Check about crc errors and short circuit
85degrre is the 'default' memoru value
Em quinta-feira, 12 de junho de 2014, Loren Amelang <lo...@pacific.net>
escreveu:
> I have owfs and owserver running on a BBB under Ubuntu 12.04. It seems to
> be working, most of the time...
>
> One of the DS18B20 sensors is linked via Node-RED to store a new
> temperature reading to the emoncms site at five minute intervals. Sometimes
> it draws nice smooth 12-bit resolution graphs for days. But occasionally
> the temperature will get stuck for up to an hour, and then make a step
> change.
>
> I'm pretty well convinced that emoncms is storing what they are sent, and
> Node-RED is sending what it reads from the
> /sys/devices/w1_bus_master1/28-000000884d88/w1_slave file.
>
> --> I'm not sure how to tell if the file is being updated. The date/time
> metadata does not change when readings change. Is there some way to verify
> that a fresh reading has been written? Maybe the file is intentionally only
> written if the value changes?
>
> Apparently each of the readings is done separately?
> temperature 24.6875
> temperature10 85 <--
> temperature11 24.75
> temperature12 24.6875
> temperature9 24.5
>
>
> Watching the owserver page, I sometimes see readings that don't exactly
> make sense. This sequence was captured by manually copying and pasting and
> then refreshing the web page, so 15 seconds or more between groups:
> ---
> temperature 30.8125
> temperature10 30.75
> temperature11 30.875
> temperature12 30.8125
> temperature9 30.5
>
> temperature 30.8125
> temperature10 30.75
> temperature11 30.75
> temperature12 30.8125
> temperature9 30.5
>
> temperature 30.8125 <-- looks like this is separate from temp12?
> temperature10 30.75
> temperature11 30.875
> temperature12 30.875
> temperature9 30.5
>
> temperature 30.8125
> temperature10 30.75
> temperature11 30.875
> temperature12 30.8125
> temperature9 30.5
>
> temperature 30.8125
> temperature10 30.75
> temperature11 30.875
> temperature12 30.875
> temperature9 30.5
>
> ubuntu@ubuntu-armhf:~$ cat
> /sys/devices/w1_bus_master1/28-000000884d88/w1_slave
> e8 01 4b 46 1f ff 08 10 07 : crc=07 YES
> e8 01 4b 46 1f ff 08 10 07 t=30500
>
> ubuntu@ubuntu-armhf:~$ cat
> /sys/devices/w1_bus_master1/28-000000884d88/w1_slave
> ed 01 4b 46 7f ff 03 10 e2 : crc=e2 YES
> ed 01 4b 46 7f ff 03 10 e2 t=30812
>
> ubuntu@ubuntu-armhf:~$ cat
> /sys/devices/w1_bus_master1/28-000000884d88/w1_slave
> e8 01 4b 46 1f ff 08 10 07 : crc=07 YES
> e8 01 4b 46 1f ff 08 10 07 t=30500
> ubuntu@ubuntu-armhf:~$
>
> temperature 30.8125
> temperature10 30.75
> temperature11 30.875
> temperature12 30.8125
> temperature9 30.5
> ---
>
> --> I know the value in the w1_slave file is usually the 12-bit value, but
> could it sometimes be one of the lower precision values?
>
> --> Sometimes it seems like having the owserver web page open makes it
> much more likely that occasional low-precision values will appear in the
> file - is that possible?
