by itself, owfs does not actively poll the slaves. it only access the bus to
get the informations queried by the client application (ls, owread, ...)
1-wire is a slow bus on which many sensors (slave) may be attached.
Discovering every slaves connected and reading theirs state is a relatively
long process that consume time and bandwidth. This may become an issue when
client(s) keep querying owfs for sensor data at too short intervals.
To overcome this, owfs maintain in an internal cache the informations
delivered to the client(s).
Some informations are known to be static because they don't change by itself
(address, type, templow, ...) and other are flagged volatile (temperature,
sensed, count, ...) .
Cache lifetime depends on this volatility. (by default, volatile values are
marked expired 15 seconds after they where collected) That means that owfs
will access the bus to obtain updated values if the cached data is expired,
but this occurs ONLY when a client ask for this data.
as most of information is static,
2011/3/22 Roberto Spadim <robe...@spadim.com.br>
> you should read the directory, or cat the value if using owfs (filesystem)
> to 'poll' the ow network
>
> 2011/3/22 nick <n...@kiwi-hacker.net>:
> >>> My current setup checks outdoor and greenhouse temp to determine
> >>> whether to turn on a 240VAC power switch to heat up (or cool down)
> >>> the greenhouse. owfs polls every 15 seconds?
> >
> >> owfs never poll on itself !
> >
> > If owfs never polls itself, how does the cached directory structure get
> > updated? Maybe i am misunderstanding something here...?
> >
> > Cheers.
> >
> >
> >
> >
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>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
>
> ------------------------------------------------------------------------------
> Enable your software for Intel(R) Active Management Technology to meet the
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--
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be a part of the solution? Download the Intel(R) Manageability Checker
today! http://p.sf.net/sfu/intel-dev2devmar
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