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erratics readings with 1wire Pi

116 Views - Created 04/05/2019

04/05/2019

Posted by:
anthropo

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Hello,

I have an 1wire Pi (2014 version) and recently i have changed my PI model B to Pi model B+ with 1Gb.
I don't know if there is a relation, but after rebuilding all the domoticz server, with owfs installed with apt on raspbian,(/usr/lib/owfs/owfs version:  3.1p5, libow version:  3.1p5)

i have erratics readings : sometimes 12 family components are read, sometimes not (DS2406 dual addressable switch).

More, 28 family (DS18B20 temperature sensor ) are nearly always presents.

ll /mnt/1wire/
total 0
drwxrwxrwx 1 root root 4096 mai    4 21:57 28.057F35050000
drwxrwxrwx 1 root root 4096 mai    4 21:57 28.330936050000
drwxrwxrwx 1 root root 4096 mai    4 21:57 28.BC9A35050000
drwxr-xr-x 1 root root 4096 mai    4 18:10 alarm
drwxr-xr-x 1 root root 4096 mai    4 18:10 bus.0
drwxr-xr-x 1 root root 4096 mai    4 18:10 settings
drwxrwxrwx 1 root root 4096 mai    4 21:57 simultaneous
drwxr-xr-x 1 root root 4096 mai    4 18:10 statistics
drwxr-xr-x 1 root root 4096 mai    4 18:10 structure
drwxr-xr-x 1 root root 4096 mai    4 18:10 system
drwxr-xr-x 1 root root 4096 mai    4 18:10 uncached
ll /mnt/1wire/
total 0
drwxrwxrwx 1 root root 4096 mai    4 21:59 12.12EDA0000000
drwxrwxrwx 1 root root 4096 mai    4 21:59 12.F20DB9000000
drwxrwxrwx 1 root root 4096 mai    4 21:59 12.F2B8B9000000
drwxrwxrwx 1 root root 4096 mai    4 21:59 28.057F35050000
drwxrwxrwx 1 root root 4096 mai    4 21:59 28.330936050000
drwxrwxrwx 1 root root 4096 mai    4 21:59 28.BC9A35050000
drwxr-xr-x 1 root root 4096 mai    4 18:10 alarm
drwxr-xr-x 1 root root 4096 mai    4 18:10 bus.0
drwxr-xr-x 1 root root 4096 mai    4 18:10 settings
drwxrwxrwx 1 root root 4096 mai    4 21:59 simultaneous
drwxr-xr-x 1 root root 4096 mai    4 18:10 statistics
drwxr-xr-x 1 root root 4096 mai    4 18:10 structure
drwxr-xr-x 1 root root 4096 mai    4 18:10 system
drwxr-xr-x 1 root root 4096 mai    4 18:10 uncached

and when it's party they are all here ( i can't show it, it's not party time):

12.F9B8B9000000:Porte_Entree
12.2EEBA0000000:Porte_Couloir
12.12EDA0000000:Porte_Bureau
12.53EBA0000000:Porte_Arriere
12.F20DB9000000:Porte_Cellier
12.F2B8B9000000:Porte_Garage
28.2BC435050000:Temp_Exterieure
28.330936050000:Temp_Piscine
28.BC9A35050000:Temp_Moteur
28.057F35050000:Temp_Grenier
29.97F10D000000:Tableau_Electrique

What can i do  ? if have checked everything  it seems to me. I also tried to add --ActivePullUp to my init script,

in my /boot/config.txt i have
 

dtparam=i2c=on
dtparam=i2c1=on
dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on
dtparam=i2c_baudrate=400000
core_freq=250

Can you help please ?

04/05/2019

Posted by:
andrew

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Location:
United Kingdom

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Hello

If the only change in your setup was changing from the model B to the B+ then the most probable cause is the power supply. 

The B+ uses about 30% more power than the model B so if the power supply is running near its limits it could cause the voltage to drop on the 5V rail or introduce additional noise which may cause erratic readings on the 1 Wire bus.

Try measuring the 5V pin on the 1 Wire Pi with a multimeter, or oscilloscope if you have one, and see if the voltage is 5V and if there is any change when you try to read from any of the devices on the 1 Wire bus.

AB Electronics UK Tech Support

05/05/2019

Posted by:
anthropo

Users Avatar

I'll measure but i have a 5v 6A power supply connected

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