>
>
> Here is a sequence from today, when the temperature should have been
> slowly but evenly rising:
> ---
> 11 Jun 2014 19:35:24.136[owfs payload]
> 25.375
> 11 Jun 2014 19:40:24.210[owfs payload]
> 25.500
> 11 Jun 2014 19:45:24.383[owfs payload]
> 25.500
> 11 Jun 2014 19:50:24.371[owfs payload]
> 25.500
> 11 Jun 2014 19:55:24.413[owfs payload]
> 26.000
> 11 Jun 2014 20:00:24.502[owfs payload]
> 26.062
> 11 Jun 2014 20:05:26.447[owfs payload]
> 26.187
> 11 Jun 2014 20:10:26.461[owfs payload]
> 26.187
> 11 Jun 2014 20:15:26.496[owfs payload]
> 26.187
> 11 Jun 2014 20:20:26.531[owfs payload]
> 26.687
> 11 Jun 2014 20:25:26.554[owfs payload]
> 26.500
> 11 Jun 2014 20:30:26.946[owfs payload]
> 26.500
> 11 Jun 2014 20:35:26.615[owfs payload]
> 26.500
> 11 Jun 2014 20:40:26.648[owfs payload]
> 27.125
> 11 Jun 2014 20:45:26.673[owfs payload]
> 27.125
>
> temperature 27.3125
> temperature10 27.25
> temperature11 27.375
> temperature12 27.3125
> temperature9 27
>
> 11 Jun 2014 20:50:26.696[owfs payload]
> 27.000
>
> cat /sys/devices/w1_bus_master1/28-000000884d88/w1_slave
> b6 01 4b 46 7f ff 0a 10 a2 : crc=a2 YES
> b6 01 4b 46 7f ff 0a 10 a2 t=27375
> ubuntu@ubuntu-armhf:~$
>
> temperature 27.4375
> temperature10 27.5
> temperature11 27.375
> temperature12 27.4375
> temperature9 27.5
>
> temperature 27.4375
> temperature10 27.5
> temperature11 27.5
> temperature12 27.5
> temperature9 27.5
> ---
>
> --> I realize that kind of cut and paste logging is hopelessly imprecise
> when the owfs values are apparently being updated every 15 seconds. Is
> there some better way to see what is going on?
>
>
> I don't need 15 seconds, the file only gets read once per five minutes.
> I've tried changing timeouts in the owserver interface and in the
> /etc/owfs.conf file. The values from the conf file show in the web page,
> and if I change them there they revert immediately, but they don't affect
> the actual operation. The hardware seems stuck at 15 seconds.
>
> --> Any clues what I might be missing to change the w1 update timing?
>
> --> I'm seeing the "15 seconds" with a scope on the hardware bus. Does the
> timeout value set the time between each individual reading, or the time to
> update the full sequence of 9/10/11/12/temp or whatever else is being
> separately read?
>
> --> Maybe when you use the w1 interface, the "w1" timeout overrides
> "volatile"? But that is set to 30 and I still get 15...
>
>
> --> If you think this is just "noise" on the readings, is there some place
> in the owfs system where I could insert some severe digital filtering? It
> seems kind of tacky to keep querying your output and filtering that for my
> purposes.
>
>
> --> While I'm asking questions, does anyone know if trying to read DS18B20
> devices with 3.3V hardware causes them to read high? Sensors that match my
> thermocouple thermometer exactly when read in a 5V system read 2 to 6
> degrees C higher on the 3.3V BBB. I've verified the logged temperature
> matches the reported 1-Wire bits. The readings are stable and (except for
> the occasional periods of low resolution noted above) change smoothly. I
> have not gone to the effort of trying to determine if this is a fixed
> offset or a ratiometric error...
>
> For my production system with a dozen sensors along 100+ feet of cable,
> I'm sure a proper 5V interface with active pullup/downs will be required.
> But I'm surprised I'm getting offsets when testing with local devices!
>
>
> Thanks for any clues,
>
> Loren
>
> | Loren Amelang | lo...@pacific.net <javascript:;> |
>
>
>
>
>
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--
Roberto Spadim
SPAEmpresarial
Eng. Automação e Controle
------------------------------------------------------------------------------
HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions
Find What Matters Most in Your Big Data with HPCC Systems
Open Source. Fast. Scalable. Simple. Ideal for Dirty Data.
Leverages Graph Analysis for Fast Processing & Easy Data Exploration
http://p.sf.net/sfu/hpccsystems
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