[etherlab-users] Working counter interpretation

Christoph Schröder christoph.schroeder at helmholtz-berlin.de
Thu Feb 23 10:52:53 CET 2017

Hi all,

I have a question regarding the WorkingCounter. The WC actually shows me
an error (incomplete) despite everything working fine. If I use one
slave I get the following message in the kernel log:
 > [Thu Feb 23 10:32:17 2017] EtherCAT 0: Domain 0: Working counter
changed to 2/3.
Why 2/3? I have only one slave and even if the master itself is counted
too, shouldn't it be 2/2?

If I add one more slave I get this message:
[Thu Feb 23 10:34:54 2017] EtherCAT 0: Domain 0: Working counter changed
to 4/6.
This adds 3 to the nominal value and 2 to the actual counter. This leads
to the questions:
1. Why is 3 the nominal counter value per slave? Shouldn't it be 1 count
per slave when a EtherCAT frame passes by?
2. If the 3 is correct, what am I missing? I didn't loose any frames and
communication works just fine (which is the reason why I never paid any
attention to this odd value but I would like to use it for error handling).

Thanks and best regards,


Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.

Aufsichtsrat: Vorsitzender Dr. Karl Eugen Huthmacher, stv. Vorsitzende Dr. Jutta Koch-Unterseher
Geschäftsführung: Prof. Dr. Anke Rita Kaysser-Pyzalla, Thomas Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

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D-14109 Berlin


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