I'm about to set up a 1-wire network using 18x DS18B20 for ground temperature monitoring.
There will be 6 points of measure at about 50 meters from the arduino and about 50m between each point (an "almost perfect" star configuration with 6 branches)
I've read the GUIDELINES FOR RELIABLE LONG LINE 1-WIRE NETWORKS.
I will use CAT5E cable and each points of measure will use 3 DS18B20 at the same place for accuracy/reliability due to the fact that these points of measure will not be accessible later (underground). Low cost of these DS18B20 isn't an issue...
I'd like to know what is the best cabling solution for theses DS18B20 and if there is a better way to do it.
Here is 2 schematic with 2 differents options.
The first seems to be more common, the 3 DS18B20 are in parallel at the end of the cable.
The second is similar but the VDD and GND are splitted for each DS18B20 in case of defective device.
Is one of there 2 schematics better than the other and is there a better option?
Don't forget the CAT5E cable will be about 50m and there will be 6 in star configuration.
Reliability is the main factor...