Tx-PDO.
o
These special mappings may be used if the objects 0x6060 and 0x6061 have to be
used in the mapping.
l
The allowed PDOs have up to 32 bytes (Tx) or 20 bytes (Rx). They are built from smaller
PDO modules with a maximum length of 8 bytes. These are built by using the mapping
objects 0x1600 to 0x1603 and 0x1a00 to 0x1a03.
The configuration is similar to the described sequence for the fixed mappings:
1. The mapping selection is cleared (write 0 to object 0x1C12 sub 0 and 1C13 sub 0)
2. As the AKD - implementation is based on CANopen the real-time data are build from up to
4 PDOs with 8 bytes in both directions. These PDOs are built in the same way as in a
CAN-drive with the objects 0x1600 - 0x1603 and 0x1A00 - 0x1A03. Unused PDOs must
be cleared with writing 0 to the subindex 0.
3. SDO write access to object 0x1C12 sub 1 .. 4 with the PDOs (0x1600 .. 0x1603), that
should be used in receive direction of the AKD (set point values).
4. SDO write access to object 0x1C13 sub 1 .. 4 with the PDOs (0x1A00 .. 0x1A03), that
should be used in transmit direction of the AKD (actual values).
5. SDO write access to the objects 0x1C12 sub 0 and 0x1C13 sub 0 with the number of
mapped PDOs in this direction.
See an example in chapter "Flexible PDO Mappings" (
p. 44) .
The cyclically used data are visible in the PDO-assignment window for the Inputs and Out-
puts of the Sync Managers. Default setting are the fixed PDOs 0x1701 and 0x1B01 (visible
contents when selected in the PDO list).
44
Kollmorgen | kdn.kollmorgen.com | October 2017
