I did as sugested I grounded cables for 1wire network connection. But it doesnt solve the issue.
I guess it has to be power issue - I have 1x Unipi, 1x Rasperry Pi 3 and 1x EMO-8R module in addition 14x 1wire DS1820 temperature sensors.
I am trying to figure out maximal power needed and so far I come with:
1.5mA/1wire DS18b20
1.5A/Unipi+RPi - 2.5A - RPi 3 model B (but only 1.1A is provided through Uni.pi) in opreational mode 250-500mA, that leaves around 1A for UniPi board and another 750mA for EMO-R8.
Bottom line 2.4A should be enough for uni.pi main board, but not necesaray for extension module - could this cause 1wire lost problems?