[etherlab-users] Ethercat hello world

Mladen Knezic mladen_knezic at etfbl.net
Thu Feb 24 12:28:57 CET 2011

Hello Thomas,

> Anyway it is interesting to know why my "etherlab cstruct" reports 
> 0x7000, 0x7010, etc ... (bitwise data) and in the example plays with 
> 0x3001 trought a bytewise access.
> Where is this documented ?

'etherlab cstruct' returns the ESI configuration from the slave E2PROM which 
is burned after the slave production by its vendor. The same information can 
be extracted from the slave's ESI file in XML (for Beckhoff products can be 
downloaded from the official site, or if you have TwinCAT software installed 
you can find it in the folder /path/to/twincat/Io/EtherCAT). You have to open 
the EL2xxx.xml with some software for XML files browsing (e.g. Microsoft XML 
Notepad is free tool), and you will find configuration and mappings for 
various devices. You will find the mapping for EL2008 is matching those found 
with 'etherlab cstruct'.

Example you are referring to works with the old configuration version of 
EL2004 device (you can find it in EL2xxx.xml under the Product Code 
0x07d43052 with Revision No. 0x00000000 and the new version is woth the same 
Product Code but with the Revision No. 0x00100000 which has mapping on 0x7000 
etc.). But I must note that both in EL2004 (both old and new configurations) 
and EL2008 the bitwise mapping is used (you have four entries-subindices, 
each for one bit of data) and not the bytewise mapping as you stated.


Mladen Knezic
Research and Teaching Assistant
Faculty of Electrical Engineering
Banja Luka, Bosnia and Herzegovina
Web: www.etfbl.net

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