[etherlab-users] Multirate system - Simulink fundamental sample time / Ethercat bus frequency

Dr.-Ing. Wilhelm Hagemeister hm at igh-essen.com
Wed Jan 5 10:54:30 CET 2011


Hello Jasper,

if you change the sample time of the EtherLab blocks to a lower rate
than the rest of your model, it should be possible to run the IO slower
than the rest. Don't forget to set solver-tasking mode to multitasting
(I expect you did so). Anyway the sampling of all channels for data
transfer is done with the highest rate regardless in witch sample time
domain they exist (depending on decimation which can be adjusted).

To be exact, I have tried with models having different sample times (up
to 3) also with EtherCat-IO but I never had a model where the highest
sample rate has no IO but I would expect this should be no problem.

Please post a simple example...

regard Wilhelm.

Am 04.01.2011 16:25, schrieb Westpfahl Jasper:
> Hello Etherlab-Users,
> 
> I'm using a slave with a minimal sample time of 125e-6 s but due to numerical stability, I need to calculate some subsystems of the Simulink model more often (have a lower sample time). These subsystems do not contain Ethercat-component blocks. Has anybody experience with this?
> 
> It seems that the models fundamental sample time always determines the Ethercat bus cycle time. Is it possible to set the Ethercat cycle frequency to a lower value than the fundamental sample frequency?
> 
> Any idea or hint would be greatly appreciated.
> 
> thanks for reading and a happy new year!
> Jasper Westpfahl
> _______________________________________________
> etherlab-users mailing list
> etherlab-users at etherlab.org
> http://lists.etherlab.org/mailman/listinfo/etherlab-users




More information about the Etherlab-users mailing list