Hello, when I use 2 channels (ch0 and ch2), values on the both channels - 0x.f...ff. , herewith REF1 is not connected with external source. If I connect REF1+ with external power and REF1- with ground, borh channels takes normal value. If I use one channel (ch2), value from temparature sensor is normal, is REF1 connect with external source independent. Why is this happening?