[Rock-dev] Periodic task mandatory for needs_reliable_connection?

[Christian Rauch]

I indeed did not changed the task to be periodic, but defined for the 
device:

{{{
device(Dev::Sensors::CameraIDS, :as => 'camera1').
     [...]
     period(0.05).
     [...]
}}}

I guess this is the "minimum period" you have described? And this is 
just the hint for syskit and does not influence the call of the 
updateHook in any way?


Am 16.04.2014 14:43, schrieb Sylvain Joyeux:
> I don't really understand the question, sorry ...
>
> needs_reliable_connection is currently only a hint used by syskit (nothing
> else uses it). Syskit does *not* require the driver's task to be periodic,
> but it *does* require you to specify the "minimum period" (i.e. the minimum
> time between two consecutive samples) as produced by the device. Even if
> the task is non-periodic, the device usually is. The hokuyo driver, for
> instance, is not periodic (it processes data as it comes), and one simply
> declares the *device* period in syskit.
>
>
> On Tue, Apr 15, 2014 at 11:59 AM, Christian Rauch
> <Christian.Rauch at dfki.de>wrote:
>
>> Hi,
>>
>> is there another way to guarantee a reliable connection without periodic
>> samples (e.g. indexed samples)?
>>
>> Our camera (IDS) provides frames as they become available which are then
>> processed by the object detection component on a
>> 'needs_reliable_connection' port. The only workaround I see so far is to
>> call the camera task periodically which results in unneeded calls of the
>> updateHook.
>>
>> What is the common practice on this? Should sensors deliver data
>> periodically even if there is no new data or should processing components
>> not rely on every single data sample package but only on the last one? Even
>> if the task is periodic, a sample might be lost.
>>
>> Regards,
>> Christian
>>
>>
>> --
>>   Christian Rauch
>>   Space Robotics
>>
>>   Universität Bremen
>>   FB 3 - Mathematik und Informatik
>>   AG Robotik
>>   Robert-Hooke-Straße 1
>>   28359 Bremen, Germany
>>
>>   Zentrale: +49 421 178 45-6611
>>
>>   Besuchsadresse der Nebengeschäftstelle:
>>   Robert-Hooke-Straße 5
>>   28359 Bremen, Germany
>>
>>   Tel:     +49 421 178 45-6619
>>   Empfang: +49 421 178 45-6600
>>   Fax:     +49 421 178 45-4150
>>   E-Mail:  Christian.Rauch at dfki.de
>>
>>   Weitere Informationen: http://www.informatik.uni-bremen.de/robotik
>>
>>
>>
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>>
>>
>
>
>
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-- 
  Christian Rauch
  Space Robotics

  Universität Bremen
  FB 3 - Mathematik und Informatik
  AG Robotik
  Robert-Hooke-Straße 1
  28359 Bremen, Germany

  Zentrale: +49 421 178 45-6611

  Besuchsadresse der Nebengeschäftstelle:
  Robert-Hooke-Straße 5
  28359 Bremen, Germany

  Tel:     +49 421 178 45-6619
  Empfang: +49 421 178 45-6600
  Fax:     +49 421 178 45-4150
  E-Mail:  Christian.Rauch at dfki.de

  Weitere Informationen: http://www.informatik.uni-bremen.de/robotik


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