General CANopen definitions  Issue 01/05 
  CANopen Option Module    Operating Instructions 
14  6SE6400-5BC00-0BP0 
A maximum of 8 bytes of data can be transferred in a PDO. In conjunction with a 
synchronization message, sending as well as accepting PDOs can be 
synchronized throughout the network, ("synchronous PDOs"). The assignment of 
application objects to a particular PDO (transfer object) can be set using a structure 
description ("PDO-Mapping") saved in the OD. This means it can be adapted to the 
particular application requirements of a specific device. 
SDOs are transferred as acknowledged data transfer between two CAN objects in 
the form of a peer-to-peer coupling between two network nodes. The object 
directory entry is addressed by specifying the index and subindex of the OD entry. 
When SDO messages are transferred, this involves an additional overhead. 
Standardized, event-orientated alarm messages ("Emergency_Messages") with a 
high priority are provided for messages associated with device faults/errors. 
The functionality required to prepare and to start a distributed automation system in 
a coordinated fashion corresponds to the mechanisms defined under CAL network 
management (NMT) as well as the "Node-Guarding" principles or heartbeat which 
are used as basis for cyclic node monitoring.  
CAN message identifiers can be allocated to PDOs and SDOs by directly entering 
identifiers in the data structures of the object directory or, for simple system 
structures, by using pre-defined identifiers. 
General information 
MICROMASTER, in conjunction with the CANopen option module, also provides, 
for the various MICROMASTER types, different CANopen modes from the DSP 
402 profile (Drives and Motion Control). 
For MICROMASTER 420/430), only the Velocity Mode is available. The 
MICROMASTER 440 supports the Velocity Mode and Profile Torque Mode modes.  
When transferring net data via CANopen, a differentiation is made between 
process data (PDO) and parameter data (SDO). 
In order to transfer process data, CAN telegrams can be set using so-called PDO 
mapping. After being powered-up, MICROMASTER has the following default 
settings: 
•  Receive PDO1  6040H control_word 
•  Receive PDO5  not mapped 
•  Receive PDO6  not mapped  
•  Send PDO1  6041H status_word 
•  Send PDO5  not mapped 
•  Send PDO6  not mapped 
The mapping for PDO1 is fixed. Free PDO mapping in compliance with CANopen 
is not possible using MICROMASTER for this PDO.  
The mapping for PDO5 and PDO6 can be modified using CANopen. 
The mapping is subject to several restrictions that are described in more detail in 
Section 5.4.