Shelly Plus 1 + Addon + n.3 DS18B20,
connected with 10m (32 ft) extension cable (10 m for each sensor). The type of cable is described in the two attached images: 2xtwisted pairs 22AWG (0.32mmq) individually shielded. One conductor of each of the two twisted pairs plus the shield, are all connected to the negative, at both ends.
Connecting the three temp probes without extension I read the three temperature values correctly, but adding the three cable extensions it no longer works.
I checked the insulation of the conductors with the continuity tester without detecting anomaly.
Maybe the shield has to be connected to the negative pin only on the Addon side to avoid the capacitive effect?
Does anyone have any suggestions as to the possible cause of the problem?
Many Thanks
Extension cable DS18B20 temp sensor.jpg87123 XL cable signal-audio_2 pairs shielded.png