Thanks for all the replies.
*Suggestion :*
*IF *reading == 85 *then *ignore reading
I will now implement something like this for each reading of the OWFS
server.
Most probably I will add the following else branch :
*else *reading = last_reading
Even if there is a valid 85 degree measurement, I don't expect this reading
do repeat that often. I expect something like 84,9x and 85,xx readings
nearby, as typically temperature readings change,
Eventually I will log, how often I see 85 degree readings on the sensors to
have an idea, how stable the 1-wire installation is. I did that, before I
used OWFS.
If this is never implemented in OWFS : I do it in my code. I never see 85
degrees again in my algorithm.
If the feature *85_ignore* is implemented in OWFS : no problem. Better
filter the problem twice than never.
This will make me happier, regardless whether the 85 degree readings are
because of :
- timing error of the OWFS code
- 4,7 k instead of 1.5 k
- power-on reset routine
- instable power supply
- 85°C readout is a feature rather than a bug
- Period.
- incorrect settings of simultaneous/temperature bit
- unfortunate instellar constellation
Maybe, but only maybe, I will investigate deeper, why I see what I reported
in my original post.
Happy programming
Ekkehard
2017-01-09 0:46 GMT+01:00 Mick Sulley <m...@sulley.info>:
> I don't know if this will help to explain the operation, but my code runs
> in a continuous loop -
>
> - Read all temperatures
> - Set the simultaneous/temperature bit
> - Perform logic operations, setting outputs to devices based upon
> temperatures read, etc
> - Log values to database
> - repeat.....
>
> OK ignore the first loop. The logic and logging takes more than 1 second,
> so when I read the temperatures they are all converted because it was
> initiated at step 2 on previous loop, no wait time and no 85 degree
> readings.
>
> I agree that there is a design fault with the DS1820, but it is nothing we
> can fix here, and Dallas are not going to do anything about it now.
> Hope that helps a bit
> Mick
>
>
>
> On 08/01/17 22:30, Jan Kandziora wrote:
>
> Am 08.01.2017 um 19:39 schrieb Roland Franke:
>
> It's still in there, as Stefano found the real bug causing problems with
> .../latesttemp.
>
> But this has also an problem (For me). I will read over OWLIB from the
> OWSERVER values out (Let me say the program collectd will read it with
> the onewire plugin). I have also not all my sensors (Type 28 = DS18B20)
> external powered, so the simultanues read of values will not work.
> On this way the value of latesttemp will be only updated, when the sensor
> is read on an second way. Only latesttemp will hold his value without any
> changes.
> So it is not (For me) complete right working as i was suggesting, that the
> update of that value will be also made. But this will be never be done.
>
>
> I'm sorry, I do not understand from the above what your problem is.
>
> Kind regards
>
> Jan
>
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