5x18BS20 and time of response

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galexis
2016-10-26
2016-10-29

  • galexis - 2016-10-26

    I have connect 5 DS18B20 on my Rpi3. The time to ask value of 5 sensor is more than 4 seconds !
    I see in documentation of DS18B20 the time for resolution 12bits is 750 ms. In 10bits resolution time is only 187ms.
    How can I change resolution of my sensors ? It's not in the library in codesys, I think it's in raspbian.
    Could you help me ?
    Bests regards.

     

  • eschwellinger

    eschwellinger - 2016-10-26

    Hi,

    better to ask this in the RaspberryPi.org User Forum.

    BR
    Edwin

     

  • galexis - 2016-10-29

    I have find solution to change resolution on internet:
    You have to use an other gpio than gpio4, like gpio25 in pin22 and only 1 ds18b20 plug in to do change:

    sudo git clone https://github.com/danjperron/BitBangingDS18B20
    cd BitBangingDS18B20
    sudo gcc -lrt -o configDS18B20 configDS18B20.c

    sudo ./configDS18B20 25

    I have change resolution of 5 ds18b20 to 10 bits. Time now must be 187.5ms x 5= 938ms. But, the cycle time is still 4 seconds !
    Is it CODESYS ? Raspbian ? I don't understand ....
    Help ...

     

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