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EtherCAT Specification – Part 4
Data Link Layer protocols specification
Document: ETG.1000.4 S (R) V1.0.2
Nomenclature:
ETG-Number ETG.1000.4
Type S (Standard)
State D (Draft)
Version V1.0.2
Created by:
ETG
Contact:
info@ethercat.org
Filename
ET
G1000_4_S_R_V1i0i2_EcatDLLProtocols.doc
Date
07.01.2010
For ETG internal use only!
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EtherCAT Specification - Part 4 1
Trademarks and Patents
EtherCAT
®
is a registered trademark and patented technology, licensed by Beckhoff Automation
GmbH, Germany. Other designations used in this publication may be trademarks whose use by third
parties for their own purposes could violate the rights of the owners.
Disclaimer
The documentation has been prepared with care. The technology described is, however, constantly
under development. For that reason the documentation is not in every case checked for consistency
with performance data, standards or other characteristics. In the event that it contains technical or
editorial errors, we retain the right to make alterations at any time and without warning. No claims for
the modification of products that have already been supplied may be made on the basis of the data,
diagrams and descriptions in this documentation.
Copyright
© EtherCAT Technology Group 12/2009.
The reproduction, distribution and utilization of this document as well as the communication of its
contents to others without express authorization is prohibited. Offenders will be held liable for the
payment of damages. All rights reserved in the event of the grant of a patent, utility model or design.
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2 EtherCAT Specification - Part 4
DOCUMENT HISTORY
Version Comment
1.0 Adopted from IEC-Standard 61158-4 Type 12 for ETG use only!
1.0.1 BugFixes and clarifications according to
ETG1000_ES_D_V0i6_EcatSpecErrata.doc
1.0.2 BugFixes and clarifications according to
ETG1000_V1i0i2_ES_R_V0i7_EcatSpecErrata.doc
and IEC SC65C MT 9 editorial comments
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EtherCAT Specification - Part 4 3
CONTENTS
1 Scope ............................................................................................................................9
1.1 Scope of this standard and accordance to IEC Standards.......................................9
1.2 General .................................................................................................................9
1.3 Specifications ........................................................................................................9
1.4 Procedures............................................................................................................9
1.5 Applicability...........................................................................................................9
1.6 Conformance.......................................................................................................10
2 Normative references ...................................................................................................10
3 Terms, definitions, symbols and abbreviations...............................................................11
3.1 Reference model terms and definitions.................................................................11
3.2 Service convention terms and definitions..............................................................12
3.3 Common terms and definitions .............................................................................12
3.4 Additional EtherCAT definitions............................................................................13
3.5 Common symbols and abbreviations ....................................................................16
3.6 Additional EtherCAT symbols and abbreviations...................................................16
3.7 Conventions ........................................................................................................17
4 Overview of the DL-protocol..........................................................................................23
4.1 Operating principle ..............................................................................................23
4.2 Topology .............................................................................................................23
4.3 Frame processing principles ................................................................................23
4.4 Data-link layer overview.......................................................................................24
4.5 Error detection overview ......................................................................................25
4.6 Node reference model .........................................................................................25
4.7 Operation overview..............................................................................................26
5 Frame structure ............................................................................................................27
5.1 Frame coding principles.......................................................................................27
5.2 Data types and encoding rules .............................................................................27
5.3 DLPDU structure .................................................................................................30
5.4 EtherCAT DLPDU structure..................................................................................32
5.5 Network variable structure ...................................................................................49
5.6 EtherCAT mailbox structure .................................................................................49
6 Attributes .....................................................................................................................50
6.1 Management .......................................................................................................50
6.2 Statistics .............................................................................................................68
6.3 Watchdogs ..........................................................................................................71
6.4 Slave information interface ..................................................................................74
6.5 Media independent interface (MII) ........................................................................79
6.6 Fieldbus memory management unit (FMMU).........................................................82
6.7 Sync manager .....................................................................................................85
6.8 Distributed clock..................................................................................................92
7 DL-user memory...........................................................................................................95
7.1 Overview .............................................................................................................95
7.2 Mailbox access type ............................................................................................96
7.3 Buffered access type ...........................................................................................99
8 EtherCAT: FDL protocol state machines.....................................................................101
