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IA261/262 WinCE User’s Manual CANopen Library

The CANopen specification defines several possible endpoints. The five endpoint objects listed

below are implemented in this protocol; others may be made available in the future.

• The Server SDO

• Four Static PDOs

• Synchronization Consumer

• Network Management Slave

• Node Guard or Heartbeat

SERVER SDO COMMUNICATION

The default server SDO (Service Data Object) is provided. The SDO communications path is

directly linked to the object dictionary; SDO messages contain information that relates the SDO to

a particular object. Data in every message is decoded, validated, and (if valid) eventually executed.

There are essentially two basic operations: read and write. Thus each complete SDO transfer

(which may be multiple messages) will either read or write a single object referenced in the

dictionary.

PDO COMMUNICATION

The PDO (Process Data Object) communications path is linked directly to the applicable

application object or objects. Thus the path is assumed by the device and no path information is

contained within the communication. Essentially the data is mapped internally to one or more

objects. Data is either statically mapped (compiled) or dynamically mapped (set at runtime). One

message can contain data from more than one object.

The protocol provided with this application note supports the four PDOs.

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