Hello,
I am using OWFS since more than two years in different versions on a Raspi
2. This alone shows, that I think it is a very good program.
>From time to time there is the "85 degree" discussion. It is a clear design
flaw of the DS 18xxx chips to sent out a valid temperature reading, when an
error code should be sent out.
Everybody should be aware of the 85 degree flaw and mask it out,
Previously I thought, 85 degree is only happening, if the power supply is
insufficient, or shortly after power-on.
BUT it seems, that within OWFS there are other ways to read 85 degrees.
E.g. reading temperature value to quick after conversion command. This has
been reported on also Arduino 1-wire software. Or something else ?
I see the issue with OWFS Version 3.1p1 and 3.1p5. I did not check for
other versions or parasite powered DS chips.
Observation : the error code "85 Grad" is transmitted frequently with the
DS18B20. Only two participants on the bus, stable power supply, no
parasite power.
Open OWFS issues :
1) make sure wrong timing is not provoking 85 degree readings on the OWFS
server
2) filter out 85 degree "somewhere" in OWFS. Otherwise every user of the
OWFS server needs to do that filtering.
3) do statistics on 85 degree reading
pi@hsx03:~ $ date
Thu 5 Jan 17:20:33 CET 2017
pi@hsx03:~ $ sudo /opt/owfs/bin/owfs --version
/opt/owfs/bin/owfs version:
3.1p5
libow version:
3.1p5
owhttpd readings :
*top* <http://hsx03:2121/> highest level directory
*28.28DBA7010000* <http://hsx03:2121/28.28DBA7010000> 28.28DBA7010000
directory
*26.9D46F5000000* <http://hsx03:2121/26.9D46F5000000> 26.9D46F5000000
directory
*bus.0* <http://hsx03:2121/bus.0> bus.0 directory
uncached version <http://hsx03:2121/uncached/28.28DBA7010000>
*up* <http://hsx03:2121/> directory
*address* 2828DBA7010000A3
*alias*
*crc8* A3
*errata* errata <http://hsx03:2121/28.28DBA7010000/errata>
*family* 28
*fasttemp* 85
*id* 28DBA7010000
*latesttemp* 85
*locator* FFFFFFFFFFFFFFFF
*power* YES (1)
*r_address* A3000001A7DB2828
*r_id* 000001A7DB28
*r_locator* FFFFFFFFFFFFFFFF
*scratchpad*
50054B467FFF0C101C
*temperature* 21.6875
*temperature10* 85
*temperature11* 21.75
*temperature12* 21.6875
*temperature9* 85
*temphigh*
*templow*
*tempres*
*type* DS18B20
*temperature* 23.0625
*temperature10* 85
*temperature11* 23.125
*temperature12* 23.0625
*temperature9* 85
*temphigh*
*templow*
*type* DS18B20
*temperature* 23.1875
*temperature10* 85
*temperature11* 23.1875
*temperature12* 23.1875
*temperature9* 85
*temphigh*
*templow*
*tempres*
*type* DS18B20
Sometimes everything is o.k. :
*scratchpad*
72014B467FFF0E1057
*temperature* 23.125
*temperature10* 23.25
*temperature11* 23.25
*temperature12* 23.125
*temperature9* 23.5
I don't observe this on a DS18S20 :
*scratchpad*
2E004B46FFFF0D10C4
*temperature* 22.9375
*temphigh*
*templow*
*type* DS18S20
Best regards
Ekkehard
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
_______________________________________________
Owfs-developers mailing list
Owfs-developers@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/owfs-developers
