Hi guys, hi zeronix
You need more components (resistors) because you need a lower resistance (value) than 4.7K on this bus with 7 probes, for a good operation of your star bus with more than one probe.
4.7K is a frequently given average value for the OneWire bus, which fits all processors pins and their output current (which differ from one processor to another). For the Uno, I go down to 560 ohms, because the output current of the Uno processor allows it. With 3 times 4.7K, it's as if you had only one 1.6K resistor (you could also put 5 resistors of 4.7K, for a result of 1K).