Chapter 4. Data Communication Protocol of the CANopen
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Data is transmitted through a variety of COBs (Communication
Object) in the CANopen data Frame.
Process Data Object (PDO) is used to transmit the data requiring real
time transmission (Real time data), while Service Data Object (SDO)
is used to transmit the data not requiring real time transmission.
4.1.2 SDO communication
SDO communication is used for Peer to Peer communication of the
data not requiring real time transmission between two CANopen
Devices (e.g. setting the parameter value).
It is possible to read/write all the Objects in the Object Directory using
SDO communication. It specifies the Object by the combination of
Object Index and Sub-Index.
4.1.3 PDO communication
PDO communication is used to send and receive the data requiring
real time transmission (Real Time data). It is transmitted without
overhead or confirmation of the Protocol (Index, Sub-index, Data), i.e.
used for IO communication.
PDO is divided into two types depending on the transmission
direction; RPDO (Receive PDO) where data is transmitted from
communication master, and TPDO (Transmit PDO) where data is
transmitted to communication Master.
Sinus H CANopen is embodied for PDO for Frequency converter use
out of CiA 402 Drive and Motion Control, which provides PDO1 and
PDO3 only.
Using PDO1 is not possible with PDO3 at the same time.
