I made temperatur monitoring system on Netduino plus 2 with DS18B20. In my installation I connect only one DS18B20 to one Digital I/O port. Some of my DS18B20 are on long cable - more than 100m. I cannot read them. On shorter cable (20-50m) everything works ok. Of course I use resistors but on cable longer than 100m it doesn't work. Does anyone know how to read DS18B20 on cables longer than 100m?