Although if slaves actually have SDOs (ie. support CoE) then they’re required 
to provide an online CoE dictionary, which “ethercat sdos” will read and 
display even if the slave does not define any in its SII.  (Although not all 
vendors obey the rules.)

 

If the slave doesn’t support CoE then they’re not really SDOs, they’re just 
potential PDOs, and in that case you’re at the mercy of whether the SII EEPROM 
information is correct or not as mentioned below.

 

Slave vendors are required to provide correct information in the SII XML, which 
TwinCAT can read but Etherlab cannot.  But you can use TwinCAT to reprogram the 
SII EEPROM from the SII XML, which Etherlab can then read.  It’s usually not 
necessary to do this unless the vendor has left the EEPROM in a really bad 
state, as SDO information is usually only needed during interactive 
experimentation and commissioning, not normal operation, and you can usually 
get similar or better information from manuals.

 

You can use the “ethercat slaves -v -p <pos>” command to see information about 
a slave, including whether it supports CoE or not.

 

From: Erik Euving
Sent: Friday, 16 September 2016 01:05
To: Dr.-Ing. Wilhelm Hagemeister <[email protected]>
Cc: [email protected]
Subject: Re: [etherlab-users] Regarding SDOs

 

Dear Wilhelm,

Thanks for your answer! Makes sense!

Kind regards,

Erik




 

[email protected] <mailto:[email protected]>  | 
+31641615351

 

On 14 September 2016 at 16:53, Dr.-Ing. Wilhelm Hagemeister <[email protected] 
<mailto:[email protected]> > wrote:

Hallo Erik,

slaves have the "Slave Information Interface" (SII). This is more or less a 
EEROM which stores necessary information for the master to configure the slave.
See also: http://etherlab.org/en/ethercat/faq.php

Vendors can decide to store the SDO-Dictionary in the EEPROM or not. Because 
the EtherCat-Master only works with the information which can be fetched from 
the SII, it will present the SDOs if the dictionary is stored in the EEPROM 
otherwise not.

Regards Wilhelm.

Am 14.09.2016 um 10:19 schrieb Erik Euving:

Dear all,

I have a question regarding SDOs of a specific slave I use for my setup,
namely the D1-N-36-E0-2-1-00 drive by HIWIN. As you can see in the
attached screenshot, when I type the "~> ethercat -p 1 sdos" command, I
do not receive any feedback from the slave. When I type the same command
for my other slave (E-Box by Ketels) I get the full list.

My understanding about the inner workings of Ethercat and Etherlab is
very limited, but could someone explain why a slave would not give me
the list of available SDOs? I have a manual and I am able to access
individual SDOs (e.g. "~> ethercat upload -p 1 -t int8 0x6060 0" for
Mode of Operation) but requesting the full list is not possible.

Thanks!

Kind regards,
Erik


[email protected] <mailto:[email protected]>  
<mailto:[email protected] <mailto:[email protected]> > |
+31641615351 <tel:%2B31641615351> 

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