loosing 1-wire DS18B20 sensors during opreation in node-red



  • I'm having trouble with EVOK, when I read 1-wire (DS18D20) sensors in node-red flow, after some time sensors are lost (if I look at uni.pi.ip/rest/all, for sensor ID I get "lost": true). If I restart EVOK service, no 1-wire sensors are shown.

    Is there any known solution for this?

    BR Luka

    PS. I am running Rasbian on RPI3.



  • Update: as mentioned only software reboot is not enough, I have to unplug and plug UNI.pi board to electricity to have 1-wire sensors reading again.

    Could it be, that this is hardware problem (for connection I use standard UTP patch cable)?


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  • tnx for quick reply - will try to ground FTP cables and will report back.



  • I did as sugested I grounded cables for 1wire network connection. But it doesnt solve the issue.

    I guess it has to be power issue - I have 1x Unipi, 1x Rasperry Pi 3 and 1x EMO-8R module in addition 14x 1wire DS1820 temperature sensors.

    I am trying to figure out maximal power needed and so far I come with:
    1.5mA/1wire DS18b20
    1.5A/Unipi+RPi - 2.5A - RPi 3 model B (but only 1.1A is provided through Uni.pi) in opreational mode 250-500mA, that leaves around 1A for UniPi board and another 750mA for EMO-R8.

    Bottom line 2.4A should be enough for uni.pi main board, but not necesaray for extension module - could this cause 1wire lost problems?