Vanishing 1-wire sensors



  • Re: loosing 1-wire DS18B20 sensors during opreation in node-red

    Hello!

    I am runninh into troubles with my one wire setup as well, using cat5 ftp in bus topology. The sensors disappear every number of days. There are other users reporting this problem, but not so many. Has there been any progress on a solution? It lools like a hardreset of the 1-wire bus does not solve the problem. I have to powercycle the whole system in order to get it back online.

    Any ideas?

    Regards,

    Jasper Jackson


  • administrators

    @jasperjackson How many sensors do you have in the bus? Are you running it on Neuron/Axon or Unipi1?



  • Hi!

    I Have 8 Sensors on a Unipi 1.1 with a 2.5A Switched mode powersupply.

    I think i found something yesterday.
    When executing dmesg when the error occurs the kernel shows an almost infinite list of (..) SET TIME!

    That pointed me in the direction of the RTC spamming the Kernel somehow.

    I Disabled the RTC by remarking the following line in /boot/config.txt:

    dtoverlay=i2c-rtc,mcp7941x
    

    Things have been running for 24Hrs now without problems.
    I don't have the RTC battery mounted as i am using NTP.

    Regards,

    Jasper Jackson



  • @tomas_hora looks like disabeling the rtc kernel module fixed the problem. Things are still running perfectly :)



  • @jasperjackson said in Vanishing 1-wire sensors:

    @tomas_hora looks like disabeling the rtc kernel module fixed the problem. Things are still running perfectly :)

    Too early....

    unfortunatly i got another problem now after 3 days of operation. The problem is not the one wire sensors. I resetted the 1-Wirebus by disconnecting all the sensors. I then did a softreset of the raspberry/unipi, no sensors where found. It turns out there is a problem with the DS2482.

    
    [  273.108220] Driver for 1-wire Dallas network protocol.
    [  279.979503] ds2482 1-0018: DS2482 reset status 0x00 - not a DS2482
    
    

    Only a hardreset of the unipi resolves the problem. I'm running out of options here.. any help would be appreciated. I'll mount the rtc battery for now and see if the problems will go away. The main problem is that the unipi is controlling my heating in Austria and I live in holland. I'll probably need a second unipi to reset the main one :(.

    Regards,

    Jasper


  • administrators

    @jasperjackson If you have a free relay, you can try to wire the Data and 5V (or only GND) through a relay, and when it the sensors vanishes, restart the whole bus by the relay



  • @tomas_hora

    Hi Thomas!
    Thanks for your reply!

    When i disconnect the 1-Wire bus and reconnect it, (even when i give the unipi a softreset with no sensors connected before reconnecting the sensors again), the problem will not go away.

    It seems different than the problems other users reported. In their cases a hard reset of only the 1-Wire bus solves the problem, thus, putting it on a Relay makes it possible to remotely reset.
    In this case a hardreset of the 1-Wire bus does not resolve the problem.
    Could it be a problem with the I2C? The kernel driver reports that the DS2482 is not a DS2482. So it seems to me that the problem is I2C related, or the DS2484 hangs for some reason.
    Can I Analyse this somehow? I don't understand the i2cdetect command very well, maybe you can point me in the right direction here.

    I Have 2 Unipies by the way, one with shitty unshielded telephone cables through my whole house for the 1-Wire (Works flawlessly) and the one with CAT-5 FTP, (causing troubles).

    The Unipi is remotely accessible through SSH, so i can try almost everything remotely.

    Regards,

    Jasper Jackson



  • @jasperjackson said in Vanishing 1-wire sensors:

    @tomas_hora

    Hi Thomas!
    Thanks for your reply!

    When i disconnect the 1-Wire bus and reconnect it, (even when i give the unipi a softreset with no sensors connected before reconnecting the sensors again), the problem will not go away.

    It seems different than the problems other users reported. In their cases a hard reset of only the 1-Wire bus solves the problem, thus, putting it on a Relay makes it possible to remotely reset.
    In this case a hardreset of the 1-Wire bus does not resolve the problem.
    Could it be a problem with the I2C? The kernel driver reports that the DS2482 is not a DS2482. So it seems to me that the problem is I2C related, or the DS2484 hangs for some reason.
    Can I Analyse this somehow? I don't understand the i2cdetect command very well, maybe you can point me in the right direction here.

    I Have 2 Unipies by the way, one with shitty unshielded telephone cables through my whole house for the 1-Wire (Works flawlessly) and the one with CAT-5 FTP, (causing troubles).

    The Unipi is remotely accessible through SSH, so i can try almost everything remotely.

    Regards,

    Jasper Jackson

    Did some more research, this is the output of the failing unipi

    root@unipi:~# i2cdetect -y 1
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00:          03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
    10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
    20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
    30: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
    40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
    50: UU 51 52 53 54 55 56 UU 58 59 5a 5b 5c 5d 5e 5f
    60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
    70: 70 71 72 73 74 75 76 77
    

    And this is the output of my functioning unipi

    
    root@unipi:~# i2cdetect -y 1
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00:          -- -- -- -- -- -- -- -- -- -- -- -- --
    10: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
    20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    50: UU -- -- -- -- -- -- UU -- -- -- -- -- -- -- --
    60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- UU
    70: -- -- -- -- -- -- -- --
    
    

    I have a hard time imagining that this has something to do with my 1-Wire setup.


  • administrators

    @jasperjackson Nice catch. Anyway, I am afraid we cannot help you much. It is probably caused by some EMC on the 1W or I2C. You can try to reset reload the I2C driver if it helps:

    sudo rmmod i2c_dev
    sudo rmmod i2c_bcm2708

    sudo modprobe i2c_bcm2708
    sudo modprobe i2c_dev



  • @tomas_hora
    Ok! Thanks for the reply!, i'll look for emc sources, and i'll change the unipi and the raspberry with my other one to rule out hardware failure.
    I'll keep you posted if i find anything.

    Resetting the driver didn't work.
    I read in some other forum that i2cdetect returning all addresses usually means that the SDA of the I2C is bound to ground somehow.
    Maybe there lays a problem.

    Regards,

    Jasper Jackson



  • @jasperjackson said in Vanishing 1-wire sensors:

    @tomas_hora

    Hi Thomas!

    I didn't find anything yet...
    Looking at the cabeling again...

    What surprises me by the way is that you sell 1-wire sensors with 10 meters of unshielded cable??

    https://www.unipi.technology/1-wire-temperature-sensor-p63

    How can that be right?