[etherlab-users] R: SDO stress

Thomas Bitsky, Jr. tbj at automateddesign.com
Thu May 23 16:19:31 CEST 2013


This is probably a useless aside, but what servo drive are you using? I
have nothing but problems with SDO reads and writes on the Kollmorgen AKD
drive, regardless of the EtherCAT master used. If I don't space them out by
100ms or so, the drive gives inconsistent responses. I've spent a year
trying to improve the situation, but to no avail. My plan is to use the
EtherCAT master as the controller so I can avoid SDO usage with the drive.

Thomas C. Bitsky Jr. | Lead Developer
ADC | automateddesign.com
P: 630-783-1150 F: 630-783-1159 M: 630-632-6679


On Thu, May 23, 2013 at 5:10 AM, paluan.luca at tiscali.it <
paluan.luca at tiscali.it> wrote:

>
>
> Hello,
> I've been struggling with Sdo write since 3 mounths without a
> solution up to now.
> I wrote a stress test which writes and reads what
> written on three Sdo for three Servos in a preemptive real time loop:
>
> after some hours of work the application hangs and the ethercat master
> shows a download/upload Sdo Timeout error problem.
> I've checked that
> only one read or one write takes place at a time, for example:
> start
> write SDO1 for first servo
> end write SDO1 for first servo
> start read
> SDO1 for first servo
> end read SDO1 for first servo
> start write SDO2 for
> first servo
> end write SDO2 for first servo
> start read SDO2 for first
> servo
> end read SDO2 for first servo
> ...
> start write SDO1 for second
> servo
> end write SDO1 for second servo
> start read SDO1 for second servo
>
> end read SDO1 for second servo
> start write SDO2 for second servo
> end
> write SDO2 for second servo
> start read SDO2 for second servo
> end read
> SDO2 for second servo
> ....
> So each write doesn't overlap each read for
> each servo.
> As far as I know managing Sdo inside real time loop is not
> reliable: I mean it usually works, but for a software which manages
> Servos is not enough.
> If someone has advices or suggestions is welcome.
>
> Best Regards, Luca Paluan
>
> ----Messaggio originale----
> Da:
> RBenYehuda at manz.com
> Data: 22/05/2013 13.36
> A: "etherlab-users at etherlab.
> org"<etherlab-users at etherlab.org>
> Ogg: [etherlab-users] SDO stress
>
> Hey
>
>
> I have been tracking the following problem:
> I generate bulk of sdo
> reads and sdo writes ( upload / downloads).  after some time the sdo
> read
> hangs.  I made a capture with tcpdump and noticed that the
> failure lies in etherlab. it appears that
> after some time etherlab
> does not try to send a mail box response read from the mailbox, even
> though
> the slave "said" he has the data available ( by replying to read
> request).
> Why this bug fixed ?
>
> thank you
> raz
>
>
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>
>
>
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