3-3
3 EtherCAT Communications
NJ/NX-series CPU Unit Built-in EtherCAT Port User’s Manual (W505)
3-1 EtherCAT Communications Types and Settings
3
3-1-1 CoE (CAN Application Protocol over EtherCAT)
Object Dictionary
The object dictionary is a data table within the device that interfaces the application and commu-
nications. It describes the information handled by the device. Each piece of information is called
an object. Each object is assigned a 4-digit hexadecimal index.
Each object is divided into a data type area, a CoE communications area, and a manufacturer-
specific area.
Process data communications is used to read and write the process data in the CoE communi-
cations area in these objects.
SDO communications is used to read and write the parameters within the manufacturer-specific
area in these objects.
PDO
SDO
1000 hex
1600 hex
3000 hex
EtherCAT
CANopen device
Communications
Object dictionary
Parameters
Process Data
Device Type
Object contentIndex
Application
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