[etherlab-users] Questions about DC

[Andreas Stewering-Bone]

Hello,

please check a newer version of the stable branch.

Florian did some work on better syncing in DC mode.

Best regards

Andreas

Am 31.10.2011 16:10, schrieb Gianluca Medini:
> Good morning, I'm using the Igh ethercat master to play motor drives 
> with DC.
> What I see is a time to have a little difference in timing (registser 
> 0x92c) that is very long (the first time I start the master is about 
> 30 seconds, if I restart also much more).
> Inspecting the 0x92c seems we have oscilation that need   a long time 
> to end.
> I don't know if this is normal since I've no experience with other 
> masters.
> However I've seen an asimmetry in code for user and hard real time.
> 1) In user example
>         // write application time to master
>         clock_gettime(CLOCK_TO_USE, &time);
>         ecrt_master_application_time(master, TIMESPEC2NS(time));
>
> 2) In rtai example.
> ....
>      tv.tv_usec += 1000;
>         if (tv.tv_usec >= 1000000)  {
>             tv.tv_usec -= 1000000;
>             tv.tv_sec++;
>         }
>         ecrt_master_application_time(master, EC_TIMEVAL2NANO(tv));
>
>   In the RTai example the clock is taken a first time before the main 
> loop and after is calculated manually (incrementing 1000 mSec), in 
> these way (it seems to me) the time I give to master is always with 
> the (small enough) jitter of the RTai scheduler.
>
> I'm wrong ?
>
>
>
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>    


Mit freundlichem Gruß

Andreas Stewering-Bone

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