IL•1F CANopen DS301

3 Basics

3.2Communication profile

CANopen manages communication between the network devices with object dictionaries and objects. A network device can use process data objects (PDO) and service data objects (SDO) to request the object data from the object dictionary of another device and, if permissible, write back modified values.

The following can be done by accessing the objects of the network de- vices

Exchange parameter values

Start motion functions of individual CAN bus devices

Request status information

3.2.1Object dictionary

Each CANopen device manages an object dictionary which contains all objects for communication.

Index, subindex The objects are addressed in the object dictionary via a 16 bit index. One or more 8 bit subindex entries for each object specify individual data fields in the object. Index and subindex are shown in hexadecimal nota- tion with a subscript "h".

The following example shows the index entries and subindex entries for the object receive PDO4 mapping, 1603h for mapping in R_PDO4.

Index

Subindex

Object

Meaning

1603h

00h

Number of elements

Number of subindexes

1603h

01h

1st mapped object

First object for mapping in

 

 

R_PDO4

R_PDO4

1603h

02h

2nd mapped object

Second object for mapping

 

 

R_PDO4

in R_PDO4

1603h

03h

3rd mapped object

Third object for mapping in

 

 

R_PDO4

R_PDO4

Table 3.2 Examples of index and subindex entries

0198441113586, V2.01, 11.2008

Fieldbus interface

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Schneider Electric DS301 manual Communication profile, Object dictionary, Index Subindex Object Meaning