Re: [Owfs-developers] How to Use Simultaneous

[Jan K. <jj...@gm...>]

Am 13.03.20 um 15:12 schrieb hwissing:
> Hello,
>
> I think one issue from the primary question is not answered..
>
> /" If I read from '/temperature' then I get them read in much faster
> *but I don't get a fresh conversion each time."*/
>
This is a very old question, and the mechanism has changed a bit since 2008.



>
> I have the same issue. First conversion with 8 DS18B20 sensors takes
> about 1 sec, immediately following requests take about 40 ms, but
> values are not updated. It takes a while till  updated values are
> acquired, then conversion takes longer.
>
That is because you read /<ID>/temperature instead of
/uncached/<ID>/temperature

But don't do this either. If you want simultaneos conversions, do instead

$ owwrite /simultaneous/temperature 1
$ sleep 1s
$ owread /uncached/<sensor0id>/latesttemp
$ owread /uncached/<sensor1id>/latesttemp
$ owread /uncached/<sensor2id>/latesttemp
$ owread /uncached/<sensor3id>/latesttemp
$ owread /uncached/<sensor4id>/latesttemp
$ owread /uncached/<sensor5id>/latesttemp
$ owread /uncached/<sensor6id>/latesttemp
$ owread /uncached/<sensor7id>/latesttemp

Latesttemp has the resolution of the previous non-simultaneous
conversion, or, after power-up of the sensor, the resolution set in the
sensor's EEPROM. You can adjust the through /<ID>/tempres.

See the manpage: https://github.com/owfs/owfs-doc/wiki/DS18B20

Kind regards

	Jan