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8 EtherCAT Communications
8 - 2
NX-series EtherCAT Coupler Unit User’s Manual (W519)
8-1
Structure of CAN Application Proto-
col over EtherCAT (CoE)
EtherCAT allows the use of multiple protocols for communications. However, the EtherCAT Slave Ter-
minal uses the CAN application protocol over EtherCAT (CoE) as the device profile for the CAN appli-
cation protocol. The CoE is a communications interface that is designed to provide compatibility with
EtherCAT devices. The CAN application protocol is an open network standard.
The following figure shows how the CoE is structured for an EtherCAT Coupler Unit.
The object dictionary for the CAN application protocol is broadly divided into PDOs (process data
objects) and SDOs (service data objects).
PDOs are contained in the object dictionary. The PDOs can be mapped in the object dictionary. The
process data is defined by the PDO mappings. PDOs are used in PDO communications for periodic
exchange of process data.
SDOs are the objects that can be read and written. SDOs are used in non-periodic SDO communica-
tions (event-driven message communications).
If you use the CoE interface to set the object dictionary for PDOs and SDOs, you can provide EtherCAT
devices with the same device profiles as the CAN application protocol.
EtherCAT Coupler Unit
EtherCAT physical layer
SDO (mailbox)
NX Unit application
Object dictionary
PDO mappings
PDO communications (cyclic)
EtherCAT data link layer
Registers
Mailbox
Process data
FMMU
SyncManager
Application layer
Transitions of
communications
states
Summary of Contents for NX-ECC201
Page 38: ...Sections in this Manual 36 NX series EtherCAT Coupler Unit User s Manual W519...
Page 46: ...1 EtherCAT Networks 1 8 NX series EtherCAT Coupler Unit User s Manual W519...
Page 56: ...2 Features and System Configuration 2 10 NX series EtherCAT Coupler Unit User s Manual W519...
Page 82: ...4 Part Names and Functions 4 14 NX series EtherCAT Coupler Unit User s Manual W519...
Page 100: ...5 Designing the Power Supply System 5 18 NX series EtherCAT Coupler Unit User s Manual W519...
Page 214: ...9 Setting Up Slave Terminals 9 44 NX series EtherCAT Coupler Unit User s Manual W519...
Page 254: ...11 EtherCAT Coupler Unit Functions 11 30 NX series EtherCAT Coupler Unit User s Manual W519...
Page 278: ...12 Communications Performance 12 24 NX series EtherCAT Coupler Unit User s Manual W519...
Page 340: ...14 Maintenance and Inspection 14 8 NX series EtherCAT Coupler Unit User s Manual W519...
Page 400: ...Appendices A 60 NX series EtherCAT Coupler Unit User s Manual W519...
Page 401: ...Index 1 NX series EtherCAT Coupler Unit User s Manual W519 I Index...
Page 405: ......