Communication
45
DS 301 and DS 402 specification
The application layer communication protocol in REPL-01 is
based on the CANopen DS 301 communication profile and
DS 402 device profile for drives and motion control. The protocol
specifies the Object Dictionary in the module, as well as
communication objects for exchanging process data and acyclic
messages.
REPL-01 implements the following message types:
• Process Data Object (PDO)
•The PDO object is used for cyclic I/O communication, i.e.
process data.
• Service Data Object (SDO)
•The SDO object is used for acyclic data transmission.
• NMT response services
•Used for identity and status signaling both during the start-up
and in runtime.
The object dictionary is described in chapter
CANopen object
dictionary
on page
51
.
Process Data Objects (PDO)
Process Data Objects (PDOs) are used for exchanging time-
critical process data between the master and the slave. Tx PDOs
are used to transfer data from the slave to the master and Rx
PDOs to transfer data from the master to the slave.
PDO mapping defines which application objects are transmitted
inside a PDO. These typically include the Control and Status
Words, References and Actual Values, but most dictionary objects
and drive parameters can be mapped for cyclical communication.
The REPL-01 has one receive PDO (Rx PDO) and one transmit
PDO (Tx PDO). In each PDO, 0…16 application objects can be
mapped. PDOs are mapped to objects during configuration (the
NMT_CS_PRE-OPERATIONAL_1 and NMT_CS_PRE-
OPERATIONAL_2 states).
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